Defect Investigation Detail
INTERNATIONAL / PROSTAR / 2013
| Components - Details | |
|---|---|
| NHTSA Action Number: PE15013 | Vehicale/Equipment Name: INTERNATIONAL |
| Vehicale/Equipment Model: PROSTAR | Vehicale/Equipment Year: 2013 |
| Component Name: VEHICLE SPEED CONTROL:ACCELERATOR PEDAL | Manufacturer's Name: Navistar, Inc. |
| Date Opened: Apr, 17 2015 | Date Closed: Dec, 04 2015 |
| Subject: Accelerator Pedal Fails to Return | Summary: The office of defects investigations (odi) opened preliminary evaluation (pe15-013) on 2012-2013 model year (my) navistar prostar vehicles for throttle pedals failing to return to the idle position after being depressed.ewr field reports supplied by navistar describe the non-returning throttle pedals as preventing the engine brake from activating and elevated engine speed making it difficult to stop the vehicle.odi contacted complainants who alleged the accelerator pedal didn’t return to the idle position.some drivers indicated they were annoyed, while others stated that at idle they were able to keep the vehicle stopped but need to apply more pressure to the brake pedal.some consumers indicated that the engine speed was so high with a manual transmission that the engine-brake would not work, while other stated they were able to pull the accelerator pedal back from underneath with their foot and bring the engine speed back to normal.in navistar’s response to an odi information request letter, they made odi aware of 24 consumer complaints concerning non-returning pedals, mostly on manual transmission vehicles.there were no crashes, property damage, injuries or fatalities reported.navistar identified 1,233 warranty clams related to all accelerator pedal issues, with 70.3% of these claims were on manual transmission vehicles.navistar informed odi that they became aware of an unauthorized part change to the throttle control unit assembly (manufactured by williams controls) from april 2012 to march 2013.this unauthorized change was corrected and all vehicles were being retrofitted with the new/original designed part.the design of the subject vehicle throttle pedal is a solid-state rotary position sensor device, which transfers voltage based on shaft rotation in either direction from a reference angle.shaft rotation is obtained by the driver stepping on the accelerator pedal or allowing the pedal to return back to closed throttle (ct) position.navistar has described how the throttle does not return completely to the ct position due to stack up tolerance issues and backlash in the pinion/lever arm gear set.the accelerator pedal sensor stator can move slightly on the mounting bracket if the accelerator pedal is pushed with extra force.on two separate occasions an odi investigator drove several of the subject vehicles.the vehicles that had a high idle with automatic transmissions were reasonable to stop even at the elevated engine speeds.due to the architecture of an automatic transmission, the engine speeds never got high enough to demonstrate a safety related defect while being driven by the odi investigator.however, the manual transmission vehicles showed a propensity to increase engine speeds in excess of 2,300 rpm’s while the vehicle was at rest.this condition occurs when the clutch is depressed the engine can rise to the elevated governed rpm, resulting in difficulty selecting gears while shifting.in the condition of a loaded vehicle going down a long grade, the inability to down shift could cause difficulty in maintaining or reducing vehicle speed with just the service brakes.navistar recognizes the pedal issue as a safety related defect and is preforming safety recall 15v-776.the recall will only address vehicles with the manual transmission.odi believes the manual transmission population exhibits a failure mechanism that represents a safety defect and the automatic supplied transmissions vehicles are drivable without similar consequence.the remedy involves recalibration of the engine electronic control module (ecm) to eliminate the high idle condition caused by pedal housing tooling change.with recall action 15v-776 taken by navistar, this investigation is closed as further use of agency resources does not appear to be warranted. |