P0500

VEHICLE SPEED SIGNAL





Symptom Of Fault.
SHIFT UP lamp out of order (cars with a manual gearbox).
Fuel shut-of in all gears.
Low boost pressure in 2nd, 3rd, 4th and 5th gears, manual gearbox.
ABS warning lamp may be on.

Conditions.
P0500: All-embracing DTC.
P0501: ignition switch in ON position.
vehicle speed > 168 mph (> 270 km/h).
P0502: brake pedal not depressed.
engine speed > 1800 rpm
intake manifold pressure > 60 kPa
no vehicle speed signal for 4 seconds.
Above conditions fulfilled and then no vehicle speed signal for 17 minutes.

Diagnostic Help.
A vehicle speed signal reading can be obtained on the ISAT scan tool.
- Select "READ FUNCTIONS".
- Select "CAR SPEED".
The ISAT scan tool should show the current wheel speed.
Drive the car and compare the ISAT scan tool reading with the speed indicated on the speedometer.





Diagnostic Procedure.
1. Check the speedometer
- Drive the car and check that the speedometer indicates a plausible speed.

Does the speedometer indicate a plausible speed?
YES:
^ Continue with point 2.
NO:
^ Continue fault diagnosis in the Electrical System.





2. Check the wheel speed signal
- Jack up a front wheel and put the gear lever in position N.
- Unplug the control module's 70-pin connector.
- Ignition switch in ON position.
- Connect the test lamp to pins 39 and 1 of the female connector.
- Rotate the wheel.

Does the test lamp flash?
YES:
^ Continue with point 3.
NO:
^ Check the lead between pin 2 of the speedometer and pin 39 of the Trionic control module for continuity and shorting. If necessary, repair or replace the lead.
If the lead is OK, continue fault diagnosis in the Electrical System.





3. Final check:
- Clear the diagnostic trouble code.
- Implementation of driving cycle: Drive the car at varying engine rpm and loads for 5 minutes.
- Evaluation of driving cycle:
- Connect an ISAT scan tool.
- Select "READ FUNCTIONS".
- Select "CAR SPEED".
- Check that the ISAT scan tool shows the same speed as the speedometer.

Is the ISAT scan tool reading incorrect?
YES:
^ Continue fault in the A/C System.
NO:
^ The remedial measure taken was correct