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.” GM has filed an appropriate report pursuant to 49 CFR part 573, “Defect and Noncompliance Reports.”
Pursuant to 49 U.S.C. 30118(d) and 30120(h), GM has petitioned for an exemption from the notification and remedy requirements of 49 U.S.C. chapter 301 on the basis that this noncompliance is inconsequential to motor vehicle safety.
This notice of receipt of GM's petition is published under 49 U.S.C. 30118 and 30120 and does not represent any agency decision or other exercise of judgment concerning the merits of the petition.
Approximately 19,924 model year 2004 Cadillac SRX, Cadillac XLR, and Pontiac Grand Prix vehicles are affected. S5.1 of FMVSS No. 124 requires that:
There shall be at least two sources of energy capable of returning the throttle to the idle position within the time limit specified by S5.3 . . . . In the event of failure of one source of energy by a single severance or disconnection, the throttle shall return to the idle position within the time limits specified by S5.3 . . . .
In the event of failure of either of the two Electronic Throttle Control (ETC) Pedal return springs, at ambient temperatures of −30°C to −40°C for the Grand Prix and XLR and −10°C to −40°C for the SXR, the engine in some of the subject 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°C to −40°C for the Grand Prix and XLR and −10°C to −40°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°C.
Interested persons are invited to submit written data, views, and arguments on the petition described above. Comments must refer to the docket and notice number cited at the beginning of this notice and be submitted by any of the following methods. Mail: Docket Management Facility, U.S. Department of Transportation, Nassif Building, Room PL-401, 400 Seventh Street, SW., Washington, DC 20590-0001. Hand delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC. It is requested, but not required, that two copies of the comments be provided. The Docket Section is open on weekdays from 10 a.m. to 5 p.m. except Federal holidays. Comments may be submitted electronically by logging onto the Docket Management System Web site at http://dms.dot.gov. Click on Start Printed Page 28978“Help” to obtain instructions for filing the document electronically. Comments may be faxed to 1-202-493-2251, or may be submitted to the Federal eRulemaking Portal: go to http://www.regulations.gov. Follow the online instructions for submitting comments.
The petition, supporting materials, and all comments received before the close of business on the closing date indicated below will be filed and will be considered. All comments and supporting materials received after the closing date will also be filed and will be considered to the extent possible. When the petition is granted or denied, notice of the decision will be published in the Federal Register pursuant to the authority indicated below.
Comment closing date: June 18, 2004.Start Signature
Issued on: May 14, 2004.
Kenneth N. Weinstein,
Associate Administrator for Enforcement.
[FR Doc. 04-11307 Filed 5-18-04; 8:45 am]
BILLING CODE 4910-59-P