GM Service Manual Online
For 1990-2009 cars only

Circuit 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 CMP actuator solenoid signal from the ECM is pulse width modulated (PWM). The ECM controls the CMP actuator solenoid duty cycle by controlling the amount of solenoid ON time. The CMP actuator solenoid controls the advance or the retard of each camshaft. The CMP actuator solenoid controls the oil flow that applies the pressure to advance or retard the camshafts.

Ignition voltage is supplied directly to the CMP actuator solenoid. The ECM controls the solenoid by grounding the control circuit with a solid state device called a driver. The ECM compares the CMP or the camshaft angle, to the position of the crankshaft. If the ECM detects a deviation between the camshaft position target and the crankshaft position (CKP), this DTC sets.

DTC Descriptors

This diagnostic procedure supports the following DTCs.

    • 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

Conditions for Running the DTC

    • The engine is operating for more than 5 seconds.
    • The engine coolant temperature is between 0-92°C (32-198°F).
    • The calculated engine oil temperature is less than 120°C (248°F).
    • DTC P0016, P0017, P0018, and P0019 run continuously once the above conditions are met for more than 1 second.

Conditions for Setting the DTC

Condition 1

    • The ECM detects that the actual camshaft angle of a single intake camshaft is more than 20 degrees advanced in relationship to the crankshaft.
    • The ECM detects that the actual camshaft angle of a single exhaust camshaft is more than 25 degrees retarded in relationship to the crankshaft.
    • The camshafts are being commanded to the parked position.

Condition 2

    • The learned angle of an intake camshaft is more than 14.5 degrees advanced in relationship to the crankshaft.
    • The learned angle of an exhaust camshaft is more than 14.5 degrees retarded in relationship to the crankshaft.

Either condition exists for more than 10 minutes.

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 MIL/DTC

    • The control module turns OFF the malfunction indicator lamp (MIL) after 4 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.

Diagnostic Aids

    • Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
    • Inspect the engine for any recent engine mechanical repairs. An incorrectly installed camshaft, camshaft actuator, camshaft sensor, crankshaft sensor, or timing chain can cause this DTC to set.
    • An actuator that is in the full advance or retard position can cause this DTC to set.
    • For an intermittent condition, refer to Intermittent Conditions .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step determines if there is a condition present.

  2. The listed DTCs may cause this DTC to set.

  3. Inspect the engine for any recent engine mechanical repairs. An incorrectly installed camshaft or timing chain can cause this DTC to set.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

  1. Start the engine.
  2. Allow the engine to reach the normal operating temperature.
  3. Allow the engine to idle for the specified amount of time.
  4. Observe the DTC information with a scan tool.

Does the scan tool display DTC P0016, P0017, P0018, or P0019 failed this ignition?

10 Minutes

Go to Step 4

Go to Step 3

3

  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. 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.

Did the DTC fail this ignition?

--

Go to Step 4

Go to Diagnostic Aids

4

Observe the DTC Information with a scan tool.

Does the scan tool display that DTC P0010, P0013, P0020, P0023, P0335, P0336, P0338, P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, P0393, P2088, P2089, P2090, P2091, P2092, P2093, P2094, or P2095 also failed this ignition?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 5

5

Repair one of the following conditions:

    • For the correct installation of the camshaft sensors
    • For the correct installation of the crankshaft sensor
    • For a timing chain tensioner condition
    • For an incorrectly installed timing chain
    • For excessive play in the timing chain
    • For a timing chain that jumped teeth

Refer to Camshaft Timing Drive Chain Alignment Diagram and Camshaft Timing Drive Components Cleaning and Inspection in Engine Mechanical-3.6L (LY7).

Did you complete the repair?

--

Go to Step 6

--

6

  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. 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.

Did the DTC fail this ignition?

--

Go to Step 2

Go to Step 7

7

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK