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

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

Description: This DTC sets when an incorrect or noisy VSS signal is detected. Vehicle speed data is received from either the VSS or the anti-lock brake system (ABS) 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 VSS 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-650/F-750, F-Series Super Duty, Fiesta, Fusion, Motorhome/Stripped Chassis/Step Van	GO to PINPOINT TEST DF: VEHICLE SPEED CIRCUIT (VSC) CHECK .
Manual Transmission	GO to PINPOINT TEST DP: OUTPUT SHAFT SPEED (OSS) SENSOR/VEHICLE SPEED SENSOR (VSS) .
All others	The PCM uses information from the ABS module and the transmission control module (TCM) to calculate vehicle speed. Check these modules for DTCs.