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

GF27.60-P-3012AHC Emergency default mode, function
- Transmission 722.902/904/906/908


Function requirements
^ Circuit 87 ON
^ Circuit 61 ON

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 in the fault memory with the assigned fault code and the engine diagnosis indicator lamp (A1e58) in the instrument cluster (A1) is actuated.

In addition the fault can be communicated to the CDI control unit (N3/9) (with diesel engines) or ME-SFI control unit (N3/10) (with gasoline engines) 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 engaging gear range "P" it is possible to engage gear range "R" or "D".

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 affected gear is disabled and no longer actuated.

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

Up to 16 faults can be stored simultaneously in the fault memory. These can be read out using the Diagnosis Assistance System (DAS).