GM Service Manual Online
For 1990-2009 cars only

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 Descriptors

DTC P0010: Intake Camshaft Position (CMP) Actuator Solenoid Control Circuit

DTC P0013: Exhaust Camshaft Position (CMP) Actuator Solenoid Control Circuit

DTC P2088: Intake Camshaft Position (CMP) Actuator Solenoid Control Circuit Low Voltage

DTC P2089: Intake Camshaft Position (CMP) Actuator Solenoid Control Circuit High Voltage

DTC P2090: Exhaust Camshaft Position (CMP) Actuator Solenoid Control Circuit Low Voltage

DTC P2091: Exhaust Camshaft Position (CMP) Actuator Solenoid Control Circuit High Voltage

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Intake CMP Actuator Solenoid Control

P0010, P2088

P0010

P0010, P2089

P0011

Intake CMP Actuator Ignition 1 Voltage

--

P0010

--

--

Exhaust CMP Actuator Solenoid Control

P0013

P0013

P0013

P0014

Exhaust CMP Actuator Ignition 1 Voltage

--

P0013

--

--

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 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 driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The ECM detects an open, short to ground, or a short to voltage on the high control circuit or an open on the low reference circuit for more than 0.25 second.

Action Taken When the DTC Sets

DTCs P0010, P0013, P2088, P2089, P2090 and P2091 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTCs P0010, P0013, P2088, P2089, P2090 and P2091 are Type B DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Camshaft Actuator System Description

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ensure the vehicle has the proper oil viscosity.
  2. Observe the engine oil level. The engine oil level should be within the operating range.
  3. Allow the engine to reach operating temperature.
  4. Increase the engine speed to 1,500 RPM.
  5. Command each CMP actuator to 25 percent. The CMP actuator angle desired parameter should match the CMP actuator actual parameter.
  6. 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 data.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the Q6 CMP actuator solenoid.
  2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 1 and ground.
  3. If the test lamp does not illuminate, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test all the components connected to the ignition circuit and replace as necessary.
  4. Command the CMP Actuator Sol. ON with a scan tool. Verify the scan tool CMP actuator solenoid status is OK.
  5. If not the specified value, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
  6. Install a 3A fused jumper wire between the control circuit terminal A and the low reference circuit terminal B. Command the CMP Actuator Sol. ON with a scan tool. Verify the scan tool CMP actuator solenoid status is Fault.
  7. If not the specified value, test the control circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  8. Determine that the vehicle has the correct engine oil. Refer to Service and Appearance Care in the owner's manual.
  9. If the engine oil life system monitor displays the Change Oil Soon message, the engine oil is more than one year old, contains additives, or is not the correct viscosity, change the oil.
  10. Test the engine oil pressure. Refer to Oil Pressure Diagnosis and Testing.
  11. If the oil pressure is low, correct the low pressure first.
  12. Inspect each CMP actuator solenoid valve assembly for the following:
  13. • Torn screens
    • Debris on the screens
    • Debris clogging the oil ports
    • Missing screens
    • Oil seepage at the solenoid connector pins
  14. Inspect for the following conditions:
  15. • Excessive timing chain play
    • Proper installation of the CMP actuator assembly
  16. If all circuits test normal, test or replace the Q6 CMP actuator solenoid.

Component Testing

  1. Measure the resistance of each CMP actuator solenoid valve assembly. Resistance should be between 8-12Ω.
  2. Connect a jumper wire between the CMP actuator low reference circuit at the solenoid and a good ground. Connect a fused jumper wire to the CMP actuator high control circuit at the solenoid. Momentarily touch the fused jumper to B+. Observe the spool valve inside the CMP actuator. The spool valve should move from fully closed to fully opened position.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Camshaft Position Actuator Solenoid Valve Replacement
    •  Control Module References for replacement, setup, and programming