Main Instrument Unit

Vehicle Speed Signal Faulty:

Fault symptoms
Speedometer in max. position, 250 km/h.

Condition
Speed information from ABS exceeds 270 km/h.

Diagnostic help
A reading of the current speed can be obtained with the diagnostic tool.
The speedometer can also be activated with the diagnostic tool.
When the speedometer is activated with the diagnostic tool, the reading obtained will not go out on the bus.

Check the wiring harness
Jiggle the wiring harness at several points and in different directions to detect intermittent breaks and short-circuits in the leads. Observe the multimeter, test lamp or diagnostic tool during the test.