Federal Motor Vehicle Safety Standards; Tire Pressure Monitoring Systems, 53079-53101 [05-17661]

Agencies

• National Highway Traffic Safety Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 70, Number 172 (Wednesday, September 7, 2005)]
[Rules and Regulations]
[Pages 53079-53101]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-17661]


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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Parts 571 and 585

[Docket No. NHTSA 2005-22251]
RIN 2127-AJ70


Federal Motor Vehicle Safety Standards; Tire Pressure Monitoring 
Systems

AGENCY: National Highway Traffic Safety Administration, DOT.

ACTION: Final rule; response to petitions for reconsideration.

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SUMMARY: This document responds to petitions for reconsideration 
requesting changes in our April 8, 2005 final rule establishing a new 
Federal motor vehicle safety standard (FMVSS) requiring installation in 
new light vehicles of a tire pressure monitoring system (TPMS) capable 
of detecting when one or more of a vehicle's tires is significantly 
under-inflated. The petitions for reconsideration are granted in part 
and denied in part, and through this document, we are amending the 
standard and related provisions accordingly.

DATES: Effective Date: The amendments made in this final rule are 
effective October 7, 2005. Voluntary compliance is permitted 
immediately.
    Petitions for Reconsideration: If you wish to submit a petition for 
reconsideration for this rule, your petition must be received by 
October 24, 2005.

ADDRESSES: Petitions for reconsideration should refer to the docket 
number above and be submitted to: Administrator, Room 5220, National 
Highway Traffic Safety Administration, 400 Seventh Street, SW., 
Washington, DC 20590.
    See the SUPPLEMENTARY INFORMATION portion of this document (Section 
VI; Rulemaking Analyses and Notices) for DOT's Privacy Act Statement 
regarding documents submitted to the agency's dockets.

FOR FURTHER INFORMATION CONTACT: For non-legal issues, you may call Mr. 
George Soodoo or Mr. Samuel Daniel, Office of Crash Avoidance Standards 
(Telephone: 202-366-2720) (Fax: 202-366-4329).
    For legal issues, you may call Mr. Eric Stas, Office of Chief 
Counsel (Telephone: 202-366-2992) (Fax: 202-366-3820).
    You may send mail to these officials at National Highway Traffic 
Safety Administration, 400 Seventh Street, SW., Washington, DC 20590.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Summary of Decision
II. Background
    A. The TREAD Act
    B. Rulemaking History Prior to the April 2005 Final Rule
    C. The April 8, 2005 Final Rule
III. Petitions for Reconsideration
IV. Discussion and Analysis
    A. Low Tire Pressure Warning Lamp Activation Requirements
    B. TPMS Malfunction Indicator Lamp (MIL) Activation Requirements
    1. What Constitutes a TPMS Malfunction?
    2. MIL Disablement
    C. Telltale Requirements
    D. Tire-Related Issues
    1. Spare Tires
    2. Tire Reserve Load
    3. Minimum Activation Pressure
    E. Owner's Manual Requirements
    1. Lead Time
    2. Content of Required Statement
    3. Other Owner's Manual Issues
    F. Test Procedures
    1. Test Conditions
    2. Vehicle Cool-Down Period
    3. 2-psi Adjustment (Temperature Correction)
    4. Calibration Time
    G. TPMS Reprogrammability
    H. Sharing of TPMS Servicing Information
    I. Phase-In Calculations
V. Benefits and Costs
VI. Rulemaking Analyses and Notices

I. Summary of Decision

    This document responds to 15 petitions for reconsideration related 
to our April 8, 2005 final rule \1\

[[Page 53080]]

establishing FMVSS No. 138, Tire Pressure Monitoring Systems. The 
petitioners raised a variety of issues, most of which involved requests 
for technical changes to the standard (see section IV of this document 
for a complete discussion of issues raised in the petitions and their 
resolution). We have decided to grant the petitions in part and to deny 
them in part.
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    \1\ 70 FR 18136 (April 8, 2005) (Docket No. NHTSA-2005-20586-1).
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    The following points highlight the amendments to Standard No. 138 
that we are adopting in response to the petitions for reconsideration 
of the April 8, 2005 final rule (excluding a few minor editorial 
changes).
     We have decided to postpone the compliance date for the 
standard's required TPMS-related owner's manual statement until 
September 1, 2006 (Model Year 2007), thereby granting petitions' 
request for additional lead time to incorporate the required language 
into the vehicle owner's manual. We do not believe that extending the 
compliance date in this manner (consistent with a recommendation in one 
of the petitions) would result in any safety consequences. Delay of the 
owner's manual requirements would not impact the functioning of the 
TPMS or the warnings that it provides, and we expect that even before 
that date, TPMS-equipped vehicles would have some owner's manual 
statement presenting relevant information to the consumer.
    We specifically note that delay in the compliance date for the 
standard's owner's manual requirements does not impact vehicle 
manufacturers' responsibility to provide TPMSs complying with FMVSS No. 
138 on a schedule consistent with the phase-in commencing on October 5, 
2005, as set forth in the April 8, 2005 final rule.
     The agency has decided to retain the final rule's 
requirement for the TPMS malfunction indicator lamp (MIL) to illuminate 
whenever there is a malfunction that affects the generation of 
transmission of control or response signals in the vehicle's tire 
pressure monitoring system. However, in response to petitions, we have 
decided to amend the standard's test procedures for malfunction 
detection to clarify that telltale lamps will not be disconnected 
because such malfunctions will be indicated during the bulb check(s) 
required under the standard. Specifically, we are amending S6(k) by 
adding the following statement: ``When simulating a TPMS malfunction, 
the electrical connections for the telltale lamps shall not be 
disconnected.''
     The lack of synchronization between the timing of 
compliance for compliance under FMVSS No. 138 and the TPMS telltale 
requirements of FMVSS No. 101, Controls and Displays, have been 
remedied through an earlier amendment to FMVSS No. 101. Technical 
revisions to FMVSS No. 138 have also been made in light of recent 
amendments to FMVSS No. 101 that have resulted in a change in location 
of the TPMS telltale provisions from Table 2 to Table 1 of that 
standard.
     In this rule, we are amending the regulatory text in FMVSS 
No. 138 to clarify that for a combined low tire pressure/TPMS 
malfunction indicator telltale, the same flashing/continuous-
illumination sequence is required for one or more malfunctions that may 
affect the system simultaneously.
     The agency has decided to modify the standard's test 
procedures to reduce the current 2-psi pressure adjustment (below the 
TPMS activation threshold) to 1 psi. The 2-psi adjustment was intended 
to facilitate testing, but several petitioners expressed concern that a 
2-psi adjustment could allow TPMSs to achieve compliance with an under-
inflation detection capability of 30 percent or more. The agency 
anticipates that a 1-psi adjustment would continue to facilitate 
testing while maintaining the under-inflation level close to the 
standard's 25-percent under-inflation activation threshold.
     In order to more clearly differentiate between the TPMS 
standard's two phase-in production periods which are of different 
lengths (i.e., almost 11 months vs. one year), we have decided to 
modify 49 CFR 585.66, Reporting Requirements, to differentiate the 
reports to be submitted to the agency for each of the two phase-in 
periods. As currently drafted, section 585.66(b)(1), Basis for 
Statement of Compliance, and section 585.66(b)(2), Production, require 
manufacturers to report values for the full production year, without 
mention of the period corresponding to the first period of the phase-in 
(i.e., from October 5, 2005 to September 1, 2006), which is the 
relevant total production value for calculation under S7.1(b) of FMVSS 
No. 138. Because the reporting of this information directly relates to 
determining compliance with the requirements of FMVSS No. 138, we have 
decided to revise 49 CFR 585.66(b)(1) and (2) to clearly differentiate 
between the two phase-in production periods.

II. Background

A. The TREAD Act

    Congress enacted the Transportation Recall Enhancement, 
Accountability, and Documentation (TREAD) Act of 2000 \2\ on November 
1, 2000. Section 13 of that Act \3\ required the Secretary of 
Transportation, within one year of the statute's enactment, to complete 
a rulemaking ``to require a warning system in new motor vehicles to 
indicate to the operator when a tire is significantly under inflated.'' 
Section 13 also required the regulation to take effect within two years 
of the completion of the rulemaking. Responsibility for this rulemaking 
was delegated to NHTSA.
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    \2\ Public Law 106-414, 114 Stat. 1800 (2000).
    \3\ See 49 U.S.C. 30123 note (2003).
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B. Rulemaking History Prior to the April 2005 Final Rule

    Since passage of the TREAD Act, FMVSS No. 138 has had a protracted 
regulatory history. In summary, the agency published a notice of 
proposed rulemaking (NPRM) \4\ on July 26, 2001, which was followed by 
a final rule \5\ published on June 5, 2002.
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    \4\ 66 FR 38982 (July 26, 2001) (Docket No. NHTSA-2000-8572-30).
    \5\ 67 FR 38704 (June 5, 2002) (Docket No. NHTSA-2000-8572-219).
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    After issuance of the June 2002 final rule, Public Citizen, Inc., 
New York Public Interest Research Group, and the Center for Auto Safety 
filed a suit challenging certain aspects of the TPMS regulation. The 
Court of Appeals for the Second Circuit (Second Circuit) issued its 
opinion in Public Citizen, Inc. v. Mineta \6\ on August 6, 2003. The 
Court found that the TREAD Act unambiguously mandates TPMSs capable of 
monitoring each tire up to a total of four tires, effectively 
precluding the one-tire, 30-percent under-inflation detection option in 
the June 5, 2002 final rule, or any similar option for a system that 
cannot detect under-inflation in any combination of tires up to four 
tires. Ultimately, the Court vacated the standard in its entirety and 
directed the agency to issue a new rule consistent with its August 6, 
2003 opinion. NHTSA published a final rule in the Federal Register on 
November 20, 2003, vacating FMVSS No. 138.\7\
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    \6\ 340 F.3d 39 (2d Cir. 2003).
    \7\ 68 FR 65404 (Nov. 20, 2003) (Docket No. NHTSA-2003-16524-1).
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    The agency commenced rulemaking efforts to re-establish FMVSS No. 
138 in a manner consistent with the Court's opinion and responsive to 
issues raised in earlier petitions for reconsideration, the majority of 
which remained relevant. To this end, the agency published a new NPRM 
\8\ on September 16, 2004.
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    \8\ 69 FR 55896 (Sept. 16, 2004) (Docket No. NHTSA-2004-19054-
1).

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[[Page 53081]]

    After carefully considering public comments on the NPRM, the agency 
published a final rule \9\ in the Federal Register on April 8, 2005, 
which re-established FMVSS No. 138, with a phase-in set to begin on 
October 5, 2005. (For a more complete discussion of this earlier period 
of the regulatory history of the TPMS rulemaking, readers should 
consult the June 5, 2002 final rule, the September 16, 2004 NPRM, and 
the April 8, 2005 final rule.)
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    \9\ 70 FR 18136 (April 5, 2005) (Docket No. NHTSA-2005-20586-1).
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C. The April 8, 2005 Final Rule

