DTC P0503: Vehicle Speed Sensor (VSS) Intermittent

WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2005 Mercury Sable, 2005 Mercury Mountaineer, 2005 Mercury Monterey, 2005 Mercury Montego, and 2005 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.

P0503 - VEHICLE SPEED SENSOR (VSS) INTERMITTENT

Description:	Indicates poor or noisy VSS performance. Vehicle speed data is received from either the VSS, the transfer case speed sensor (TCSS), or the anti-lock brake system (ABS) control module.
Possible Causes:	Noisy VSS/TCSS input signal from the radio frequency interference / electro-magnetic interference (RFI/EMI) external sources, such as ignition components or the charging circuit Damaged VSS or driven gears Damaged TCSS Damaged wiring harness or connectors Malfunction in the module(s) or circuit connected to the VSS/TCSS circuit After market 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
Excursion, F-Super Duty	GO to DF: Vehicle Speed Circuit (VSC) Check STEP DF1.
Five Hundred, Freestyle, Montego, Navigator	The powertrain control module (PCM) uses information from the anti-lock brake system (ABS) module and the transmission control module (TCM) to calculate vehicle speed. Check these modules for DTCs.
Vehicles with a manual transfer case	GO to DP: Vehicle Speed Sensor (VSS)/Transfer Case Speed Sensor (TCSS) STEP DP15.
Vehicles with an automatic transmission and output shaft speed (OSS) sensor DTCs	Refer to AUTOMATIC TRANSMISSION .
All others	GO to DP: Vehicle Speed Sensor (VSS)/Transfer Case Speed Sensor (TCSS) STEP DP12.