DTC 3-1-1

3-1-1 VEHICLE SPEED SENSOR SIGNAL




Trouble Code Conditions
If engine speed exceeds 3390 rpm, load signal exceeds 5 ms, and a signal is absent for 3 seconds, Diagnostic Trouble Code (DTC) 3-1-1 is set.

Substitute value(s)
- None.

Fault source(s)
- Signal lead short circuited to live.
- Signal lead short circuited to ground.
- Break in signal lead.
- Contact resistance in connectors.
- Defective speedometer.
- Fault in sensor circuit.

Fault symptom(s)
- None.

TEST PROCEDURE




CHECK SPEEDOMETER SIGNAL TO ENGINE CONTROL MODULE (ECM)
- Test-drive vehicle.
- Enter DTC parameter list.
- Read off speedometer signal.

If speedometer signal OK:
^ Intermittent fault. Proceed to INTERMITTENT FAULT section below.

If Vehicle Speed Sensor (VSS) signal is 0 km/h:
^ Permanent fault. Proceed to PERMANENT FAULT section below.

PERMANENT FAULT
Check speedometer
- Test-drive vehicle.

If speedometer OK:
^ Check VSS signal. Proceed to CHECK VSS SIGNAL section below.

If speedometer reads 0 km/h:
^ Fault trace combined instrument and VSS sensor circuit.




CHECK VSS SIGNAL
- Connect breakout box and check control points.
- Connect ECM.
- Gear selector: neutral.
- Lift vehicle so that rear wheels are clear of ground.
- Ignition on.



- Connect a voltmeter between # 9 and # 19 on breakout box.
- Spin rear wheels.

Voltmeter should read approx. 6 volts.

If value OK:
^ Source of DTC is bad contact in ECM connector.
^ Check connector for contact resistance and oxidation.

If voltmeter reads battery voltage minus approx. 2 volts:
^ Check contact. Proceed to CHECK CONNECTOR section below.

If voltmeter reads battery voltage:
^ Check lead between combined instrument contact D and ECM # 9 for short circuit to live.

If voltmeter reads approx. 0 volts:
^ Check lead between combined instrument contact D and ECM # 9 for short circuit to ground.




CHECK CONNECTOR
- Ignition off.
- Check 13-pin connector to left A-post (A9) connector 6, combined instrument connector contact D and ECM connector for contact resistance and oxidation.
- Connect breakout box and check control points.
- Connect ECM.
- Gear selector: neutral.
- Lift vehicle so that rear wheels are clear of ground.
- Ignition on.



- Connect a voltmeter between # 9 and # 19 on breakout box.
- Spin rear wheels.

Voltmeter should read approx. 6 volts.

If value OK:
^ Source of DTC is bad contact in connector.

If value differs:
^ Check lead between combined instrument contact D and ECM # 9 for break.




INTERMITTENT FAULT
Check leads and connectors
- Fault trace combined instrument and VSS sensor circuit for intermittent fault.
- Check 13-pin connector to left A-post (A9) connector 6, combined instrument and ECM connector for bad contact, contact resistance and oxidation.
- Check lead between ECM # 9 and combined instrument contact D for intermittent break, intermittent short circuit to ground and intermittent short circuit to live.