DTC 3-1-4

3-1-4 CAMSHAFT POSITION (CMP) SENSOR SIGNAL

Condition(s) for DTC
^ The CMP sensor mounted on the camshaft enables the ICM to determine the cylinder in which ignition is required. Since the camshaft describes one revolution for every two crankshaft revolutions, the sensor signal goes high and low on each alternate revolution.
^ The DTC is recorded if the signal (which is compared with the RPM sensor signal) remains continuously high or low for tour engine revolutions.

Substitute value
^ None.

Fault source(s)
^ Signal lead short-circuited to ground or supply.
^ Supply lead short-circuited to ground.
^ Open-circuit in ground lead, ground terminal, signal lead or supply lead.
^ Faulty sensor.

Fault symptom(s)
^ Engine cannot be started or stops while running.
^ Engine starts when signal is restored.

TESTING PROCEDURE





Other DTCs
^ Read other DTCs.

If MFI DTC 2-2-3 is recorded:
- Proceed to: Testing By Trouble Code / Fuel Injection System / DTC 2-2-3 Idle Air Control Valve Signal.
If MFI DTC 2-2-3 is not recorded:
- Check Status message.





Status message
^ Check current Status message.

If Status message is: Signal faulty.
- Proceed with testing procedure below.





Start engine
^ Try to START engine.

If engine starts:
- Intermittent fault.
- Proceed to: DTC 3-2-4 Camshaft Position Sensor Signal Sporadic.
If engine does not start:
- Permanent fault.
- Proceed to: PERMANENT FAULT Section below.

PERMANENT FAULT





Checking ground lead
^ Switch ON ignition.
^ Disconnect sensor.
^ Connect ohmmeter between sensor connector terminal 1 (control module side) and ground.

Instrument should indicate approx. 0 Ohms.

If reading is correct:
- Check signal lead.
If reading is incorrect:
- Check lead between ICM A15 and sensor connector terminal 1 for open-circuit.





Checking signal lead
^ Switch ON ignition.
^ Disconnect CMP sensor.
^ Connect voltmeter between sensor terminal 2 (ICM side) and ground.

Instrument should indicate approx. 5 Volts.

If reading is correct:
- Check supply lead.
If instrument indicates over 5 Volts:
- Check lead between ICM A4 and sensor connector terminal 2 for short-circuit to supply.
When fault has been corrected:
- Check sensor signal.
If instrument indicates approx. 0 Volts:
- Check resistance of signal lead to ground.





Checking supply lead
^ Switch ON ignition.
^ Disconnect sensor.
^ Connect voltmeter between sensor connector terminal 3 (ICM side) and ground.

Instrument should indicate battery voltage.

If reading is correct.
- Check sensor.
If reading is incorrect:
- Check resistance of supply lead to ground.





Checking sensor
^ Reconnect sensor (if disconnected).
^ Try to START engine.

If engine starts:
- DTC is due to poor connection in sensor connector.
- Check connector for contact resistance and oxidation.
If engine does not start:
- Try with new sensor.





Checking resistance of supply lead to ground
^ Switch OFF ignition.
^ Disconnect sensor.
^ Wait approx. 30 seconds.
^ Connect ohmmeter between sensor connector terminal 3 (ICM side) and ground.

Instrument should indicate infinite resistance (no continuity).

If reading is correct:
- Check lead between ICM A14 and sensor connector terminal 3 for open-circuit.
If reading is incorrect:
- Check lead between ICM A14 and sensor connector terminal 3 for short-circuit to ground.





Checking resistance of signal lead to ground
^ Switch OFF ignition.
^ Disconnect sensor.
^ Disconnect ICM.
^ Connect ohmmeter between sensor connector terminal 2 (ICM side) and ground.

Instrument should indicate 2 - 6K Ohms.

If resistance is approx. 0 Ohms:
- Check lead between ICM A4 and sensor connector terminal 2 for short-circuit to ground.
If resistance is infinite (no continuity):
- Check lead between ICM A4 and sensor connector terminal 2 for open-circuit.





Checking sensor signal
^ Sensor may fail if signal lead is short-circuited to supply voltage.
^ Check sensor as follows:
^ Reconnect sensor (if disconnected).
^ Erase DTC.
^ Try to START engine.

If engine does not start:
- Try with new sensor.
If engine starts:
- Sensor is intact.