Code 42, Vehicle Speed Sensor Circuit: Notes

WARNING: This page is about a different car, the 1992 Geo Prizm. However, it is still accessible from the selected car via links, so may be relevant.

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.

NOTE: Test numbers refer to test numbers on diagnostic chart.

If speedometer is inoperative, it could set Code 42.
Checks to see if VSS behind instrument cluster will toggle the 12 volts supplied by ECM.