Equipped With ABS

P0503-VEHICLE SPEED SENSOR 1 ERRATIC (Equipped with ABS)






For a complete wiring diagram refer to: Electrical Diagrams

When Monitored
Ignition on and battery voltage greater than 10 volts. Transmission in Drive or Reverse.

Set Condition
Vehicle speed signal is erratic during road load conditions. One Trip Fault. Three good trips to turn off the MIL.

Possible Causes
- ACTIVE BUS OR COMMUNICATION DTCS
- TIRE CIRCUMFERENCE
- PCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test
1. ACTIVE DTC





NOTE: The following items must be check before continuing.
^ Pinion Factor and Tire Size MUST be programmed in the ABS Module.
^ All Bus Communication DTCs MUST be diagnosed.
^ All related Vehicle Speed and Wheel Speed DTCs that may be active in the ABS Module MUST be diagnosed. Refer to the ABS diagnostic information for the correct procedure.

Ignition on, engine not running.
With a scan tool, read DTCs.

Is the DTC active at this time?
Yes >> Go To 2
No >> Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
2. VISUAL INSPECTION

NOTE: This code can set due following conditions.
^ Unequal tire circumference between the tires on the vehicle.
^ Front or Rear wheels moving while the opposite wheels are not. (i.e., wheels slipping on loose gravel, ice or hard acceleration)

Check tire pressure of all the tires.
Check tire wear on all the tires.
Ask the customer what the road and driving conditions were like when the fault set.

Were any of the above conditions found?
Yes >> Repair as necessary If the code set during a front OR rear wheel spin condition, no repair is necessary.
Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No >> Go To 3
3. PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Were there any problems found?
Yes >> Repair as necessary
Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No >> Replace and program the Powertrain Control Module per Service Information.
Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test