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 P0016: Crankshaft Position (CKP) Camshaft Position (CMP) Correlation

Circuit/System Description

The engine control module (ECM) uses the crankshaft position (CKP) sensor and the camshaft position (CMP) sensor pulses to monitor the correlation between the crankshaft and the camshaft position. The crankshaft reluctor wheel consists of a 60-tooth pattern with 2 teeth missing for the reference gap. Each tooth is evenly spaced 6 degrees apart, except for the reference gap. The camshaft reluctor wheel has 4 teeth, 2 narrow, and 2 wide. The 4 trailing edges of each tooth are evenly spaced at 90 degrees apart around the circumference of the camshaft sprocket. With the engine running, and the CMP actuator in the parked position, the ECM expects the camshaft signal pulses to occur 36 crankshaft degrees before top dead center (BTDC) for cylinder number 1, and every 90 degrees thereafter.

Conditions for Running the DTC

    • DTC P0335, P0336, P0340, P0341, P0641, or P0651 is not set.
    • The engine is running.
    • The engine speed is less than 1,200 RPM, and the CMP actuator is commanded to the parked position.
    • The DTC runs continuously when the above conditions are met.

Conditions for Setting the DTC

The cam signal falling edge is more than minus 11 degrees or more than plus 14 degrees from the corresponding crank signal falling edge. This condition is equal to the camshaft gear being either advanced or retarded by 1 tooth.

Action Taken When the DTC Sets

    • DTC P0016 is a Type B DTC.
    • The CMP actuator is commanded to the park position.

Conditions for Clearing the DTC

DTC P0016 is a Type B DTC.

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. Start the engine.
  2. Allow the engine to reach normal operating temperature.
  3. Allow the engine to idle.
  4. With a scan tool, monitor the Desired CMP, CMP Angle, and the CMP Variance parameters. All 3 parameters should display less than 1 degree.
  5. Using the scan tool output control function, command the CMP actuator to 25 degrees. The Desired CMP and the CMP Angle parameter should display 25 degrees. The CMP Variance Angle will rise for 2-3 seconds until the Desired and Actual parameters values match, then the CMP Variance parameter should return to zero degrees.
  6. If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the Conditions For Running The DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data list.

Circuit/System Testing

Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

  1. Inspect the engine front cover area, or review the service history of the vehicle for any recent repairs involving the timing chain, timing chain tensioner, camshaft, crankshaft, camshaft actuator, or sprockets.
  2. If recent repairs were made, refer to Timing Chain and Sprocket Replacement , and inspect the timing chain, timing chain tensioner, and both sprockets for proper timing alignment or indexing.

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

  3. Monitor the engine oil pressure parameter value with a scan tool. The engine oil pressure must be at or above the minimum hot oil pressure values. Refer to Engine Mechanical Specifications .
  4. If the engine oil pressure is low, correct the cause of the low oil pressure condition first.
  5. Remove the engine front cover, refer to Engine Front Cover Removal and inspect the timing chain, timing chain tensioner, and sprockets for wear or damage.
  6. If any components are worn or damage, replace as necessary. If the all the components test normal, replace the CMP actuator assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Camshaft Position Actuator Cleaning and Inspection