Denial of Motor Vehicle Defect Petition

AGENCY:

National Highway Traffic Safety Administration (NHTSA), Department of Transportation.

ACTION:

Denial of petition for a defect investigation.

SUMMARY:

This notice sets forth the reasons for the denial of a petition submitted to NHTSA under 49 U.S.C. 30162, by Mr. William Salyer, requesting that the agency commence a proceeding to determine the existence of a defect related to motor vehicle safety in certain Jeep Cherokee and Jeep Grand Cherokee vehicles. After a review of the petition and other information, NHTSA has concluded that further expenditure of the agency's investigative resources on the issues raised by the petition does not appear warranted. The agency accordingly has denied the petition. The petition is hereinafter identified as DP02-005.

FOR FURTHER INFORMATION CONTACT:

Mr. Jonathan White, Chief, Defect and Recall Information Analysis Division, Office of Defects Investigation (ODI), NHTSA, 400 Seventh Street, SW., Washington, DC 20590. Telephone: (202) 366-5226.

SUPPLEMENTARY INFORMATION:

On April 11, 2002, Mr. Walter Salyer submitted a petition requesting that the agency investigate sudden acceleration in model year (MY) 1991-1995 Jeep Cherokee and MY 1993-1995 Jeep Grand Cherokee vehicles (subject vehicles), a vehicle population of 1,302,000. The petition alleges that a defect exists in the subject vehicles involving the design and assembly of the connector interface between the main wiring harness and the powertrain control module (PCM) in these vehicles. The petitioner states that with the cruise control power switch in the “OFF” position, the potential at the vent and vacuum pins is approximately zero volts. The neighboring pins are all operating at approximately battery voltage. Mr. Sayler alleges that current flow from the neighboring pins to the vent and vacuum pins could occur in the presence of an electrically conductive contaminant (water/moisture), and that energization of the cruise control can occur. Mr. Salyer alleges that such cruise control energization leads to a rapid increase in engine speed to wide-open throttle. Mr. Salyer further alleges that depending on the state of the cruise control power switch, this undesired acceleration may, or may not, be terminated by application of the service brakes.

The cruise control system in the subject vehicles is electrically controlled and vacuum operated. The PCM operates the vehicle speed control system by controlling the vent and vacuum functions of the speed control servo circuits. Depending on the signal it receives from the vehicle speed control switches, the PCM either applies vacuum to or vents vacuum from the servo, by applying voltage to either the vent or vacuum pin. The servo is directly connected by cable to the throttle plate in the throttle body.

The petitioner, Mr. Salyer, correctly states that with the cruise control power switch in the “OFF” position, the potential at the vent and vacuum pins is zero volts. The neighboring pins are operating at approximately battery voltage. Mr. Sayler concludes that current flow from the neighboring pins to the vent and vacuum pins could occur in the presence of an electrically conductive contaminant (water/moisture), and that energization of the cruise control can occur. An analysis of the cruise control circuit shows that it maybe possible for the engine to operate at full throttle if this malfunction occurs. The cruise control is designed to be deactivated with brake pedal application; however, Mr. Salyer notes that if other parts of the system malfunction at the same time, it is possible that the cruise control will not shut off.

In September 1997, DaimlerChrysler Corporation (DCX) commenced a Safety Improvement Campaign, 97I-002, to install brake transmission shift interlocks (BTSI) in MY 1984-1995 Jeep Cherokees and Wagoneers and MY 1993-1995 Jeep Grand Cherokee and Grand Wagoneer vehicles equipped with automatic transmissions, a total of 1,010,000 vehicles. The BTSI prevents the operator from shifting out of “Park” unless the brake pedal is depressed.

In March 1998, Mr. Salyer's company, Infospace, Inc., conducted an analysis of a sudden acceleration crash occurring in June 1996 involving a MY 1993 Jeep Grand Cherokee in Mercer Island, Washington. This vehicle did not have a BTSI. The Grand Cherokee allegedly suddenly accelerated when the operator shifted into “Drive” and hit a retaining wall, resulting in a serious injury to a pedestrian. Mr. Salyer's analysis concluded that water in the PCM was the cause of the sudden acceleration.

The number of sudden acceleration reports involving the subject vehicles received by ODI from consumers in each calendar year from 1993 through June 12, 2002, shows a marked reduction in reports in 1998 and continuing through June 2002. In addition, the data furnished by Mr. Salyer also shows a dramatic downward trend since 1997. This data obtained solely from DCX is illustrated on page 36 of the petitioner's report, and shows approximately 210 reports in 1997 and 30 in 2000. It appears that DCX's safety improvement campaign has had a dramatic effect, implying that the major cause for the sudden acceleration in the subject vehicles was incorrect pedal application.

ODI has received a total of 476 complaints of sudden, unintended acceleration, for all causes, on the subject vehicles. Only 36 complaints of sudden acceleration, for all causes, have been reported during the past two years. None of these complaints refer to any malfunction or defect related to the main wiring harness connector or the PCM and none refer to water intrusion into the PCM.

While it may be possible for water in the PCM to activate the cruise control in the subject vehicles under rare circumstances, such activation would not lead to a sudden acceleration incident unless there was also a malfunction of the switch that shuts off the cruise control upon application of the brake pedal. Moreover, incidents of sudden acceleration in the subject vehicles have significantly decreased since the beginning of DCX's campaign, so that the current rate of such incidents is comparable to the rates of other vehicle models. Thus, it appears that the predominant cause of sudden acceleration incidents involving the subject vehicles has been pedal misapplication, rather than water contamination.

For the foregoing reasons, further expenditure of the agency's investigative resources on the issues raised by the petition does not appear to be warranted. Therefore, the petition is denied.

Authority: 49 U.S.C. 30162(d); delegations of authority at CFR 1.50 and 501.8.