Diesel Data: Automotive Repair

DR-8B Speed Sensor Circuit


1. Disconnect speed sensor connector, then connect positive lead of a voltmeter to white/orange wire of speed sensor harness connector.
2. Connect negative lead of a voltmeter to black/blue wire of speed sensor harness connector.
3. Turn ignition switch to Run position.
4. If voltmeter reads within 3 1/2 volts, inspect transaxle drive gear to speed sensor drive gear for proper contact.
5. If voltmeter reads zero volts move negative lead to ground, repair ground wire for open circuit.
6. If voltmeter still reads zero volts, proceed to Step C.