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 Descriptor

DTC P0011: Camshaft Position (CMP) System Performance

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

CMP Actuator Solenoid High Control

P0010

P0010

P0010

P0011

CMP Actuator Solenoid Low Reference

--

P0010, P0011

--

--

Typical Scan Tool Data Table

CMP Command

Display Parameters

Short to Ground

Open/High Resistance

Short to Voltage

Operating Conditions: Engine speed greater than 900 RPMs in Park

Parameter Normal Range: 0-100%

CMP Command

0%

0%

0%

Desired CMP

Display Parameters

Short to Ground

Open/High Resistance

Short to Voltage

Operating Conditions: Engine speed greater than 900 RPMs in Park

Parameter Normal Range: 0-31°

Desired CMP

CMP Angle

Display Parameters

Short to Ground

Open/High Resistance

Short to Voltage

Operating Conditions: Engine speed greater than 900 RPMs in Park

Parameter Normal Range: 0-31°

CMP Angle

CMP Variance

Display Parameters

Short to Ground

Open/High Resistance

Short to Voltage

Operating Conditions: Engine speed greater than 900 RPMs in Park

Parameter Normal Range:

CMP Variance

Circuit/System Description

The camshaft position (CMP) actuator solenoid is controlled by the engine control module (ECM). The ECM sends a 12 volt, pulse width modulated (PWM) signal to the CMP actuator solenoid. The CMP actuator solenoid positions the CMP actuator spool valve to control the amount of pressurized engine oil, which enters into the CMP actuator assembly. A low reference wire circuit between the CMP actuator solenoid and the ECM completes the electrical circuit. The frequency of the pulse width modulated signal is fixed at 150 Hz. The ECM can only command the CMP actuator to retard the valve timing from the camshaft park position, or advance the valve timing back to the park position. The total range of valve timing command is 31 degrees as measured at the camshaft, or 62 degrees as measured at the crankshaft.

Conditions for Running the DTC

    • DTC P0010, P0016, P0335, P0336, P0340, or P0341 is not set.
    • The engine is running.
    • The system voltage is between 11-18 volts.
    • The CMP actuator is enabled and commanded greater than 0 degrees.
    • The power take off (PTO) is not active.
    • The rate of change in the camshaft position is less than, 7.5 degrees for 3.35 seconds.
    • DTC P0011 runs continuously when the above conditions are met.

Conditions for Setting the DTC

    • The ECM detects resistance greater than 2 ohms on the low reference circuit.
    • The ECM detects that the CMP Angle position is more than 8 degrees difference than the Desired CMP position.

Action Taken When the DTC Sets

    • DTC P0011 is a Type B DTC.
    • The CMP actuator is commanded to the park position.

Conditions for Clearing the DTC

DTC P0011 is a Type B DTC.

Diagnostic Aids

This test procedure requires that the vehicle battery has passed a load test and is completely charged. Refer to Battery Inspection/Test.

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

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Observe the engine oil level. The engine oil level should be within the operating range on the oil indicator stick.
  2. Start the engine; allow the engine to reach normal operating temperature.
  3. Monitor the engine oil pressure parameter value with the scan tool. The engine oil pressure must be at or above the minimum hot oil pressure values. Refer to Engine Mechanical Specifications.
  4. Using the output control function of the scan tool, command the CMP actuator solenoid to 25 degrees. The CMP Desired parameter value should match the CMP Angle parameter value.
  5. Observe the CMP Variance value, on the scan tool. The CMP Variance value will increment for several seconds, until the CMP Angle value matches the Desired CMP value. The CMP Variance value should then return to zero degrees.
  6. Operate the vehicle within the Conditions for Running the DTC, to verify the DTC does not reset. You may also operate the vehicle within the conditions that are captured in the Freeze Fame/Failure Records Data List.

Circuit/System Testing

    Important: You must perform the Circuit/System Verification first.

    Important: Incorrect engine oil viscosity, aftermarket engine oil additives, or engine oil that overdue for changing, can greatly affect the performance of the camshaft actuator.

  1. Ignition OFF, disconnect the CMP actuator solenoid harness connector, C112.
  2. Test for less than 1 ohm between the low reference circuit ECM side, terminal E and ground.
  3. If greater than 1 ohm, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  4. Remove the water pump from the engine. Refer to Water Pump Removal.
  5. Inspect and test the remaining wire harness from C112 to the CMP solenoid for an open/high resistance, or a short to ground.
  6. If the circuit tests normal, perform the component testing for the CMP actuator solenoid.
    If the CMP solenoid and the circuit test normal, then refer to Camshaft Position Actuator Magnet Cleaning and Inspection and Camshaft Position Actuator Solenoid Valve Inspection.

Component Testing

Static Test

Important: You must perform the Circuit/System Testing first.

Test for 5.9 and 6.9 ohms at 20°C (68°F) between the solenoid control terminal 2 and the low reference terminal 1 at the CMP actuator solenoid.

If the resistance is not within the specified range, then replace the CMP actuator solenoid. Refer to Camshaft Position Actuator Magnet Replacement.

Dynamic Test

Important: Do not allow electrical current to flow through the CMP actuator solenoid for more than 1-2 seconds, or damage to the solenoid may occur.

Point the CMP actuator solenoid vertically, towards a shop towel. Connect one end of a fused jumper wire to the CMP actuator solenoid control circuit terminal 2 and 12 volts. Connect a second jumper wire to the low reference circuit terminal 1 and momentarily connect to ground. The CMP actuator solenoid should immediately extend.

If the CMP actuator solenoid pintle does not extend, then replace the CMP actuator solenoid. Refer to Camshaft Position Actuator Magnet Replacement.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Camshaft Position Actuator Magnet Replacement
    •  Control Module References for ECM replacement, setup, and programming