Limp-Home Mode

In order to ensure safe driving and to prevent further damage to the automatic transmission, the Transmission Control Module switches to limp-home mode in the event of a critical failure. A diagnostic trouble code assigned to the failure is stored in memory. All solenoid and regulating valves are thus de-energized. The result is that the gear last engaged remains engaged, the modulating pressure and shift pressure rise to the maximum levels, and the torque converter lockup clutch is disarmed. In order to preserve the operability of the vehicle to some extent, the automatic transmission internal hydraulic control can be used to engage second gear or reverse by: stopping the vehicle, switching off the engine, moving the shift selector lever to Park, waiting at least ten seconds, starting the engine, and moving the shift selector lever to drive to access second gear, or moving the shift selector lever to Reverse if needed. The limp-home function remains active until the failure is corrected or the stored diagnostic trouble code is erased. Sporadic failures may also be reset by switching the ignition switch from Off to On.