    As noted above, the April 8, 2005 final rule for TPMS re-
established FMVSS No. 138 in a manner consistent with the Second 
Circuit's opinion. Specifically, it requires passenger cars, multi-
purpose passenger vehicles, trucks, and buses with a GVWR of 4,536 kg 
(10,000 pounds) or less, except those with dual wheels on an axle, to 
be equipped with a TPMS to alert the driver when one or more of the 
vehicle's tires, up to all four of its tires, is significantly under-
inflated.\10\ Subject to the phase-in schedule and the exceptions 
below, the final rule mandated compliance with the requirements of the 
standard, commencing with covered vehicles manufactured on or after 
October 5, 2005 (i.e., MY 2006). The standard is intended to be 
technology-neutral, so as to permit compliance with any available TPMS 
technology that meets the standard's performance requirements.
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    \10\ There are two types of TPMSs currently available, direct 
TPMSs and indirect TPMSs. Direct TPMSs have a pressure sensor in 
each wheel that transmits pressure information to a receiver. In 
contrast, indirect TPMSs do not have tire pressure sensors, but 
instead rely on the wheel speed sensors, typically a component of an 
anti-lock braking system, to detect and compare differences in the 
rotational speed of a vehicle's wheels, which correlate to 
differences in tire pressure.
    We anticipate that new types of TPMS technology may be developed 
in the future that will be capable of meeting the standard's 
requirements. For example, such systems might incorporate aspects of 
both direct and indirect TPMSs (i.e., hybrid systems). In concert 
with TPMS suppliers, tire manufacturers might be able to incorporate 
TPMS sensors directly into the tires themselves. In issuing a 
performance standard, NHTSA is cognizant of and seeks to encourage 
technological innovation.
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    The following points highlight the key provisions of the April 8, 
2005 final rule.
     The TPMS is required to detect and to provide a warning to 
the driver within 20 minutes of when the pressure of one or more of the 
vehicle's tires, up to a total of four tires, is 25 percent or more 
below the vehicle manufacturer's recommended cold inflation pressure 
for the tires, or a minimum level of pressure specified in the 
standard, whichever pressure is higher. These minimum activation 
pressures are included in Table 1 of FMVSS No. 138.
     Vehicle manufacturers must certify vehicle compliance 
under the standard with the tires installed on the vehicle at the time 
of initial vehicle sale.\11\
     The TPMS must include a low tire pressure warning telltale 
\12\ (yellow) that must remain illuminated as long as any of the 
vehicle's tires remain significantly under-inflated and the vehicle's 
ignition locking system is in the ``On'' (``Run'') position.\13\ The 
TPMS's low tire pressure warning telltale must perform a bulb-check at 
vehicle start-up.
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    \11\ We note that some vehicle manufacturers authorize their 
dealers to replace the vehicle's factory-installed tires with other 
tires, including ones with a different size and/or recommended cold 
tire inflation pressure. The TPMS must perform properly with any 
such tires, because the vehicle could be equipped with those tires 
at the time of initial sale. Of course, the manufacturer would not 
have that responsibility if the dealer installed other tires without 
manufacturer authorization.
    \12\ As part of this final rule, we added two versions of the 
TPMS low tire pressure telltale and a TPMS malfunction telltale to 
Table 2 of FMVSS No. 101, Controls and Displays (since changed to 
Table 1).
    \13\ We note that if a vehicle manufacturer elects to install a 
low tire pressure telltale that indicates which tire is under-
inflated, the telltale must correctly identify the under-inflated 
tire. (See S4.3.2, as contained in the April 8, 2005 final rule.)
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     The TPMS must also include a TPMS malfunction indicator to 
alert the driver when the system is non-operational, and thus unable to 
provide the required low tire pressure warning.\14\ The TPMS 
malfunction indicator must detect a malfunction within 20 minutes of 
occurrence of a system malfunction and provide a warning to the driver. 
This final rule provided two options by which vehicle manufacturers may 
indicate a TPMS malfunction:
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    \14\ We note that the TPMS telltale(s) may be incorporated as 
part of a reconfigurable display, provided that all requirements of 
the standard are met.
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    (1) Installation of a separate, dedicated telltale (yellow) that 
illuminates upon detection of the malfunction and remains continuously 
illuminated as long as the ignition locking system is in the ``On'' 
(``Run'') position and the situation causing the malfunction remains 
uncorrected, or
    (2) Designing the low tire pressure telltale so that it flashes for 
a period of at least 60 seconds and no longer than 90 seconds when a 
malfunction is detected, after which the telltale must remain 
continuously illuminated as long as the ignition locking system is in 
the ``On'' (``Run'') position. This flashing and illumination sequence 
must be repeated upon each subsequent vehicle start-up until the 
situation causing the malfunction has been corrected.
    If the option for a separate telltale is selected, the TPMS 
malfunction telltale must perform a bulb-check at vehicle start-up.
     The TPMS is not required to monitor the spare tire (if 
provided), either when it is stowed or when it is installed on the 
vehicle.
     For vehicles certified under the standard, vehicle 
manufacturers must provide in the owner's manual a specified statement 
explaining the purpose of the low tire pressure warning telltale, the 
potential consequences of significantly under-inflated tires, the 
meaning of the telltale when it is illuminated, and what actions 
drivers should take when the telltale is illuminated. Vehicle 
manufacturers also must provide a specified statement in the owner's 
manual regarding: (1) Potential problems related to compatibility 
between the vehicle's TPMS and various replacement or alternate tires 
and wheels, and (2) the presence and operation of the TPMS malfunction 
indicator. For vehicles that do not come with an owner's manual, the 
required information must be provided in writing to the first purchaser 
at the time of initial vehicle sale.
    In terms of the timing for compliance, the final rule provided as 
follows. Subject to the vehicle manufacturer option for carry-backward 
credits discussed below, NHTSA decided to adopt the following phase-in 
schedule: 20 percent of a vehicle manufacturer's light vehicles are 
required to comply with the standard during the period from October 5, 
2005 to August 31, 2006; 70 percent during the period from September 1, 
2006 to August 31, 2007, and all light vehicles thereafter. Vehicle 
manufacturers are not required to comply with the requirements related 
to the TPMS malfunction indicator (including associated owner's manual 
requirements) until September 1, 2007; however, at that point, all 
covered vehicles must meet all relevant requirements of the standard 
(i.e., no additional phase-in for MIL requirements). The final rule 
included phase-in reporting requirements consistent with the phase-in 
schedule discussed above.
    Small volume manufacturers (i.e., those manufacturers producing 
fewer than 5,000 vehicles for sale in the U.S. per year during the 
phase-in period) are not subject to the phase-in requirements, but 
their vehicles must meet the requirements of the standard beginning 
September 1, 2007.

[[Page 53082]]

    Consistent with the policy set forth in NHTSA's February 14, 2005 
final rule \15\ on certification requirements for vehicles built in two 
or more stages and altered vehicles, final-stage manufacturers and 
alterers must certify compliance for all covered vehicles manufactured 
on or after September 1, 2008 (no phase-in). However, final-stage 
manufacturers and alterers may voluntarily certify compliance with the 
standard prior to this date.
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    \15\ 70 FR 7414 (Feb. 14, 2005) (Docket No. NHTSA-1999-5673-54).
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    NHTSA decided to permit vehicle manufacturers to earn carry-forward 
credits for compliant vehicles, produced in excess of the phase-in 
requirements and manufactured between the effective date of this rule 
and the conclusion of the phase-in. These carry-forward credits could 
be used during the phase-in, but they could not be used to delay 
compliance certification for vehicles produced after the conclusion of 
the phase-in. Except for vehicles produced by final-stage manufacturers 
and alterers (who receive an additional year for compliance), all 
covered vehicles must comply with FMVSS No. 138 on September 1, 2007, 
without use of any carry-forward credits.
    To further ease implementation, we decided to also provide carry-
backward credits, whereby vehicle manufacturers may defer compliance 
with a part or all of the certification requirements for the first 
period of the phase-in, provided that they certify a correspondingly 
larger percentage of vehicles under the standard during the second 
period of the phase-in.

III. Petitions for Reconsideration

    NHTSA received a total of 17 petitions for reconsideration of the 
April 8, 2005 final rule from: (1) The Alliance of Automobile 
Manufacturers (Alliance); (2) the Association of International 
Automobile Manufacturers, Inc. (AIAM); (3) BMW Group (BMW); (4) 
Continental Teves, Inc.; (5) EnTire Solutions, LLC (EnTire); (6) ETV 
Corporation Pty Limited (ETV); (7) European Tyre and Rim Technical 
Organisation (ETRTO); (8) Michelin North America, Inc. (Michelin); (9) 
M-Vision, Inc.; (10) NIRA Dynamics AB; (11) Public Citizen; (12) Rubber 
Manufacturers Association (RMA); (13) SmarTire Systems, Inc. 
(SmarTire); (14) Specialty Equipment Market Association (SEMA); (15) 
Sumitomo Rubber Industries (SRI); (16) Tire Industry Association (TIA); 
and (17) Volkswagen/Audi (VW/Audi). All of these petitions may be found 
in Docket No. NHTSA-2005-20586. (We note that Public Citizen withdrew 
its petition for reconsideration in a letter dated June 16, 2005,\16\ 
and TIA withdrew its petition for reconsideration in a letter dated 
July 28, 2005.\17\ Consequently, we are not discussing these two 
petitions further in this document.)
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    \16\ Docket No. NHTSA-2005-20586-31.
    \17\ Docket No. NHTSA-2005-20586-35.
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    The petitioners raised a variety of issues related to the TPMS 
standard, most of which were technical. These issues included ones 
involving the final rule's requirements for the under-inflation 
detection level, the under-inflation and malfunction detection times, 
functioning of the TPMS with spare tires, tire reserve load, compliance 
testing conditions and procedures, system disablement and 
reprogrammability, telltale issues, breadth of the malfunction 
detection requirement, minimum activation pressure, owner's manual 
requirements, sharing of TPMS servicing information, and phase-in 
calculations.
    All of the issues raised in the petitions for reconsideration 
presently before us are addressed in the Discussion and Analysis 
section immediately below.
    Effective Date. In light of the rapidly approaching October 5, 2005 
start of the phase-in for FMVSS No. 138, we find that there is good 
cause to make these amendments effective 30 days after publication. The 
changes resulting from this final rule responding to petitions for 
reconsideration generally involve requested technical modifications and 
clarifications to the standard. We believe that vehicle manufacturers 
and other interested stakeholders would benefit from rapid 
implementation of these amendments. We note, however, that vehicle 
manufacturers may voluntarily comply with the requirements of this 
final rule immediately.

