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

GF27.60-P-3012ACS Emergency default mode, function
- Transmission 722.649


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 automatic transmission, the ETC [EGS] control unit (N15/3) 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).

All solenoid and regulating valves are de-energized.

The modulating pressure and shift pressure increase to the maximum value, the torque converter lockup clutch is shut off. The gear last engaged remains engaged.

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

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

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

Diagnosis

The faults stored in the fault memory can be read out using the Diagnosis Assistance System (DAS).