DTC P0503: Vehicle Speed Sensor (VSS) A Intermittent/Erratic/High

P0503 - VEHICLE SPEED SENSOR (VSS) A INTERMITTENT/ERRATIC/HIGH

Description: Indicates incorrect or noisy VSS performance. Vehicle speed data is received from either the VSS or the anti-lock brake system (ABS) control module.
Possible Causes : Noisy VSS input signal from radio frequency interference or electromagnetic interference external sources, such as ignition components or the charging circuit Damaged VSS or driven gears Damaged wiring harness or connectors Concern in the modules or circuits connected to the VSS circuit Aftermarket add-on
Diagnostic Aids: Monitor the VSS PID while driving the vehicle, and check for intermittent vehicle speed indication. Verify the ignition and charging systems are functioning correctly.
Application	Key On Engine Off	Key On Engine Running	Continuous Memory
F-Series Super Duty, Motorhome / Stripped Chassis / Step Van	GO to PINPOINT TEST DF .
Manual Transmission	GO to PINPOINT TEST DP .
All others	The PCM uses information from the ABS control module and the transmission control module (TCM) to calculate vehicle speed. Check these modules for DTCs.