P0501

DIAGNOSTIC TROUBLE CODE PO5O1
Speed signal (FR) faulty

Fault Symptom.
CHECK ENGINE lamp (MIL) on, poorer AC performance

Condition
Wheel speed below 2 km/h (1.3 mph) while engine under load and engine speed higher than 2600 rpm

Diagnostic Procedure.
1. Connect the ISAT and activate the command "WHEEL SPEED RF" in the "OBTAIN READ- OUTS" menu. Drive the car and compare the speed on the "ISAT" display with the speed shown on the speedometer.

If the speeds coincide, proceed to step 4.
If they do not coincide, continue with the next step.

2. With the ignition switched off, Connect a BOB between the control module and its wiring.
Raise the car, turn the ignition switch to the DRIVE position and rotate the right-hand front wheel. The voltage across pins 9 and 14 should now alternate between 0 V and 10 V.

If the voltage is OK, proceed to step 4.

3. Check the lead between pin 9 of the MOTRONIC control module and pin 7 of the ABS control module for continuity/shorting.

If the lead is OK, check the output signal from pin 7 of the ABS control module. Check ABS fault diagnosis.

4. If no faults have been localized in the above tests, clear the trouble code and drive the car on the road to check whether the code is generated afresh.

If it is, continue at "Before Control Module Replacement" for further diagnostic instructions. Before Replacing A Control Module