Fault Conditions

Vehicle Speed. Input signal outside limits.







Fault symptoms
- CHECK ENGINE.
- Cruise control not working.
- Low engine torque on cars with manual gearbox.

On-Board Diagnostics
Type of diagnosis:
- Tests 1 and 2: Continuous. But interrupted when fault criteria fulfilled and does not restart until next driving cycle.

Enable criteria:
- Test 1: Engine running.
- Test 2: Engine running. Speed 50-205km/h for longer than 10 s. Brake pedal not depressed.

Fault criteria:
- Test 1: Speed exceeding 270 km/h.
- Test 2: Speed rises more than 120 km/h or drops more than 50 km/h within 1 s.

Dependents:
- None.

System reaction to a fault:
- The cruise control is blocked. Vehicle speed (Bus from MIU.) is used as a substitute value. The idling speed adaptation blocked and reset.

OK report:
- 60 s has expired since start. Vehicle speed has exceeded 0 on some occasion.

Fault handling: Fault Handling III, Other Emission-Related Component & Function
- Type III.

Diagnostic help
Fault diagnosis concerns an electrical fault in connecting leads. (Check if fault is in ABS first.)
Functions in the diagnostic tool related to the fault:
Diagnostic status for the diagnosis.
- Vehicle Speed (Wire from ABS), unit km/h.

For information, Tech 2 Menu Structure, DTC Menu, Read Value, Activate, Sys Info

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

Proceed to Diagnostic Procedures Checking Diagnostic Trouble Codes In the ABS