General Motors Corporation, Denial of Petition for Decision of Inconsequential Noncompliance, 3765-3766 [05-1433]

Agencies

• National Highway Traffic Safety Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 70, Number 16 (Wednesday, January 26, 2005)]
[Notices]
[Pages 3765-3766]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-1433]


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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

[Docket No. NHTSA 2004-17679; Notice 2]


General Motors Corporation, Denial of Petition for Decision of 
Inconsequential Noncompliance

    General Motors Corporation (GM), has determined that certain 2004 
model year vehicles that it produced do not comply with S5.1 of 49 CFR 
571.124, Federal Motor Vehicle Safety Standard (FMVSS) No. 124, 
``Accelerator control systems.'' Pursuant to 49 U.S.C. 30118(d) and 
30120(h), GM has petitioned for a determination that this noncompliance 
is inconsequential to motor vehicle safety and has filed an appropriate 
report pursuant to 49 CFR part 573, ``Defect and Noncompliance 
Reports.'' Notice of receipt of a petition was published, with a 30-day 
comment period, on May 19, 2004, in the Federal Register (69 FR 28977). 
NHTSA received no comments.
    Approximately 19,924 model year 2004 Cadillac SRX, Cadillac XLR, 
and Pontiac Grand Prix vehicles are affected. S5.1 and S5.3 of FMVSS 
No. 124 require that there shall be at least two sources of energy 
capable of returning the throttle to the idle position from any 
accelerator position or speed whenever the driver removes the opposing 
actuating force. In the event of failure of one source of energy by a 
single severance or disconnection, the return to idle shall occur 
within three seconds for any vehicle that is exposed to ambient air at 
-18 [deg]C to -40 [deg]C.
    However, for the subject vehicles, in the event of failure of 
either of the two Electronic Throttle Control (ETC) Pedal return 
springs at ambient temperatures of -30 [deg]C to -40 [deg]C for the 
Grand Prix and XLR and -10 [deg]C to -40 [deg]C for the SXR, the engine 
in some of these

[[Page 3766]]

vehicles may not return to idle within the time limits specified by 
S5.3.
    GM believes that the noncompliance is inconsequential to motor 
vehicle safety for the following reasons:

