Mercedes-Benz W164 7G-Tronic limp mode and conductor plate
Why does my W164 gearbox go into limp mode with only one gear working?
Often the cause is the gearbox conductor plate or its speed sensor, so the control unit does not get reliable speed data. Switching the car off resets the mode for a moment, but the fault comes back. First check the ABS wheel speed sensors, because their data is compared with the gearbox speed.
What do W164 7G-Tronic fault codes 2768, 2767 and 0894 mean?
Codes 2767 and 2768 relate to the gearbox internal speed sensor. Code 0894 means the gear is not plausible or is slipping. Code 2232 is an engine message about a fault in the gearbox control unit. The codes only point in a direction and do not identify the fault on their own.
Does the W164 gearbox have to be removed to replace or repair the conductor plate?
The conductor plate can be reached from underneath without removing the gearbox, once the valve body is taken out first. Repairing the conductor plate is usually a cheaper option than a new one and does not require programming. Have the work done at a workshop that knows the 7G-Tronic.
Can a W164 gearbox fault be diagnosed without taking it apart?
Not always. Check the electrical side, sensors and oils first. If the fault is not found there, it is often only revealed by opening the gearbox, and the conductor plate and valve body are typical replacement items.