P0012
DTC P0012
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC P0012
- Intake Camshaft Position (CMP) System Performance - Retarded
Diagnostic Fault Information
Circuit/System Description
The CMP actuator solenoid enables the powertrain control module (PCM) to change the intake camshaft timing while the engine is running. The CMP actuator solenoid contains a spool valve that controls the advance of the camshaft. The CMP actuator solenoid valve is controlled by a pulse width modulated (PWM) signal from the PCM. The CMP sensor monitors the camshaft position or the camshaft angle, and compares that position or phase to the crankshaft position (CKP) sensor signal. The PCM determines whether the camshaft angle is correct by comparing the actual camshaft position to the target camshaft position. By continuously analyzing the input of the CMP sensor and the CKP sensor the PCM can detect a fault in the CMP actuator system.
Conditions for Running the DTC
* DTCs P0100, P0101, P0102, P0103, P0115, P0116, P0117, P0118, P0125, P0335, P0339, P0340, P0341, P0351, P0352, P0353, P0354 are not set.
* Battery voltage is greater than 11 volts.
* The engine speed is between 500-4,000 RPM.
* The engine coolant temperature (ECT) is between 75-100°C (167-212°F).
* The vehicle speed is greater than 64 km/h (40 mph) for greater than 3 minutes.
* DTC P0012 runs once per drive cycle when the above conditions are met.
Conditions for Setting the DTC
* The PCM does not detect a change in the camshaft timing.
* The PCM detects that the camshaft timing is fixed.
* Either of the above conditions occurs twice when the CMP actuator solenoid is activated.
Action Taken When the DTC Sets
DTC P0012 is a type B DTC.
Conditions for Clearing the DTC
DTC P0012 is a type B DTC.
Diagnostic Aids
* Inspect for any recent engine mechanical repairs. An incorrectly timed or incorrectly installed camshaft can cause a DTC P0012 to set.
* Inspect the CMP sensor reluctor for a damaged tooth. A damaged reluctor can cause an incorrect CMP sensor reading that may set a false DTC P0012.
* If a DTC P0012 and P0010 are both present, test for a condition in the CMP actuator solenoid control circuits.
* Electrical resistance in the CMP actuator solenoid control circuits can affect solenoid spool valve movement and cause a DTC P0012 to set.
* An intermittent DTC P0012 can be caused by a loss in the oil supply to the CMP solenoid valve or the CMP actuator assembly.
Reference Information
Schematic Reference
Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Camshaft Actuator System Description (Camshaft Actuator System Description)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
Note: All CMP actuator system DTCs must be cleared before the CMP actuator solenoid scan tool output control is enabled.
1. Engine running at normal operating temperature, command the CMP actuator solenoid ON with the scan tool. The engine should run rough or stall.
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the camshaft position (CMP) actuator solenoid.
2. Ignition OFF, test for less than 10 ohm between the CMP low control circuit terminal 2 and ground G104.
• If greater than the specified range, test the CMP low control circuit for an open/high resistance. If the circuit tests normal, replace the PCM.
3. Disconnect the PCM harness connector X2 at the PCM.
4. Ignition ON, test for infinite resistance between the CMP low control circuit terminal 2 and ground G104.
• If less than the specified range, repair the short to ground in the CMP low control circuit.
5. Engine running, connect the CMP actuator solenoid to B+ and ground with a pair of 10 A fused jumper wires. Verify the engine runs rough or stalls.
• If the engine does not run rough or stall, remove the CMP actuator solenoid and verify the solenoid plunger moves 3 mm (0.125 in) when connected to B+ and ground. If the solenoid plunger moves less than the specified range, test or replace the CMP actuator solenoid. If the solenoid plunger moves greater than the specified range, test the following conditions:
* A plugged or restricted CMP actuator solenoid oil filter
* A blockage or restriction in the CMP actuator system oil passages
* Incorrect operation of the CMP actuator assembly-Refer to Camshaft Position Actuator Locking Pin Adjustment (11. Camshaft Position Actuator Locking Pin Adjustment).
* Correct engine valve timing-Refer to Symptoms - Engine Mechanical (Symptoms - Engine Mechanical).
6. Test the solenoid high control circuit terminal 1 for high resistance. If the circuit tests normal, replace the PCM.
7. If all circuits test normal, test or replace the CMP actuator solenoid.
Component Testing
1. Ignition OFF, disconnect the harness connector of the CMP actuator solenoid.
2. Test for 6-8 ohm at 20°C (68°F) between the actuator solenoid terminals.
• If not within the specified range, replace the CMP actuator solenoid.
3. Test for infinite resistance between each terminal of the CMP actuator solenoid and the CMP actuator solenoid housing.
• If less than the specified value, replace the CMP actuator solenoid valve.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Camshaft Position Actuator Solenoid Valve Replacement (Camshaft Position Actuator Solenoid Valve Replacement)
* Camshaft Position Actuator Solenoid Valve Filter Replacement (Camshaft Position Actuator Solenoid Valve Filter Replacement)
* Camshaft Position Actuator Locking Pin Adjustment (11. Camshaft Position Actuator Locking Pin Adjustment)
* Control Module References (Programming and Relearning) for control module replacement, setup, and programming