Prizm L4-1800cc 1.8L DOHC (1993)
Vehicle Speed Sensor Circuit
Failure Mode
DTC 42 will set if the following condition is met for at least 8 seconds:
Vehicle speed input not sensed at the PCM with engine speed between between 3,00O and 5,000 rpm with the transaxle in gear.
Test Description:
Numbers below refer to circled numbers on the diagnostic chart.
1. This determines if the VSS is functioning normally.
2. This checks for an open in the power feed to the VSS.
3. This checks for an open or short in the PCM speed input circuit or for a faulty PCM.
4. This determines if the PCM or the speedometer is faulty.
5. This checks for an open in the ground to the VSS.
6. This checks for an open in the power feed to the speedometer.
7. This determines if the VSS or speedometer is faulty.