IV. Discussion and Analysis

A. Low Tire Pressure Warning Lamp Activation Requirements

    The April 8, 2005 final rule required that each TPMS-equipped 
vehicle must illuminate a low tire pressure warning telltale not more 
than 20 minutes after the inflation pressure in one or more of the 
vehicle's tires, up to a total of four tires, is equal to or less than 
either the pressure 25 percent below the vehicle manufacturer's 
recommended cold inflation pressure, or the pressure specified in the 
third column of Table 1 of the standard for the corresponding type of 
tire, whichever is higher. The low pressure telltale must continue to 
illuminate as long as the inflation pressure of the tire(s) remains 
below the activation threshold above and the ignition locking system is 
in the ``On'' (``Run'') position, or until the system is manually reset 
in accordance with the vehicle manufacturer's instructions. (See S4.2, 
as contained in the April 8, 2005 final rule.)
    Several petitioners requested that the agency modify the time 
period for the TPMS to detect and to provide a warning regarding 
significant under-inflation in one or more of a vehicle's tires. Some 
petitioners recommended a reduction in detection time (ETRTO, SmarTire 
Systems, ETV); others sought an increase in such time period (NIRA 
Dynamics, VW/Audi), and still another argued for some combination of 
the two (BMW).
    ETRTO argued that the decision in the final rule to set a 20-minute 
detection time requirement for the TPMS low tire pressure warning (an 
increase from the 10-minute detection time proposed in the NPRM) may 
compromise safety, because driving for an additional 10 minutes on a 
significantly under-inflated tire could cause that tire to further 
deflate, overheat, and fail. ETRTO cautioned that ``technical 
neutrality'' should not be permitted to surpass safety concerns. 
Accordingly, the ETRTO petition urged NHTSA to adopt an under-inflation 
detection time of 10 minutes, as proposed in the NPRM. ETRTO did not 
provide supporting data to demonstrate the extent of tire degradation 
that would result from the under-inflation detection time adopted in 
the final rule.
    In its petition, SmarTire Systems argued that repeated exposure of 
a tire to excessive heat build-up could cause cumulative deterioration 
of the tire's structural components, which could ultimately lead to 
tire failure. SmarTire Systems provided data intended to show that 
within 12 minutes of city driving (at approximately 30 mph) at a low 
ambient temperature, pressure build-up within a properly inflated tire 
is about 3 psi, resulting from temperature build-up within the tire. 
According to the petitioner, the longer detection time interval may 
exacerbate this phenomenon and could actually mask an under-inflation 
condition. SmarTire Systems argued that this situation potentially 
could have unintended consequences for testing, as well as negative 
safety implications. As a result, SmarTire Systems also recommended 
that the standard be modified to return to a 10-minute under-inflation 
time requirement, as originally proposed.

[[Page 53083]]

    ETV argued that in order to maximize safety, the standard should be 
amended to require a TPMS to detect low tire pressure and to provide a 
warning immediately upon vehicle start-up. In making this argument, ETV 
analogized to other vehicle safety systems (e.g., air bags, ABS/brakes, 
seat belts) that provide a warning while the vehicle is stationary or 
parked (i.e., before the driver moves the vehicle into traffic).
    An opposing viewpoint was presented in the petition submitted by 
NIRA Dynamics, which argued that the 20-minute under-inflation 
detection time for more than one tire is unnecessarily stringent in 
light of the circumstances that normally cause multiple-tire under-
inflation. According to the petitioner, under-inflation in multiple 
tires usually results from slow diffusion over many months (loss of 1-2 
psi per month), so 20-minute time requirements for TPMS calibration and 
under-inflation detection are not necessary. NIRA Dynamics also stated 
that indirect TPMSs update actual parameter values whenever a vehicle 
is driven (storing the latest values in memory when the engine is 
turned off). Therefore, the TPMS telltale would be expected to 
illuminate, regardless of the length of the last driving cycle, as soon 
as the accumulated driving time with an under-inflated tire is 
sufficiently long. Accordingly, NIRA Dynamics recommended that NHTSA 
increase the time period permitted for TPMS calibration and low 
pressure detection for multiple tires to one hour. The petitioner 
stated that such a change would permit the use of advanced indirect 
TPMS technologies, while maintaining the safety benefits of the 
standard. The petition of VW/Audi made an argument very similar to that 
of NIRA Dynamics on this point.
    BMW also expressed its expectation that a TPMS-equipped vehicle 
would not need to be driven continuously during a single trip in order 
to detect low tire pressure, but instead, cumulative driving time 
gathered over a number of shorter trips should be adequate to detect 
and warn about significant tire under-inflation. Therefore, BMW 
reasoned that the TPMS would be unlikely to need the fully allotted 
detection time in most cases.
    However, BMW recommended a slightly different solution from that 
proposed by NIRA Dynamics and VW/Audi. Specifically, BMW stated that 
NHTSA should revise the standard to require a 10-minute cumulative 
driving detection time for pressure loss in a single tire and a 60-
minute cumulative driving detection time for pressure loss in multiple 
tires, an approach that it believes would offer an equivalent or higher 
level of safety than the approach adopted in the final rule. 
Alternatively, BMW suggested that its approach be adopted as an 
optional means of compliance. BMW argued that its requested change also 
would make the standard more technology-neutral, because it stated that 
there are not any ``production-ready'' indirect TPMSs that can meet the 
standard's 20-minute detection requirement under all circumstances.
    NHTSA has carefully considered the arguments of petitioners seeking 
modifications to the standard's low tire pressure warning lamp 
activation requirements. In general, the petitioners reiterated 
arguments raised at previous stages of this rulemaking and did not 
provide any new information to support their positions. Thus, we have 
decided to retain the low tire pressure activation requirements 
(including those related to system calibration) set forth in the April 
8, 2005 final rule. Our reasoning is largely the same as expressed in 
that notice, which we summarize below.
    We continue to believe that a 20-minute time period for under-
inflation detection in one to four tires is appropriate, as is a 20-
minute time period for TPMS calibration. The low tire pressure lamp 
activation requirements reflect the agency's careful balancing of 
safety and practicability concerns viewed through the prism of 
available data.
    As we noted in the final rule, TPMSs were not developed to warn the 
driver of extremely rapid pressure losses that could accompany a 
vehicle encounter with a road hazard or a tire blowout. According to 
the tire industry, those types of events account for approximately 15 
percent of pressure loss cases.\18\ Presumably, a driver would be well 
aware of the tire problem in those situations, and the TPMS would 
provide little added benefit.
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    \18\ 67 FR 38704, 38728 (June 5, 2002) (Docket No. NHTSA-2000-
8572-219).
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    Instead, TPMSs' benefits lie in warning drivers when the pressure 
in the vehicle's tires is approaching a level at which permanent tire 
damage could be sustained as a result of heat buildup and tire failure 
is possible; this low level of inflation pressure generally results 
from a more measured pressure loss cause by a slow leak, defective 
valve, or diffusion. According to the tire industry, approximately 85 
percent of all tire pressure losses are slow air losses that occur over 
hours, weeks, or months of vehicle use.\19\ In those cases, a detection 
time of 20 minutes is not likely to pose a safety risk to the driving 
public.
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    \19\ Id.
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    The agency's tire research suggests that even in a 25-percent 
under-inflated condition, the vehicle can be operated safely for this 
detection period without an appreciable risk of permanent damage or 
tire failure. NHTSA conducted testing on a variety of Standard Load P-
metric tires at 20 psi with 100-percent load at 75 mph for 90 minutes 
on a dynamometer, and none of these tires failed.\20\ This testing led 
the agency to conclude that warnings at less severe conditions will 
give drivers sufficient time to check and re-inflate their vehicles' 
tires before the tires experience appreciable damage. Furthermore, 
analysis of public comments at the NPRM stage demonstrated that a 
detection time period shorter than 20 minutes could raise issues of 
detection accuracy for many systems, which could lead to false telltale 
illuminations (``nuisance warnings''), which in turn could negatively 
impact consumer acceptance of TPMSs.
---------------------------------------------------------------------------

