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 provide an overview of each diagnostic category.

DTC Descriptors

DTC P0335: Crankshaft Position (CKP) Sensor Circuit

DTC P0336: Crankshaft Position (CKP) Sensor Performance

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

5-Volt Reference Circuit

P0335, P0651, P2135

P0335, P0336

P0651

--

CKP Sensor Signal Circuit

P0335

P0335

P0335

P0336

Low Reference Circuit

P0335

P0335

--

--

Typical Scan Tool Data

CKP Active Counter

Circuit

Normal Range

Short to Ground

Open

Short to Voltage

Operating Conditions: Engine Running

5-Volt Reference Circuit

1

2

2

2

CKP Sensor Signal Circuit

1

2

2

2

Low Reference Circuit

1

2

2

--

  1. Incrementing from 0-255
  2. Stopped incrementing and at a fixed value

Circuit/System Description

The crankshaft position (CKP) sensor circuits consist of an engine control module (ECM) supplied 5-volt reference circuit, low reference circuit and an output signal circuit. The CKP sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes of the teeth and slots of a 58-tooth reluctor wheel on the crankshaft. Each tooth on the reluctor wheel is spaced at 60-tooth spacing, with 2 missing teeth for the reference gap. The CKP sensor produces an ON/OFF DC voltage of varying frequency, with 58 output pulses per crankshaft revolution. The frequency of the CKP sensor output depends on the velocity of the crankshaft. The CKP sensor sends a digital signal, which represents an image of the crankshaft reluctor wheel, to the ECM as each tooth on the wheel rotates past the CKP sensor. The ECM uses each CKP signal pulse to determine crankshaft speed and decodes the crankshaft reluctor wheel reference gap to identify crankshaft position. This information is then used to determine the optimum ignition and injection points of the engine. The ECM also uses CKP sensor output information to determine the camshaft relative position to the crankshaft, to control camshaft phasing, and to detect cylinder misfire.

Conditions for Running the DTC

    • DTC P0340, P0341, P0641 or P0651 is not set.
    • The engine is cranking or running.
    • The DTC runs continuously when the above conditions are met.

Conditions for Setting the DTC

P0335

       Important: The ECM detects engine movement by sensing the airflow through the MAF sensor is more than 3 g/s, or by sensing camshaft position (CMP) sensor pulses.

    • The ECM detects that the starter is commanded on and the engine has been cranking for more than 4 seconds without a CKP sensor pulse.
        OR
    • The ECM detects that the engine is running, but does not receive a CKP sensor pulse for 2 of 10 engine revolutions.
        OR
    • The ECM detects that the engine is running, but does not sync.

P0336

       Important: The ECM detects engine movement by sensing the airflow through the MAF sensor is more than 3 g/s, or by sensing CMP sensor pulses.

    • The ECM detects that the engine is running, but receives less than 55 or more than 61 CKP sensor pulses each engine revolution for 8 of 10 engine revolutions.
        OR
    • The ECM detects that the engine is running, but more than 19 resyncs occur within 25 seconds.

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 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 CKP sensor connector and the ECM connector for corrosion.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

    •  Engine Control Module Connector End Views
    •  Engine Controls Connector End Views

