DTC: P0501/P0502 VSS Circuit: Notes

Vehicle Speed Sensor (VSS) in transaxle provides vehicle speed information to PCM. Voltage level and number of pulses increase with vehicle speed. PCM converts pulsing voltage to MPH, and MPH can be displayed using a scan tester.

Function of VSS buffer, used in past models, has been incorporated into PCM. PCM supplies necessary signal for instrument cluster (4004 pulses per mile) for operating speedometer and odometer.

Code P0501 will set when the following conditions are present.

• Engine is running.
• Code P0703 is not set.
• Transmission is out of Park or Neutral for more than 4 seconds.
• Vehicle speed is greater than 18 MPH.
• Brake is not applied.
• All conditions are met for 2 seconds.

Code P0502 will set when the following conditions are present.

• Vehicle speed goes from less than 3 to zero MPH in less than 2 seconds, brake not applied.
• Engine is running.
• Engine speed is greater than 3000 RPM.
• Transmission is out of Park or Neutral for more than 4 seconds.
  NOTE: Test numbers refer to numbers on diagnostic chart.

1. VSS signal generator only produces a signal if drive wheels are turning greater than 3 MPH.
2. Check PROM for correct application before replacing PCM.