GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2004 🢒 XLR 🢒 Engine 🢒 Engine Controls - 4.6L (LH2) 🢒 DTC P0016, P0017, P0018, or P0019

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 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 to +150°C (14-302°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.

Conditions for Setting the DTC

The ECM detects one of the following conditions:

    • The ECM detects the difference between the desired camshaft position and the actual camshaft position angles is more than 12 degrees.
    • The condition exists for more than 1 second.

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.

The CMP Actuator System will be disabled until the end of the ignition cycle.

Conditions for Clearing the MIL/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.

Diagnostic Aids
    • Inspect the engine for any recent engine mechanical repairs. An incorrectly installed camshaft, camshaft actuator, or timing chain can cause this DTC to set.
    • Inspect for a slow returning camshaft position actuator. A stuck or slow returning camshaft position actuator can cause this DTC to set.
    • If the condition is intermittent , refer to Intermittent Conditions .

Test Description

  1. This step determines if the condition is present.

    2.

  2. An incorrectly installed camshaft or timing chain can cause these DTC's 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-Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Start the engine.
  2. Allow the engine to reach the normal operating temperature.
  3. Observe the DTC information with a scan tool.

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

--

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

Repair one of the following conditions with the camshaft timing drive components system:

    • A stuck or sticking camshaft position actuator oil control valve
    • A stuck camshaft position actuator
    • A slow returning camshaft position actuator
    • A misaligned timing chain
    • An incorrectly installed timing chain
    • Excessive play in the timing chain
    • A timing chain that jumped teeth
    • A timing chain tensioner condition

Refer to Camshaft Timing Drive Chain Alignment Diagram and Camshaft Timing Drive Components Cleaning and Inspection in Engine Mechanical.

Did you find and correct the condition?

--

Go to Step 6

Go to Step 5

5

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

--

Go to Step 6

--

6
  1. Clear the DTC's 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 DTC's that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information

System OK