    \20\ Id. at 38726.
---------------------------------------------------------------------------

    Petitioners advocating a shorter time period did not provide any 
countervailing data to substantiate their assertions that a 20-minute 
detection time for a significantly under-inflated tire would lead to 
tire damage or tire failure. Although manufacturers are encouraged to 
provide the low tire pressure warning as quickly as possible, we 
believe that a 20-minute detection time is unlikely to result in any 
adverse safety consequences.
    We also believe that a 20-minute detection time is consistent with 
our intention to articulate a standard that is practicable and 
technology-neutral. As noted in the final rule, we are aware of at 
least one indirect TPMS that is currently capable of meeting the 
standard's four-tire, 25-percent under-inflation detection requirement 
within 20 minutes,\21\ and we expect that with additional time and 
development, other indirect and hybrid systems also would be able to 
meet the requirements of the standard.
---------------------------------------------------------------------------

    \21\ Docket No. NHTSA-2004-19054-96.
---------------------------------------------------------------------------

    We are not adopting ETRTO's and SmarTire's recommendations to 
reduce the time period for under-inflation detection time to 10 minutes 
because our tire data suggest that such change is not required for 
safety and because it would likely decrease the number of technologies 
available for complying with the standard. The same reasoning applies 
to our decision to deny ETV's suggestion that the TPMS be required to

[[Page 53084]]

provide a low tire pressure warning upon vehicle start-up (i.e., before 
the vehicle is in motion).
    Furthermore, we have decided not to extend the low tire pressure 
detection time beyond 20 minutes for multiple-tire under-inflation, as 
requested by NIRA Dynamics, VW/Audi, and BMW. As explained in the final 
rule, we believe that adverse safety consequences could result if the 
low tire under-inflation detection time were to extend beyond 20 
minutes. As discussed in the final rule, available research suggests 
that average commuting times are less than 30 minutes in most 
cases.\22\ Many other trips, such as routine errands, may also involve 
drive times of less than 30 minutes. We expressed concerns that by 
increasing the low tire pressure detection time, it would be 
conceivable that consumers could be driving on significantly under-
inflated tires for a potentially extended period of time without 
receiving a warning from the TPMS.
---------------------------------------------------------------------------

    \22\ 70 FR 18136, 18148 (April 8, 2005) (Docket No. NHTSA-2005-
20586-1).
---------------------------------------------------------------------------

    We also expressed concern that extending the low tire pressure 
detection time beyond 20 minutes could be problematic in other 
situations. For example, where a tire is punctured by a nail or is 
otherwise damaged, it may experience a moderately rapid pressure loss. 
As to damaged tires experiencing a relatively less rapid pressure loss, 
research into the rate of temperature buildup shows that for constant 
load, pressure, and speed conditions, tires generally warmed up and 
stabilized their temperatures within 15 minutes; \23\ thus, the tire 
will rapidly reach a temperature that places stress on an under-
inflated tire. In such cases, we are concerned about delaying the 
warning to the driver for too long. Therefore, in the April 8, 2005 
final rule, we selected 20 minutes for the low tire pressure detection 
time, because we believed that it would maintain the utility of the 
TPMS and the safety benefits associated with that system.
---------------------------------------------------------------------------

    \23\ See June 5, 2002 comments of the RMA (Docket No. NHTSA-
2000-8011-64).
---------------------------------------------------------------------------

    We do not believe that the arguments presented by BMW and NIRA 
Dynamics regarding the cumulative nature of data gathering by the TPMS 
justifies changing the standard's low tire pressure detection time to 
one hour for multiple tires. We believe that a one-hour delay in 
warning the driver of significant tire under-inflation either when the 
system is new, reset, or reprogrammed is too long, particularly given 
that other systems can provide a warning more rapidly. BMW and NIRA 
Dynamics did not provide any data indicating that tires could be 
operated safely for one hour after reaching a level of inflation that 
is 25 percent below placard pressure. Thus, we are concerned that an 
increase in the detection time for multiple-tire under-inflation could 
decrease the safety benefits of the rule. The same logic applies to 
BMW's suggestion that the time for malfunction detection be increased 
to one hour, a request that we are also denying, because a 
malfunctioning TPMS may not be available to warn about a concurrent 
tire under-inflation problem.

