GF27.60-P-3012AHX Limp-Home Mode, Function

GF27.60-P-3012AHX Limp-Home Mode, Function
TRANSMISSION 722.930 up to 31.5.11, 722.931 as of 1.6.11
in MODEL 212.0/ 2

Function requirements for limp-home mode, general
^ Status "Circuit 87 ON"
^ Circuit 61 ON

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. The fault is also sent to the ME-SFI [ME] control unit (N3/10) via the chassis CAN (CAN E).

In the event of a hardware fault, the following control solenoid valves are switched off and the transmission shifts to 6th gear.
- Working pressure control solenoid valve (Y3/8y1)
- Clutch control solenoid valve K1 (Y3/8y2)
- Clutch control solenoid valve K2 (Y3/8y3)
- Clutch control solenoid valve K3 (Y3/8y4)
- Multidisk brake control solenoid valve B1 (Y3/8y5)
- Multidisk brake control solenoid valve B2 (Y3/8y6)
- Multidisk brake control solenoid valve B3 (Y3/8y7)
- Wet clutch control solenoid valve (Y3/8y9)

After selector lever position "P" has been activated, it is possible to engage selector lever position "R" or "D".
In selector lever position "D", the transmission shifts to 2nd gear.
If hydraulic faults occur, the transmission remains in the respective gear.
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 Xentry diagnostics.