Code 42, Vehicle Speed Sensor Circuit

ECM provides a 12-volt signal to the Vehicle Speed Sensor (VSS). The VSS will toggle the signal low and high, indicating vehicle is moving. Code 42 will set if signal line remains high or low for 4 seconds or more.

1. If speedometer is inoperative, it could be the cause of Code 42.
2. ECM supplies 12 volts to the VSS.
3. The VSS, located on back of instrument panel, will toggle 12 volts supplied by ECM.