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

GF27.60-P-3012ACM Emergency default mode, function
- TRANSMISSION 722.643/649
- refinement package
- as of model year 09


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

Limp-home mode, general
In order to guarantee a safe driving condition and prevent damage to the transmission, the electronic transmission control control unit (N15/3) switches to limp-home during critical faults. In the process a fault code assigned to a fault is stored in the fault memory and the engine diagnosis indicator lamp (A1e58) (except code 494 USA version) or the CHECK ENGINE engine indicator lamp (A1e26) (with code 494 USA version) lights up in the instrument cluster (A1).

All solenoid valves and control solenoid valves are in the deenergized condition.

The modulating pressure and shift pressure rise to the maximum value, the torque converter lockup clutch is switched 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 with the DAS.