    Vehicle Controllability: A number of conditions must occur for 
the noncompliance to occur. A return spring must be severed, the 
stack-up of tolerances in the ETC Pedal Position Sensor must exist, 
the vehicle must have soaked at an ambient temperature of -30[deg] C 
to -40[deg] C for the Grand Prix and XLR and -10 [deg]C to -40 
[deg]C for the SXR, and the customer must drive the vehicle prior to 
the vehicle interior warming up. In the extremely low likelihood of 
all of these conditions existing, the condition would occur upon the 
first application of the throttle pedal. The vehicle would continue 
to be controllable by steering and braking, and the ETC Pedal 
assembly would return to normal operation once the passenger 
compartment warmed up.
    Pedal Assembly is Protected: When FMVSS No. 124 was established 
in 1973, the accelerator control systems of vehicles consisted of a 
mechanical connection between the accelerator pedal and the engine's 
carburetor. The throttle return springs required by FMVSS No. 124 
were typically part of the carburetor, and subject to the harsh 
engine environment. The requirements of S5.1 were established to 
ensure that if one of those springs in that environment were to 
fail, the engine would return to idle in a timely manner.
    The ETC Accelerator Pedal Module in the subject vehicles 
consists of the accelerator pedal at the end of the accelerator 
pedal lever. The lever is connected to the ETC Pedal Sensor shaft, 
and is returned to the idle position by two return springs. The ETC 
Pedal Sensor provides two redundant signals to the engine control 
module to indicate accelerator pedal position. The ETC Accelerator 
Pedal Module is located entirely within the passenger compartment of 
the vehicle. The return springs are in a protected area under the 
instrument panel, and are not subject to the harsh environment of 
the engine compartment.
    Condition Requires Failed Return Spring: The condition that is 
described can only occur if one of the two return springs is severed 
or disconnected. The springs in the subject Accelerator Pedal 
Module, however, have extremely high reliability and are not likely 
to fail in the real world.
    Durability Testing: The ETC Accelerator Pedal Module is designed 
for a service life of at least 100,000 miles or 10 years working 
life for passenger car application. The Minimum Typical Predicted 
Usage Profile of the Component Technical Specification states that 
the Accelerator Pedal mechanism may be subject to 35,000,000 dithers 
/ 70,000,000 sensor direction changes. The GM Test Procedure TP3750, 
Accelerator Pedal Lab Durability Cycling Test, that is used during 
the development and validation of this system, subjects these parts 
to 2 million cycles, an equivalent usage greater than 6 lives for an 
automatic transmission passenger vehicle and 3 lives for a manual 
transmission passenger vehicle. There were no accelerator pedal 
return spring failures after testing multiple samples to 10 million 
cycles during the durability testing that was performed on the ETC 
Accelerator Pedal Module for the subject vehicles.
    Condition Requires Extreme Temperatures, Pedal Assembly Warms 
Quickly: The root cause of the condition is an increase in friction 
that may occur on some ETC Accelerator Pedal Modules due to a stack-
up of tolerances, but only when the Module is subjected to extreme 
ambient temperatures. All tests at temperatures above those extremes 
resulted in full compliance with the FMVSS No. 124 time limits for 
all pedal assemblies tested. Therefore, the ambient temperatures 
required for the possibility of the noncompliance to exist are 
severe. Even if a vehicle with a disconnected return spring soaked 
under the necessary harsh conditions for a sufficient time, the 
potential for the noncompliance to occur would exist for only a 
short time, because the pedal assembly would warm up quickly with 
activation of the vehicle heating system.
    Warranty Data: GM has reviewed warranty data for these 2004 
vehicles, as well as complaint data. GM is unaware of any data 
suggesting the subject condition is a real world safety issue.
    Prior NHTSA Decision: On August 3, 1998, NHTSA granted a 
petition for decision of inconsequential noncompliance to GM for 
1997 Chevrolet Corvettes that failed to meet the requirements of 
FMVSS No. 124, with respect to the requirement to return to idle in 
less than 3 seconds at -40 [deg]C.

    Additional information was requested from GM. One of the factors 
considered in the prior petition grant (63 FR 41320, August 3, 1998) 
was that the accelerator control system performance of the Corvettes 
improved after several thousand application cycles of the accelerator 
pedal.
    However, in the present case, GM and its pedal assembly supplier 
conducted several tests of samples from the subject population 
attempting to demonstrate this kind of improvement by cycling pedal 
assemblies at ambient and cold temperatures, but the throttle return 
performance was not significantly improved.
    Six accelerator pedal assemblies were taken from GM vehicles with 
up to 11,553 accumulated driving miles and tested on a fixture with one 
return spring disconnected at -40 [deg]C and higher temperatures. 
Checking times to return from 10 percent, 50 percent, and 100 percent 
wide-open throttle positions to idle, two of the assemblies returned to 
idle within three seconds. The four others had not fully returned 
within one minute.
    The worst performer of these assemblies was installed in a vehicle 
for testing on a dynamometer in a cold chamber. The driver accelerated 
to 70 mph and removed his foot from the accelerator control pedal. 
Vehicle speed reduced slowly. Tapping or pumping the accelerator pedal 
had little affect. Side taps applied to the pedal improved return time 
such that the pedal returned within 40-50 seconds. When the driver used 
his foot to lift up the pedal, the idle condition was achieved within 
five seconds.
    The standard requires that a vehicle's accelerator control system, 
with one return spring disconnected, return to idle in cold ambient 
temperatures within three seconds. A driver who starts a vehicle 
affected by the noncompliance in these conditions and begins driving it 
soon thereafter could be unable to control vehicle speed and experience 
a loss of control.
    In consideration of the foregoing, NHTSA has decided that the 
petitioner has not met its burden of persuasion that the noncompliance 
described is inconsequential to motor vehicle safety. Accordingly, GM's 
petition is denied.

    Authority: 49 U.S.C. 30118, 30120; delegations of authority at 
CFR 1.50 and 501.8.

    Issued on: January 19, 2005.
Claude H. Harris,
Director, Office of Vehicle Safety Compliance.
[FR Doc. 05-1433 Filed 1-25-05; 8:45 am]
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