Conditions

Vehicle Speed. Input Signal Outside Limits.





Fault symptoms
- CHECK ENGINE.
- Cruise control inoperative.
- 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 - 205 km/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:
- Cruise control is blocked. Vehicle speed (Bus from MIU) is used as a substitute value. The idling adaptation is blocked and reset.

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

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

Diagnostic help
Fault diagnosis concerns electrical faults in connected leads to ABS (First it is checked if there are faults in the ABS or TC/ABS). If the car is equipped with TC/ABS the communication to the Trionic occurs through the P-bus. For further information about fault diagnosis of the communication with TC/ABS, see Brakes and Traction Control/Description and Operation/TC/ABS 5.3. If TC/ABS is not present on the bus, diagnostic trouble code P1925 is generated, see P1925.
P1925

Diagnostic tool functions related to this fault are:
- Diagnostic status for the diagnosis.
- Vehicle speed (Lead from ABS, alternatively bus from TC/ABS.), unit km/h.

See also the description of test values under "Fault diagnosis, general" for more information.
Tech 2 Menu Structure, DTC Menu, Read Value, Activate, Sys Info

Check the wiring
Jiggle the leads and in-line connectors at various points and in different directions to detect any intermittent breaks or short circuits in the wiring. Observe the multimeter, test lamp or diagnostic tool while doing this.

Proceed to Diagnostic Procedures Checking Diagnostic Trouble Codes In the ABS