Code 42 (PRIZM) - Vehicle Speed Sensor Circuit, Open Or Shorted Circuit: Notes

Vehicle Speed Sensor (VSS) is an electronic relay mounted on transaxle. As transaxle rotates VSS, VSS provides speedometer with a vehicle speed input (voltage pulses). This signal drives speedometer. Speedometer converts vehicle speed input into a more precise waveform and provides ECM, and cruise control module with a vehicle speed input. ECM converts this input (ground pulses) into vehicle speed. Code 42 will set if vehicle speed input is not sensed at ECM with engine speed 3000-5000 RPM and transaxle in gear, for at least 8 seconds.

1. Determines if VSS is functioning properly.
2. Checks for open in power feed to VSS.
3. Checks for open or short in ECM speed input circuit or a faulty ECM.
4. Determines if ECM or speedometer is faulty.
5. Checks for open in ground to VSS.
6. Checks for open in power feed to speedometer.
7. Determines if VSS or speedometer is faulty.