P0018

DTC P0018

DTC DESCRIPTORS

DTC P0016
Crankshaft Position (CKP) - Intake Camshaft Position (CMP) Correlation Bank 1

DTC P0017
Crankshaft Position (CKP) - Exhaust Camshaft Position (CMP) Correlation Bank 1

DTC P0018
Crankshaft Position (CKP) - Intake Camshaft Position (CMP) Correlation Bank 2

DTC P0019
Crankshaft Position (CKP) - Exhaust Camshaft Position (CMP) Correlation Bank 2

CIRCUIT/SYSTEM DESCRIPTION
The camshaft position (CMP) actuator system enables the engine control module (ECM) to change the timing of the camshafts while the engine is operating. The ECM sends an electrical signal to the CMP actuator solenoids through the control circuits when a camshaft timing change is desired. The low reference circuit is used as a return. The CMP actuator solenoid uses electromagnetic force to pull on the plunger of the oil control valve. The oil control valve will port the pressurized engine oil to either the advancing or retarding chambers of the CMP actuator. The CMP actuator changes the camshaft position relative to the crankshaft position. If the ECM detects the difference between the desired camshaft position and the actual camshaft position angles is more than 12 degrees, DTC P0016, P0017, P0018, or P0019 will set.

CONDITIONS FOR RUNNING THE DTC
- DTCs P0010, P0011, P0013, P0014, P0020, P0021, P0023, P0024, P0335, P0336, P0340, P0341, P0345, P0346, P0365, P0366, P0390, P0391, P2088, P2089, P2090, P2091, P2092, P2093, P2094, P2095 are not set.
- The engine is running.
- The calculated oil temperature is between -10°C to +150°C (+14°F to +302°F).
- The oil pressure is greater than 105 kPa (15 psi).
- The Low Oil Switch parameter is 0.
- The battery voltage is between 11-16 volts.
- The CMP actuator is commanded to the park position or to its full travel.
- DTC P0016, P0017, P0018, or P0019 runs continuously when the above conditions are met.

CONDITIONS FOR SETTING THE DTC
The ECM detects the difference between the desired camshaft position and the actual camshaft position angles is more than 12 degrees for more than 3.6 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

CIRCUIT/SYSTEM VERIFICATION

IMPORTANT: If you cannot duplicate the condition, operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

1. Operate the vehicle at idle and at various engine speeds and load ranges while observing the CMP Variance, Desired CMP, and CMP Angle parameters with a scan tool.
2. All three parameters should remain less than or equal to 1 degree at idle. The CMP Variance should remain less than or equal to 1 degree unless the CMP actuator is being commanded. If the CMP actuator is moved, the CMP Variance will rise for 1-2 seconds until the CMP Angle parameter matches the Desired CMP parameter. The CMP Variance should again return to less than or equal to 1 degree.
- If the CMP Variance remains more than 1 degree for more than 3 seconds, continue with the Circuit/System Testing.

CIRCUIT/SYSTEM TESTING
Repair one of the following conditions with the camshaft timing drive components:
1. With the ignition OFF, inspect the engine or review the service history of the vehicle for any recent repairs involving the timing chain, camshaft, or crankshaft.
- If recent repairs were made, refer to Camshaft Timing Drive Chain Alignment Diagram and inspect the timing chain and sprockets for proper alignment.
2. The supply of clean pressurized engine oil to the CMP actuator is critical to CMP actuator performance. Review the service history of the vehicle for extended intervals between oil changes. Inspect the engine oil for the following:
- Viscosity breakdown
- Incorrect viscosity or contains aftermarket additives
- Low level
- Debris or other contaminants
- Mixed with engine coolant
- Low pressure
- If the engine oil is old, burnt, contains additives, or is not the correct viscosity, change the oil and filter.
- If the engine oil level is low, refer to Oil Leak Diagnosis or Oil Consumption Diagnosis to determine the cause for the loss of oil, and repair as necessary.
- If the engine oil is contaminated or contains debris, determine the cause, and remove the timing chain, CMP actuator, and sprockets.
- If the engine oil is mixed with coolant, refer to Coolant in Engine Oil to determine the cause, and repair as necessary.
- If the engine oil pressure is low, refer to Oil Pressure Diagnosis and Testing to determine the cause, and repair as necessary.
3. Remove the engine front cover, refer to Engine Front Cover Disassemble and inspect the timing chain, tensioner, and sprockets for proper alignment, wear or damage.
- If any parts are worn or damaged, replace as necessary.
- If everything else tests normal, replace the CMP actuator.

REPAIR INSTRUCTIONS
The use of oil system cleaners and additives is not recommended. Such cleaners contain strong detergents that may adversely react with seals and other engine components.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests