Troubleshooting Charts

Troubleshooting Vehicle speed signal
The vehicle speed signal transmitted from the Speedometer Vehicle Speed Sensor (VSS) (G 22) is processed by the speedometer (G 21) then transmitted to the following systems:

- Cruise control
- Engine management
- Shift lock (automatic transmission)
- Differential lock control system
- Automatic Transmission
- Air conditioner
- Board computer

The board computer and the Auto-check system are internally connected to the vehicle speed signal in the instrument cluster. All other systems dependent on the vehicle speed signal are connected in parallel to the VSS (G 22) and the board computer.
If a short circuit exists, for example in the Cruise Control, Control Module (J213), the vehicle speed signal from the speedometer (G 21) will not be transmitted.
As a consequence, all remaining systems such as the idle control, board computer, etc., will not function properly.
A safety circuit in the speedometer (G21) ensures that the speedometer continues to work.
The speed signal cannot be measured with normal workshop equipment, therefore, troubleshoot as follows:

NOTE: Disregard any procedures referring to components that are not installed in the vehicle.

Starting Test Chart:

Start test here

Test Chart A:

Test A

Test Chart B:

Test B

Test Chart C:

Test C