Scan Tool Testing and Procedures

SCAN TOOL TESTING
A scan tool MPH display should closely match the speedometer reading with drive wheels turning. A fault in the Vehicle Speed Sensor (VSS) circuit will set a DTC P0502. If the vehicle speed is suddenly lost while cruising, the PCM will set a DTC P0503 and the transmission will default to keep the transmission from suddenly going into first gear Refer to Automatic Transmission/Transaxle if a problem exists without a DTC P0502. Testing and Inspection