Circuit/System Testing

IMPORTANT: You must perform the Circuit/System Verification first.

IMPORTANT: Incorrect engine oil viscosity, aftermarket engine oil additives, or engine oil that overdue for changing, can greatly affect the performance of the camshaft actuator.

Ignition OFF, disconnect the CMP actuator solenoid harness connector, C112.
Test for less than 1 ohm between the low reference circuit terminal E and ground on the ECM side of the harness.
- If greater than 1 ohm, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
Verify that a test lamp does not illuminate between the low reference circuit terminal E and the control circuit terminal D on the ECM side of the harness.
- If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
Remove the test lamp.
Command the CMP actuator from 0-20 degrees. Verify the scan tool CMP actuator ckt short to volts test status parameter is OK.
- If not the specified value, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
Install a 3A fused jumper wire between the control circuit terminal D and the low reference circuit terminal E on the ECM side of the harness. Command the CMP actuator to 20 degrees with a scan tool. Verify the scan tool CMP actuator ckt short to volts test status parameter is displaying Fault.
- If not the specified value, test the control circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
Remove the water pump from the engine. Refer to Water Pump Removal (RPO LY2/LC9/LY5/LMG) or Water Pump Removal (RPO LY6/L76/L9H) .
Inspect and test the remaining wire harness from C112 to the CMP solenoid for an open/high resistance, or a short to ground.
- If all circuits test normal, test or replace the CMP actuator.
- If the CMP solenoid and the circuit test normal, then refer to Camshaft Position Actuator Magnet Cleaning and Inspection and Camshaft Position Actuator Solenoid Valve Inspection (On-Vehicle) or Camshaft Position Actuator Solenoid Valve Inspection (Off-Vehicle) .