Limp-home mode, function - GF27.60-P-3012AHW

WARNING: This page is about a different car, the 2011 Mercedes-Benz C300, 2010 Mercedes-Benz C300, 2009 Mercedes-Benz C300, and 2008 Mercedes-Benz C300. However, it is still accessible from the selected car via links, so may be relevant.

TRANSMISSION 722.9 (except 722.930) in MODEL 204.0 as of model year 2009/YoM 08

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 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 is communicated to the CDI control unit (N3/9) or ME-SFI control unit (N3/10) 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.

It is possible to engage gear range "R, D" after engaging gear range "P".

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.

Diagnosis

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