GF27.60-P-3012AHS Emergency Default Mode, Function

GF27.60-P-3012AHS Emergency default mode, function
- Transmission 722.9


Function requirements for limp-home mode, general
^ Circuit 87 ON
^ Circuit 61 (engine running)

Limp-home mode, general
In order to ensure safe driving and to prevent damage to the transmission, the fully integrated transmission control unit (VGS) (Y3/8n4) switches to limp-home mode in the event of critical faults.

The fault is stored in the fault memory with the assigned fault code and the engine diagnosis indicator lamp (A1e58) in the instrument cluster (A1) is actuated via the central CAN (CAN F).

In addition, the ME-SFI [ME] control unit (N3/10) (with gasoline engines) or the CDI control unit (N3/9) (with diesel engines) are informed of the fault via the drive train CAN (CAN C).

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 be engaged.

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

If hydraulic faults occur, the transmission remains in the gear currently engaged.

In the event of control solenoid valve faults, the respective 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 the Diagnosis Assistance System (DAS).