B. TPMS Malfunction Indicator Lamp (MIL) Activation Requirements

1. What Constitutes a TPMS Malfunction?
    As part of the final rule establishing FMVSS No. 138, the TPMS-
equipped vehicle's MIL telltale must provide a warning to the driver 
not more than 20 minutes after the occurrence of a malfunction that 
affects the generation or transmission of control or response signals 
in the vehicle's TPMS. (See S4.4, as contained in the April 8, 2005 
final rule.) Paragraph S6(k) of the final rule's test procedures 
provides for the simulation of one or more TPMS malfunction(s) by 
disconnecting any electrical connection between TPMS components, or by 
installing a tire or wheel on the vehicle that is incompatible with the 
TPMS.
    The details as to exactly what constitutes a TPMS malfunction were 
among the most extensively discussed issues in the petitions for 
reconsideration. Many petitioners who discussed this issue generally 
sought clarification regarding whether a malfunction warning would be 
required under specific situations. The malfunction-related issues 
raised in these petitions are addressed below.
    The AIAM recommended amending S4.4(a) to narrow the definition of 
``TPMS malfunction'' to limit that term to conditions where proper 
power supply is maintained to the TPMS. According to the AIAM petition, 
the standard, as currently written, would require installation of 
another electronic control module (ECM) in addition to the TPMS ECM in 
order to solely monitor MIL telltale operations, a largely redundant 
feature that would use up limited space behind the dashboard.
    As its recommended solution, the AIAM recommended that the scope of 
S4.4(a) be limited to situations where the TPMS has power, which would 
allow the system to identify malfunctions in the TPMS ECM and 
components such as the wheel sensors, signal antennae, or the presence 
of incompatible tires. In its petition, the AIAM argued that an 
interruption of power to the ECM or to the telltale (or to the 
connection between the ECM and the telltale) would be identifiable by 
failure to illuminate the TPMS MIL during bulb check. The AIAM also 
recommended modifying S6(l) to incorporate these conditions or by 
having S6(k) exclude these conditions from the procedures for creating 
a simulated TPMS malfunction.
    The Alliance similarly argued in its petition that NHTSA should 
clarify that S6(k) of the test procedures, which permits 
``disconnecting the power source to any TPMS component,'' should not 
include disconnecting the power source to the telltale itself. The 
Alliance stated its belief that the telltale is an FMVSS No. 101 
component (not a ``TPMS component''), and that the situation where 
there is a loss of power to the telltale is already covered by the bulb 
check requirements in S4.3.3(a) or S4.4(b)(4)(i), thereby obviating the 
need for it to be covered under S4.4(a).
    The Alliance also recommended a minor editorial change in 
S4.4(b)(3) that would modify that provision to read as follows: 
``Continues to illuminate the TPMS malfunction telltale under the 
conditions specified in S4.4(a) * * *.'' The standard currently 
references ``S4.4.''
    EnTire Solutions argued that for TPMSs using Hardwired Vehicle 
Speed Input to the TPMS receiver, such input does not directly affect 
``the generation or transmission of control or response signals'' in 
the vehicle's TPMS, and disconnecting vehicle speed input would not 
involve an electrical connection between ``TPMS components'' as called 
out specifically in S6(k) of the FMVSS No. 138 test procedures. 
According to EnTire Solutions, disconnecting vehicle speed input is 
``impractical'' to diagnose since such a disconnect would not prevent 
the TPMS from providing under-inflation warnings while driving unless 
there are multiple problems with the system. Accordingly, EnTire 
Solutions requested clarification as to whether systems using Hardwired 
Vehicle Speed Inputs need to illuminate the TPMS MIL telltale upon 
disconnection of those inputs.
    EnTire Solutions also requested a clarification regarding paragraph 
S6(k) of the TPMS test procedures, which provides an instruction 
regarding ``disconnecting any electrical connection between TPMS 
components * * *.'' Specifically, the petitioner questioned whether the 
above language

[[Page 53085]]

refers to connector-level interconnects or individual wires.
    In its petition, EnTire Solutions stated that for systems using 
multiple ground paths for the receiver, it is ``impractical'' to 
diagnose a single ground path disconnection. EnTire Solutions 
recommended that the standard be amended to clarify that TPMS MIL 
activation will not be required in such cases. EnTire Solutions also 
asked if the system could be constructed such that the low pressure 
detection lamp could be illuminated by an auxiliary power source when 
the primary source is disconnected without illuminating the MIL. This 
question applies to low tire pressure telltales that indicate which 
tire is under-inflated and telltales that do not indicate which tire is 
under-inflated (i.e., the ISO lamp).
    NIRA Dynamics' petition argued that it is not possible for vehicle 
manufacturers to meet the final rule's certification requirement for 
the TPMS to be able to detect all replacement tires that are not 
compatible with the system, because it is not possible to know what 
tires will be offered in the future or how such tires will interact 
with current TPMSs. According to NIRA Dynamics, to make such a 
certification, vehicle manufacturers installing indirect TPMSs would be 
required to test their systems with all types of tires available on the 
market, both now and in the future, something which would not be 
possible for economic and practical reasons. Therefore, the petitioner 
recommended amending the final rule to state that the TPMS MIL 
requirements are limited to electrical and system transmission 
interruptions or failures that result in no sensor signal being sent to 
the TPMS control module.
    In its petition, SRI argued that there are other conditions, albeit 
rare, that could affect the performance of TPMSs even if the control or 
response signals are properly transmitted. For example, SRI stated that 
a direct TPMS may not recognize that it is transmitting incorrect 
pressure data due to a sensor failure, or an indirect TPMS may not 
recognize that the sensitivity of the TPMS is lower due to certain tire 
characteristics. SRI essentially agreed with the argument of NIRA 
Dynamics, arguing that analyzing the influence of all replacement tires 
on the TPMS would be just as difficult as requiring that the TPMS be 
compliant with all replacement tires.
    M-Vision's petition questioned whether the standard's requirements 
for malfunction detection would include instances where there is a 
mechanical failure of the TPMS, including ones resulting from a 
separation of the joint/mount between the sensor assembly and the 
wheel, or separation of parts from the sensor assembly. According to M-
Vision, a typical TPMS sensor weighs about 40 grams (1.41 ounces), and 
if such components come loose as a result of fatigue, they may generate 
high g-forces, cause internal damage to the tire, and ultimately lead 
to tire failure. The M-Vision petition also argued that a loose TPMS 
device rattling within the front wheel could lead to sudden wheel 
imbalance while the vehicle is in motion, potentially causing the 
driver to steer improperly. In order to prevent what it deems to be a 
significant safety risk, M-Vision recommended that the definition of a 
``TPMS malfunction'' be modified to include mechanical failures, as 
described in its petition.
    Continental Teves' petition requested clarification of that portion 
of S4.4(a), which requires the TPMS MIL to illuminate ``not more than 
20 minutes after occurrence of a malfunction that affects the 
generation of transmission of control or response signals in the 
vehicle's tire pressure monitoring system.'' (Emphasis added.) We 
understand Continental Teves to be arguing that there are other 
circumstances or factors that could ``affect'' the system (e.g., 
replacement tire construction) without preventing it from detecting and 
providing the requisite low tire pressure warning. Therefore, 
Continental Teves recommended changing the word ``affects'' to 
``inhibits'' in S4.4(a), which it argued is consistent with the purpose 
of the TPMS MIL to alert the driver when the system is not functional.
    Given that the TPMS MIL requirements were a relatively recent 
conceptual addition to FMVSS No. 138, it is not surprising that several 
petitioners requested clarification of those provisions. As noted 
above, such clarification requests included questions of coverage of 
specific potential malfunction, some of which the petitioners asserted 
could be difficult to detect. Our response, addressing these concerns 
about the standard's malfunction requirements, is provided below.
    In overview, we have decided to retain the final rule's requirement 
for the TPMS MIL to illuminate whenever there is a malfunction that 
affects the generation of transmission of control or response signals 
in the vehicle's tire pressure monitoring system. The agency continues 
to favor a broad detection requirement for the TPMS MIL and not one 
limited to specific malfunctions, because such restrictions would 
unnecessarily reduce the safety benefits of the TPMS. However, in 
response to petitions (AIAM, Alliance) and in light of our own prior 
statements, we have decided to amend the standard's test procedures for 
malfunction detection to explicitly state that telltale lamps will not 
be disconnected, because such malfunctions would be indicated during 
the bulb checks required under S4.3.3(a) and/or S4.4(b)(4). 
Consequently, the driver would be provided with information regarding 
the operability of the TPMS warning telltale(s) through alternative 
means.
    We believe that this clarifying change is consistent with the final 
rule. In that notice, we stated that ``the MIL should not be required 
to signal a burned out bulb as a TPMS malfunction, because that problem 
would already be identified during the check-of-lamp function at 
vehicle start-up.'' (70 FR 18136, 18151 (April 8, 2005)) It was not our 
intention to require a redundant system solely to monitor the TPMS 
telltale(s). Similarly, the check-of-lamp function would alert the 
driver of malfunctions pertaining to processes directly tied to 
operation of the TPMS telltale(s) that necessitate servicing. When the 
driver takes the vehicle to the repair facility, the problem should be 
diagnosed and corrected, even though it may not be the one anticipated 
(e.g., a problem with a wire rather than a burned out bulb). Thus, this 
subset of TPMS-related malfunctions would still be expected to be 
identified, but through a mechanism other than the MIL. Accordingly, we 
are amending S6(k) to delimit the types of system malfunctions that 
will be simulated during testing, consistent with the above. 
Specifically, we are adding the following statement to that paragraph: 
``When simulating a TPMS malfunction, the electrical connections for 
the telltale lamps shall not be disconnected.''
    Furthermore, in response to EnTire's requests for clarification 
regarding specific potential disconnections, we have decided that all 
electrically-powered components and devices that interface with the 
TPMS, including hardwired vehicle speed inputs, are potential 
candidates for disconnection under S6(k). Similarly, a single ground 
path in a multiple ground path system may be a candidate for 
disconnection during TPMS malfunction testing.
    We are denying NIRA Dynamics' request that the standard be amended 
to exclude incompatible aftermarket and replacement tires from the 
malfunctions that the TPMS malfunction indicator must be able to 
detect. As noted in the April 8, 2005 final rule, we believe that the 
ability of the TPMS malfunction indicator to detect incompatible tires 
is key to the long-term functionality of the

