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 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, P0643

P0335, P0336

P0335, P0336, P0341, P0642, 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

Present

No

No

No

CKP Sensor Signal

Present

No

No

No

CKP Low Reference

Present

--

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 window 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.

P0336

    • The engine is cranking or running.
    • DTC P0336 runs continuously when the above condition is met.

Conditions for Setting the DTC

P0335

The ECM determines no signal from the CKP sensor for less than 8 seconds.

P0336

The ECM determines that the CKP sensor signal is out of range for less than 2 seconds.

Action Taken When the DTC Sets

    • The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/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

    • An intermittent CKP sensor signal may cause DTC P0336 to set. Wiggle the wiring harness with the engine running and observe the CKP Sensor Pulses Missed parameter on the scan tool. If the parameter indicates anything other than 0, there is an intermittent condition.
    • Inspect for insufficient fuel.

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

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions

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

  1. With the key ON and the CKP sensor disconnected, measure the voltage between the 5-volt reference and a good ground and observe that the DMM measures 4.98-5.02 volts.
  2. If the DMM does not measure 4.98-5.02 volts, test the 5-volt reference for an open or high resistance. If the circuits test normal, replace the control module.
  3. With the key ON and the CKP sensor disconnected, measure the voltage between the 5-volt reference circuit and the low reference circuit, and observe that the DMM measures 4.98-5.02 volts.
  4. If the DMM does not measure 4.98-5.02 volts, test the low reference for an open or high resistance. If the circuits test normal, replace the control module.
  5. With the key ON and the CKP sensor disconnected, connect a fused jumper wire to the signal circuit and momentarily and repeatedly probe the low reference circuit, and observe that the Crank Signal Present and engine RPM parameters change.
  6. If the crank signal parameter and engine RPM does not change, test the signal circuit for an open, high resistance, a short to ground, a short to voltage. If the circuits test normal, replace the control module.
  7. 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.
  8. Inspect the CKP sensor for physical damage, loose or improper installation, excessive air gap, or foreign material passing between the sensor and the reluctor wheel.
  9. Inspect the CKP reluctor wheel for physical damage, improper installation, or excessive endplay or looseness.
  10. 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