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DTC P0011, P0014, P0021, OR P0024 > DIAGNOSTIC INSTRUCTIONS
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC P0011, P0014, P0021, OR P0024 > DTC DESCRIPTORS
DTC P0011
Intake Camshaft Position (CMP) System Performance Bank 1
DTC P0014
Exhaust Camshaft Position (CMP) System Performance Bank 1
DTC P0021
Intake Camshaft Position (CMP) System Performance Bank 2
DTC P0024
Exhaust Camshaft Position (CMP) System Performance Bank 2
DTC P0011, P0014, P0021, OR P0024 > CIRCUIT/SYSTEM DESCRIPTION
The camshaft position (CMP) actuator is attached to each camshaft and is hydraulically operated in
order to change the angle of the camshaft relative to crankshaft position (CKP). The CMP actuator
solenoid is controlled by the engine control module (ECM). The ECM sends a pulse width modulated 12Āvolt signal to each CMP actuator solenoid. The solenoid controls the amount of engine oil flow to the
CMP actuator by extending a pintle within the solenoid. The pintle acts against a spool valve in the CMP
actuator mechanism which is attached to the front of each camshaft. As the spool valve is moved, oil is
directed to the CMP actuator, which rotates the camshaft. The CMP actuator can change the cam angle
a maximum of 27 degrees.
DTC P0011, P0014, P0021, OR P0024 > CIRCUIT/SYSTEM VERIFICATION
IMPORTANT: The supply of clean pressurized engine oil
to the CMP actuator is essential to CMP actuator performance.
1. Observe the engine oil level. The engine oil level should be within operating range. Refer to
Approximate Fluid Capacities .
2. Ensure that the vehicle has the correct engine oil and is not old, burnt or contains additives. Refer to
Checking Things Under the Hood in Service and Appearance Care within the Owner's Manual.
YMMS: Feb 25, 2021
Engine: 3.6L Eng License:
VIN: Odometer:
2008 GMC Acadia SLE
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1. If the vehicle has the incorrect engine oil, is old, burnt, or contains additives then change the oil
and filter.
3. Test the engine oil pressure for correct operation. Refer to OIL PRESSURE DIAGNOSIS AND
TESTING .
4. Allow the engine to reach operating temperature.
5. Set the parking brake and place the vehicle in park for automatic, or neutral for manual.
6. Observe the applicable CMP variance parameter. 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 0 degrees.
IMPORTANT: The engine will run rough and may require
throttle input to keep running.
7. Command the applicable CMP actuator to 20 degrees. The Desired CMP parameter should match
the CMP Angle parameter.
DTC P0011, P0014, P0021, OR P0024 > CIRCUIT/SYSTEM TESTING
IMPORTANT: You must complete Circuit/System
Verificationī¢ before proceeding with Circuit/System Testing.
1. Test for less than 1 ohm of resistance between the applicable CMP actuator solenoid low reference
circuit and ground.
1. If greater than 1 ohm, test the low reference for an open/high resistance. If the circuit tests
normal, replace the applicable CMP actuator solenoid.
2. Test for less than 1 ohm of resistance on the applicable CMP actuator solenoid high control circuit.
1. If greater than 1 ohm, test the high control circuit for an open/high resistance. If the circuit tests
normal, replace the applicable CMP actuator solenoid.
3. Inspect the affected CMP actuator. Refer to the camshaft position actuators in CAMSHAFT TIMING
DRIVE COMPONENTS CLEANING AND INSPECTION and ENGINE FRONT COVER CLEANING
AND INSPECTION .
4. Inspect the engine timing components. Refer to SETTING CAMSHAFT TIMING .
DTC P0011, P0014, P0021, OR P0024 > COMPONENT TESTING > STATIC TEST
1. Ignition OFF, disconnect the CMP actuator solenoid harness connector at the CMP actuator solenoid.
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