[[Page 53086]]

TPMS, and unless such a warning is provided, some drivers may lose the 
benefits of the system entirely. It is plainly foreseeable that most 
vehicles will outlast their original set of tires, so this requirement 
is necessary to ensure that consumers continue to receive the TPMS's 
important information related to low tire pressure.
    The petition of NIRA Dynamics did not provide data to demonstrate 
the nature or extent of indirect TPMSs' alleged problems related to 
detection of incompatible tires. We do not believe that manufacturers 
would have to test all tires in order to determine which tires are 
incompatible with a given system, as NIRA Dynamics has suggested. Our 
understanding is that indirect TPMSs detect low tire pressure by 
comparing the differences in the rolling radius of the tires (i.e., 
speed of the tires) and activating the low tire pressure telltale when 
the difference between wheel speeds reaches a certain pre-determined 
value. We further understand that for indirect TPMSs, incompatible 
tires are primarily tires with a relationship between rolling radius 
and tire pressure that is outside the range of the system or where the 
geometry of one tire is outside the tolerances of the system. In such 
cases, the TPMS must be able to distinguish between a tire with low 
pressure and one that is incompatible with the TPMS, and to then 
illuminate the MIL.
    In direct TPMSs, tire incompatibility is primarily associated with 
tire construction materials and their potential attenuation of radio 
frequency signals generated by the TPMS unit (sensor) inside the tire. 
Based upon all available information, we have decided that TPMSs should 
continue to be required to alert the driver of a variety of system 
malfunctions, including installation of incompatible aftermarket or 
replacement tires. We believe that this approach will ensure continued, 
long-term TPMS functionality, which is consistent with Congress' 
intention to improve tire and vehicle safety, as expressed in the TREAD 
Act.
    We have decided not to adopt M-Vision's recommendation that we 
amend the standard's malfunction detection requirement to specifically 
address mechanical failures of the system, such as a separation of 
wheel-mounted TPMS components. We believe that severe mechanical 
failures of TPMS wheel components would trigger the TPMS malfunction 
indicator in most cases, because a severe mechanical problem with a 
sensor would retard communications between the sensor and the receiver. 
In addition, it would be difficult to simulate a mechanical malfunction 
of a wheel component without dismounting the tire from the wheel, and 
potentially damaging the TPMS. Furthermore, we have not been presented 
with any data to demonstrate that mechanical failures, such as those 
described in the M-Vision petition, are likely to arise in actual 
vehicles or the consequences thereof. If situations involving 
mechanical failures of TPMS wheel components were to develop 
frequently, those types of potential TPMS failures may be determined to 
be defects, which would be properly addressed by NHTSA's Office of 
Defects Investigation.
    Regarding Continental Teves' recommendation for a wording change 
under the standard's malfunction detection requirement (S4.4), 
specifically to state that a malfunction ``inhibits'' rather than 
``affects'' the generation or transmission of control or response 
signals in the vehicle's TPMS, we have decided to deny that request. 
Overall, the rationale offered by Continental Teves in support of its 
recommended change to the definition of a TPMS malfunction was not 
cogent and seemed incomplete. For example, the petition mentioned a 
hybrid system, but it did not explain how it operates. We do not 
believe that the Continental Teves petition provides a sufficient basis 
to support its recommended change to the standard.
    We have decided to grant the Alliance's request for a technical 
change in S4.4(b)(3) that would modify that provision to read as 
follows: ``Continues to illuminate the TPMS malfunction telltale under 
the conditions specified in S4.4(a) * * *.'' Although we do not believe 
that the standard's current reference to S4.4 in that provision is 
likely to cause any confusion or additional burden, we agree that the 
Alliance's recommended specification is more precise.
2. MIL Disablement
    The final rule did not contain any provision for MIL disablement, 
and the preamble discussed the agency's rationale for not permitting 
system disablement (see section IV.C.2(c), as contained in the April 8, 
2005 final rule).
    In its petition, SEMA expressed support for the agency's decision 
in the final rule not to permit disablement of the TPMS malfunction 
indicator lamp. However, SEMA requested clarification as to whether the 
MIL may be disabled (made inoperative) for the purpose of replacing the 
TPMS with an equivalent aftermarket TPMS that also meets the 
requirements of the FMVSS No. 138. For example, SEMA suggested that a 
consumer may wish to ``upgrade'' the vehicle's TPMS in situations where 
that person encounters incompatible replacement tires. If disablement 
of the MIL were permitted for such replacement purpose, SEMA argues 
that it would alleviate SEMA's concerns that consumers will choose not 
to install aftermarket or replacement rims and tires because they would 
lose the benefits of the MIL or have to accept driving with the MIL 
illuminated. Thus, SEMA recommended that NHTSA clarify that it is 
permissible to make the TPMS inoperative in order to replace the system 
with another TPMS that is also compliant with FMVSS No. 138.
    We do not believe that it is necessary to amend the TPMS standard 
in order to permit suppliers and service technicians to install 
aftermarket components and systems that comply with FMVSS No. 138. This 
principle holds for our safety standards generally. We believe this 
approach is appropriate for the following reasons.
    By way of background, the disablement for repair/replacement 
concept is addressed in 49 U.S.C. 30122(b), which provides:

