LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Geo >> 1992 >> Prizm Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Diagnostic Code Charts (GSI) >> Code 42, Vehicle Speed Sensor Circuit >> Notes
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Code 42, Vehicle Speed Sensor Circuit: Notes

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