GF27.60-P-3012AHV Limp-Home Mode, Function

GF27.60-P-3012AHV Limp-home Mode, Function
- TRANSMISSION 722.930 in MODEL 204.0 /2 /3

Function requirements for limp-home mode, general

^ Circuit 87 (connected circuit 15) ON
^ Circuit 61 (engine running)

Limp-home mode, general

In order to guarantee a safe driving condition and to avoid damage to the transmission, the fully integrated transmission control unit (Y3/8n4) switches to limp-home mode in the event of critical faults.

The fault is stored with the assigned fault code in the fault memory and the ME-SFI [ME] control unit (N3/10) over the drive train CAN (CAN C).

The ME-SFI [ME] control unit routes the fault signal over the chassis CAN (CAN E) to the instrument cluster (A1), which then activates the engine diagnosis indicator lamp (A1e58).

In the event of a hardware fault, all control solenoid valves are switched off and the transmission switches to 6th gear.

After gear range "P" is engaged, gear range "R and D" can also be engaged.

In gear range "D", the transmission shifts to 2nd gear.

If hydraulic faults occur, the transmission remains in the respective gear.

In the event of control solenoid valve faults, the affected gear is disabled and no longer actuated.

As a result the vehicle can be brought to the nearest Mercedes-Benz service operation.

Diagnosis

Up to 16 faults can be stored simultaneously in the fault memory. These can be read out using Xentry diagnostics.