Fault Conditions

P0501

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 50-205 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 s has expired since start. Vehicle speed has exceeded 0 on some occasion.

Fault handling: (For more information, Fault Handling III, Other Emission-Related Components and Function)

^ Type III.

Diagnostic help
Fault diagnosis concerns electrical faults in connecting cables to ABS (check first whether there is a fault in ABS or TC/ABS). Communication with Trionic is via the P-bus if the car is equipped with TC/ABS. For further information on fault diagnosis of bus communication with TC/ABS, see Fault diagnosis strategy for electronic systems. DTC P1625 will be generated if TC/ABS is missing from the bus, see P1625.
Diagnostic Strategies
P1625

Functions in the diagnostic tool related to the fault:
^ Diagnostic status for the diagnosis.
^ Vehicle speed (Lead from ABS, alternatively bus from TC/ABS), unit km/h.

For more information refer to description of read values, Menu Read Values

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.