Circuit/System Testing
- Ignition OFF, disconnect the 16-way engine harness to fuel injector harness connector.
- Test for less than 1 ohm between ECM side of the low reference circuit and ground.
- If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
- Ignition ON, test for 4.8-5.2 volts between the ECM side of the 5-volt reference circuit and ground.
- If less than the specified range, test the 5-volt reference circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM.
- If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
- Ignition ON, test for 4.8-5.2 volts between the ECM side of the signal circuit and ground.
- If less than the specified range, test the signal circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM.
- If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
- Ignition ON, using a jumper wire connected to ground, momentarily touch the CMP sensor signal circuit repeatedly. The CMP active counter parameter should increment.
- If the CMP active counter does not increment, replace the ECM.
- Ignition OFF, inspect the wiring harness, from the 16-way connector to the CMP sensor, for any damage, opens, or shorts.
- If the circuits test normal, replace the CMP sensor.