Limp-Home Mode, Function

Operation 

In order to ensure a safe driving state and to prevent damage to the automatic transmission, the ECT control module (N15/3) switches to limp-home mode in the event of critical faults. A fault code assigned to the fault is stored in memory.

All solenoid and regulating valves are thus de-energized.

Effect 

• The gear last engaged remains engaged.
• The modulating pressure and shift pressure rise to the maximum levels.
• The torque converter lockup clutch is switched off.

In order to preserve the operability of the vehicle to some extent, the hydraulic control can be used to engage 2nd gear or reverse:

• Stop vehicle.
• Switch off engine.
• Move selector lever to "P".
• Wait at least 10 seconds.
• Start engine.
• Move selector lever to "D": 2nd gear.
• Move selector lever to "R": Reverse gear).

The limp-home function remains active until the fault is rectified or the stored fault code is erased. Sporadic faults can be reset via ignition OFF/ON.

1. Upshift/Downshift Solenoid Valve, Location/Design/Task/Function
   
   See UPSHIFT/DOWNSHIFT SOLENOID VALVE, LOCATION/TASK/DESIGN/FUNCTION  .
2. Location/Task/Design/Function Of PWM Solenoid Valve, Torque Converter Lockup Clutch
   
   See LOCATION/TASK/DESIGN/FUNCTION OF PWM SOLENOID VALVE, TORQUE CONVERTER LOCKUP CLUTCH  .
3. Modulating Pressure Regulating Solenoid Valve, Location/Task/Design/Function
   
   See MODULATING PRESSURE REGULATING SOLENOID VALVE, LOCATION/TASK/DESIGN/FUNCTION  .
4. Shift Pressure Regulating Solenoid Valve, Location/Task/Design/Function
   
   See SHIFT PRESSURE REGULATING SOLENOID VALVE, LOCATION/TASK/DESIGN/FUNCTION  .