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

Transmission 722.9 in model 463 as of model year 2013 

Function requirements, general 

• Engine running

The CDI control unit (N3/9) (diesel engine) or the ME-SFI control unit (N3/10) (gasoline engine) sends the "engine running" signal via the drivetrain CAN (CAN C) to the fully integrated transmission control unit (Y3/8n4).

Function sequence for limp-home mode 

In order to ensure safe driving and to prevent damage to the transmission, the fully integrated transmission control unit switches to limp-home mode in the event of critical faults. The fault is stored with the assigned fault code in the fault memory.

The fully integrated transmission control unit sends the fault signal via the drivetrain CAN, CDI control unit (engine 642) or ME-SFI control unit (engine 157, 273) or powertrain control unit (N127) (engine 176), chassis CAN 1 (CAN E1), electronic ignition lock control unit (N73) and chassis CAN 2 (CAN E2) to the instrument cluster (A1), which switches on the engine diagnosis indicator lamp (A1e58).

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 ranges "R" and "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.

Up to 16 faults can be stored simultaneously in the fault memory.

	Electrical function schematic, fully integrated transmission control		PE27.19-P-2061-97ZGA
	Overview of system components for automatic transmission (AT)		GF27.10-P-9992AHG