Description of DTC code P0503

When the DTC P0503 OBDII code is set, it is because the Powertrain Control Module (PCM) has detected a voltage input signal from the Vehicle Speed Sensor (VSS), which is erratic or intermittent.

The PCM monitors the vehicle speed using data from one or more speed sensors. It compares the VSS sensor inputs with the Anti-lock Braking System (ABS) inputs.

If the PCM detects an intermittent input voltage signal from the primary VSS Sensor, this code will be stored and the malfunction light will illuminate.

Symptoms of fault code P0503

  • Check Engine light ON.
  • The speedometer functionality is erratic.
  • Irregular patterns of transmission changes.
  • The ABS may not operate properly.

Causes of OBD2 P0503

Reasons for setting the P0503 OBD2 fault code:

  • Excessive metallic debris may be present in the speed sensors.
  • The Vehicle Speed Sensor may be faulty.
  • The reluctor ring may have had wear.
  • The wiring harness is likely disconnected or in poor condition.

Possible solutions of the DTC code P0503

To solve failures related to the P0503 OBDII error code, try this:

  • Consult the specific Technical Service Bulletins for your vehicle model.
  • Check all the system wiring. Also, check the Speed Sensors as well as their connectors. Check the circuits for shorted or open circuits. Repair as necessary.
  • Check with a DVOM the resistance of the VSS sensor. Compare with the manufacturer's recommendations, if they do not match, you should replace the sensor.

Codes related to P0503

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