    A manufacturer, distributor, dealer, or motor vehicle repair 
business may not knowingly make inoperative any part of a device or 
element of design installed on or in a motor vehicle or motor 
vehicle equipment in compliance with an applicable motor vehicle 
safety standard prescribed under this chapter [49 U.S.C. 30101 et 
seq.] unless the manufacturer, distributor, dealer, or repair 
business reasonably believes the vehicle or equipment will not be 
used (except for testing or a similar purpose during maintenance or 
repair) when the device or element is inoperative.

    When an automotive service business brings a vehicle into its 
facility for repair, replacement, or servicing of vehicle systems or 
components, it stands to reason that certain operating components or 
systems may need to be disabled in order to effectuate those changes. 
Furthermore, while such changes are pending, we expect that the vehicle 
would not be engaged in on-road use. By the time the vehicle is again 
returned to on-road use, the business must ensure that aspects of the 
vehicle covered by applicable FMVSSs have been made inoperative. With 
that proviso, upgrades to the vehicle of the type mentioned by SEMA 
would be permissible, even if the standard does not explicitly state 
it.
C. Telltale Requirements
    The final rule requires each TPMS to include a low tire pressure 
warning telltale that is mounted inside the occupant compartment in 
front of and

[[Page 53087]]

in clear view of the driver and which is identified by one of the 
symbols for the ``Low Tire Pressure Telltale'' in Table 2 of FMVSS No. 
101, Controls and Displays. The low tire pressure warning telltale is 
required to illuminate under the conditions specified in S4.2 of FMVSS 
No. 138, and it must also perform a check of lamp function when the 
ignition locking system is activated to the ``On'' (``Run'') position 
or a position between ``On'' (``Run'') and ``Start'' that is designated 
by the manufacturer as a check position. (See S4.3, as contained in the 
April 8, 2005 final rule.)
    Under the final rule, the TPMS-equipped vehicle is also required to 
be equipped with a TPMS malfunction indicator (beginning September 1, 
2007). This malfunction indicator may be provided either through a 
separate, dedicated telltale or through a combined low tire pressure/
TPMS malfunction telltale. For the separate TPMS MIL, the telltale must 
be mounted inside the occupant compartment in front of and in clear 
view of the driver and be identified by the word ``TPMS,'' as described 
under ``TPMS Malfunction Telltale'' in Table 2 of FMVSS No. 101. The 
dedicated TPMS malfunction telltale is required to illuminate under the 
conditions specified in S4.4 of FMVSS No. 138 for as long as the 
malfunction exists, and it must also perform a check of lamp function 
when the ignition locking system is activated to the ``On'' (``Run'') 
position or a position between ``On'' (``Run'') and ``Start'' that is 
designated by the manufacturer as a check position. (See S4.4(b), as 
contained in the April 8, 2005 final rule.)
    If the vehicle manufacturer elects to provide a combination 
telltale, it must meet the requirements of S4.2 and S4.3, as discussed 
above, and also indicate a TPMS malfunction as follows. While the 
ignition locking system is activated to the ``On'' (``Run'') position, 
upon detection of a TPMS malfunction, the combination telltale must 
flash for a period of at least 60 seconds but no longer than 90 
seconds. After this period of prescribed flashing, the telltale must 
remain continuously illuminated as long as the malfunction exists and 
the ignition locking system is activated to the ``On'' (``Run'') 
position. This flashing and illumination sequence must be repeated each 
time the ignition locking system is activated to the ``On'' (``Run'') 
position until the situation causing the malfunction has been 
corrected. (See S4.4(c), as contained in the April 8, 2005 final rule.)
    As discussed below, the Alliance petition raised issues related to 
the operation of the TPMS related telltale(s), as well as the timing 
for implementing the telltale requirements. More specifically, the 
Alliance's petition sought clarification regarding how a combined TPMS 
telltale should operate when sequential malfunctions occur. The 
Alliance identified the following potential approaches: (1) Have one 
flashing sequence cover all TPMS malfunctions; (2) Have each 
malfunction trigger a separate warning, or (3) Extend the length of the 
flashing sequence to indicate more than one malfunction. The 
recommendation of the Alliance was to leave the choice among these 
approaches to vehicle manufacturer discretion.
    The Alliance also petitioned to correct what it perceives to be a 
lack of synchronization between the TPMS telltale requirements in FMVSS 
No. 138 and in FMVSS No. 101. Specifically, the Alliance stated that 
vehicle manufacturers have no compliance requirements vis-a-vis FMVSS 
No. 138 until October 5, 2005, but there is not any corresponding 
compliance date specified in FMVSS No. 101 regarding the TPMS-related 
symbols (which arguably results in a compliance date of April 8, 2005 
for those telltale symbols). According to the Alliance, failure to 
remedy this apparent oversight would negatively impact the voluntary 
introduction of TPMSs that are not certified to FMVSS No. 138, and the 
Alliance stated that substantial lead time is needed to incorporate 
such display changes. Therefore, the Alliance recommended adding two 
footnotes to Table 2 of FMVSS No. 101 that would exempt vehicles from 
compliance with the TPMS symbol requirements for vehicles whose TPMSs 
are not certified as compliant with FMVSS No. 138 during the phase-in 
period for that standard.\24\
---------------------------------------------------------------------------

    \24\ The Alliance recommended that the following statement be 
added to Footnote 9 of FMVSS No. 101 Table 2: ``Display requirements 
for Tire Pressure Monitoring System Malfunction Telltale are 
effective for vehicles manufactured on or after September 1, 2007.''
---------------------------------------------------------------------------

    The Alliance also recommended adding a new Footnote 10 to that 
table as follows: ``Display requirements of the low tire pressure 
telltale are mandatory only for vehicles compliant with the 
requirements of FMVSS No. 138 at the date of vehicle manufacture.''
    Regarding the issue of sequential (multiple) malfunctions, we have 
decided that for vehicles with a combined low tire pressure/malfunction 
warning indicator, the telltale must flash for a single period of at 
least 60 seconds but no longer than 90 seconds and then remain 
con