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

    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification

  1. With the engine running, observe the Engine Speed parameter with the scan tool. The parameter should display the current engine speed matching the CMP Sensor parameter.
  2. If the Engine Speed parameter displays a value other than the current engine speed, continue with Circuit/System Testing.
  3. With the engine running, observe the CKP Active Counter parameter with the scan tool. The counter should increment from 0-255 and over again with each CKP sensor pulse.
  4. If the CKP Active Counter displays a value of 0, or a fixed value, continue with Circuit/System Testing.
  5. Turn OFF the ignition for 60 seconds.
  6. Start the engine. Do not cycle the ignition until this test is completed.
  7. Operate the vehicle in various operating conditions within the Conditions for Running the DTC and observe the CKP Resync Counter parameter with the scan tool. The CKP Resync Counter should remain at 0 counts.
  8. If the CKP Resync Counter increments, continue with Circuit/System Testing.
  9. Engine running, observe the DTC information with a scan tool. DTCs P0335 or P0336 should not set.
  10. 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. With the ignition OFF, Inspect the engine wiring harnesses carrying the CKP sensor circuits for the following conditions:
  2. • Close routing of secondary ignition wires
    • Close routing of aftermarket electrical equipment
    • Close to solenoids, motors, and relays
    Correct any wire harness routing or component placement conditions, if it is determined to be a possible source of electrical interference.
  3. Disconnect the CKP sensor connector.
  4. With the ignition ON and the engine OFF, measure for 4.8-5.2 volts at the connector between the 5-volt reference circuit of the CKP sensor and a good ground.
  5. If the voltage is less than 4.8 volts, test for an open in the 5-volt reference circuit between the ECM and the CKP sensor connector. If the circuit tests normal, replace the control module.
  6. With the ignition ON and the engine OFF, measure for 4.8-5.2 volts at the connector between the CKP sensor signal circuit and a good ground.
  7. If the voltage is less than 4.8 volts, test for an open or a short to ground in the CKP sensor signal circuit between the ECM and the CKP sensor connector. If the circuit tests normal, replace the control module.
    If the voltage is more than 5.2 volts, test for a short to voltage in the CKP sensor signal circuit between the ECM and the CKP sensor connector. If the circuit tests normal, replace the control module.
  8. With the ignition ON and the engine OFF, measure for 1-3 mA at the connector between the CKP sensor signal circuit and a good ground.
  9. If the amperage is more than 3 mA, test the CKP sensor signal circuit for a short to the 5-volt reference circuit between the ECM and the CKP sensor connector. If the circuit tests normal, replace the control module.
  10. Connect a fused jumper wire to a good ground.
  11. With the ignition ON and the engine OFF, observe the CKP Active Counter parameter on the scan tool.
  12. Touch the jumper wire to the CKP sensor signal circuit repeatedly at the connector. The CKP Active Counter parameter should increment.
  13. If the CKP Active Counter parameter does not increment, replace the ECM.
  14. With the ignition ON and the engine OFF, measure for B+ at the connector between the low reference circuit of the CKP sensor and the battery positive post.
  15. If the voltage measured between the low reference circuit and the battery positive post is not the same as voltage measured between a good ground and the battery positive post, test for an open/high resistance in the low reference circuit between the ECM and the CKP sensor connector. If the circuit tests normal, replace the control module.
  16. With the ignition OFF, inspect the CKP sensor for looseness. Remove the CKP sensor from the engine, inspect the sensor and the O-ring for damage.
  17. Repair or replace the CKP sensor, if necessary.
  18. Reconnect the connector to the CKP sensor.
  19. Turn ON the ignition, with the engine OFF.
  20. While observing the CKP Active Counter parameter on the scan tool, pass a steel object by the tip of the sensor repeatedly. The CKP Active Counter parameter should increment.
  21. If the parameter remains at 0 or another fixed value, replace the CKP sensor.
  22. With the ignition OFF, remove the oil pan. Refer to Oil Pan Replacement and inspect the engine oil for debris and the crankshaft reluctor wheel for damage or debris stuck in the teeth.
  23. If debris is found in the engine oil, inspect the engine components to determine the cause.
    If the crankshaft reluctor wheel is damaged, replace the crankshaft.
  24. With the ignition OFF, remove the engine front cover. Refer to Engine Front Cover Removal and inspect the timing chain, tensioner, and sprockets for wear or damage.
  25. If any parts are worn or damaged, replace as necessary.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Crankshaft Position Sensor Replacement
    •  Control Module References for ECM replacement, setup, and programming
    •  Crankshaft and Bearing Removal
    •  Crankshaft and Bearing Cleaning and Inspection
    •  Crankshaft and Bearing Installation