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

GF27.60-P-3012LEH Emergency default mode, function
- TRANSMISSION 722.950

Function requirements for limp-home mode, general
^ Circuit 87 (connected circuit 15) ON
^ Circuit 61 (engine running)

Limp-home mode, general
In order to ensure safe driving and to prevent damage to the transmission, the fully integrated transmission control unit (VGS) (Y3/8n4) switches to limp-home mode in the event of critical faults.

The malfunction is filed along with the assigned fault code in the fault memory and the engine diagnosis indicator lamp (A1e58) in the instrument cluster (A1) is actuated over the central CAN (CAN F). The malfunction is also notified to the ME-SFI [ME] control unit (N3/10) over 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" using the DIRECT SELECT gear selector switch (S16/13) the gear ranges "R" and "D" can then be engaged.

In gear range "D", the transmission shifts to 2nd gear. If hydraulic faults occur, the transmission remains in the gear currently engaged.

With control solenoid valve faults the gears are blocked or no longer actuated for which the affected control solenoid valve is required.

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).