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

CKP 5-Volt Reference Voltage

P0642

P0335, P0336

P0643

P0336

CKP Sensor Signal

P0335, P0336

P0335, P0336

P0335, P0336

P0336

CKP Low Reference

--

P0335, P0336

--

P0336

Typical Scan Tool Data

CKP Sensor Signal Present

Circuit

Normal Range

Short to Ground

Open

Short to Voltage

Operating Conditions: Engine Running

CKP 5-Volt Reference Voltage

Yes

No

No

No

CKP Sensor Signal

Yes

No

No

No

CKP Low Reference

Yes

--

No

No

Circuit/System Description

The hall effect crankshaft position (CKP) sensor signal indicates the crankshaft speed and position. There are 57 teeth on the front of the crankshaft sprocket, plus a sync gap. The CKP sensor will output an ON/OFF pulse as each tooth passes the sensing element. The CKP sensor is connected directly to the engine control module (ECM) by the following circuits:

    • The 5-volt reference circuit
    • The low reference circuit
    • The signal circuit

Conditions for Running the DTC

P0335

    • The engine is cranking or running.
    • The camshaft position (CMP) sensor signal is present.
    • DTC P0335 runs continuously when the above conditions are met.
    • DTCs P0642 or P0643 are not set.

P0336

    • The engine is cranking or running.
    • DTC P0336 runs continuously when the above condition is met.
    • DTCs P0642 or P0643 are not set.

Conditions for Setting the DTC

P0335

The ECM determines that there are no signal pulses from the CKP sensor.

P0336

The ECM detects CKP sensor pulses that are more than 0 but not equal to 57 teeth, and a sync gap per one crankshaft revolution.

Action Taken When the DTC Sets

DTCs P0335 and P0336 are Type A DTCs.

Conditions for Clearing the MIL/DTC

DTCs P0335 and P0336 are Type A DTCs.

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

Special Tools

J 38522 Variable Signal Generator

Circuit/System Verification

  1. If DTCs P0642 or P0643 are set, diagnose those DTCs first.
  2. The engine starts and runs.
  3. Engine running, observe the DTC information with a scan tool. DTCs P0335 or P0336 should not set.
  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 data.

Circuit/System Testing

P0335

  1. Ignition OFF and the scan tool disconnected for 90 seconds, disconnect the harness connector at the CKP sensor.
  2. Test for less than 5 ohms between low reference circuit terminal 2 of the connector and ground.
  3. If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  4. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference 1 circuit terminal 3 of the connector and ground.
  5. If less than the specified range, test the 5-volt reference 1 circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM.
    If greater than the specified range, test the 5-volt reference 1 circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  6. Test for 4.8-5.2 volts between the signal circuit terminal 1 of the connector and ground.
  7. If less than the specified range, test the signal circuit for an open/high resistance or short to ground. If the circuit tests normal, replace the ECM.
    If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  8. Ignition OFF, connect a 3A fused jumper wire between signal circuit terminal 1 of the connector and ground.
  9. Ignition ON, observe the scan tool 5-Volt Reference 1 Circuit Status parameter. The parameter should display OK.
  10. If the 5-Volt Reference 1 Circuit Status parameter does not display OK, test the signal circuit for a short to 5-volt reference. If the circuit tests normal, replace the ECM.
  11. Ignition OFF, connect the red lead of the J 38522 to the signal circuit terminal 1 of the connector. Connect the battery voltage supply to B+. Connect the black lead to ground.
  12. Set the J 38522 signal switch to 5 volts, the frequency to 5K, and the duty cycle to normal.
  13. Ignition ON, observe the CKP Sensor Signal Present parameter of the scan tool. The parameter should display YES.
  14. If the parameter does not display YES, replace the ECM.
  15. If the circuits test normal replace the CKP sensor.

P0336

  1. Ensure that the CKP sensor circuits are not routed too closely to the fuel injector wiring after-market add-on electrical equipment, solenoids, relays or motors.
  2. Ignition OFF, inspect the CKP sensor for correct installation.
  3. If the sensor is loose, inspect the sensor and the O-ring for damage, replace as necessary.

    Important: Refer to Inducing Intermittent Fault Conditions for additional instructions on inducing intermittent conditions.

  4. Engine running, observe the CKP Sensor Signal Present parameter of the scan tool while manipulating the related harnesses, connectors, and wires of the CKP sensor. The parameter should display Yes.
  5. If the parameter displays No or fluctuates between Yes and No, inspect the related harness, connector, or wire for damage or poor connectivity at or near the point of the manipulation. Repair or replace as necessary.
  6. Inspect the engine for the following conditions:
  7. • The engine oil for debris
    • The crankshaft reluctor wheel for damage or foreign material passing between the sensor and reluctor wheel
    • The timing chain, tensioner, and sprockets for wear or damage
  8. If no other condition is found, replace the CKP sensor.

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 Reluctor and Oil Pump Drive Gear Replacement