GM Service Manual Online
For 1990-2009 cars only

Object Number: 604990  Size: SF
Engine Controls Component Views
CKP, CMP, KS and Traction Control System
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The crankshaft position(CKP) ensor is mounted in the right rear of the engine block above the starter. The CKP sensor works in conjunction with a 24X reluctor wheel mounted on the rear of the crankshaft. The CKP sensor has a B+ power supply, a ground, and a signal circuit.

As the crankshaft rotates, the reluctor wheel teeth interrupt a magnetic field produced by a magnet within the sensor. The sensor's internal circuitry detects this and produces a signal which the PCM reads. The PCM uses this signal to accurately measure crankshaft velocity which is a variable used in order to detect misfire, and control spark, and fueling.

Conditions for Running the DTC

The engine is cranking or running.

Conditions for Setting the DTC

The PCM determines that the CKP sensor signal is out of range for less than 2.0 seconds.

Action Taken When the DTC Sets

    • The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
    • The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

    • The PCM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Use a scan tool in order to clear the MIL and the DTC.

Diagnostic Aids

Important: 

   • Remove any debris from the PCM\TAC module connector surfaces before servicing the PCM\TAC module. Inspect the PCM\TAC module connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM\TAC modules.
   • For any test that requires probing the PCM or a component harness connector, use the Connector Test Adapter Kit J 35616 . Using this kit prevents damage to the harness/component terminals. Refer to Using Connector Test Adapters in Wiring Systems.

    • The following conditions may cause this DTC to set:
       - Poor connections
       - Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
       - Crankshaft reluctor wheel damage or improper installation
       - The sensor coming in contact with the reluctor wheel
       - The engine running out of fuel
       - If the crankshaft rotates backwards, this DTC sets. This condition is only with vehicles equipped with a manual transmission. This condition occurs when a vehicle is on an incline and the clutch is released and an engine stall occurs.
    • Excess crankshaft end play will cause the CKP sensor reluctor wheel to move out of alignment with the CKP sensor. This could result in any one of the following:
       - A no start
       - A start and stall
       - Erratic performance
    • An improperly installed propeller shaft could cause excess crankshaft end play.
    • For an intermittent, refer to Symptoms .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step verifies that the malfunction is present.

  2. This step tests for electromagnetic interference (EMI) on the CKP sensor circuits.

  3. Vertical lines across the face of the sensor could indicate foreign material passing between the CKP sensor and the reluctor wheel. Non vertical lines across the face of the sensor may indicate a crack in the CKP sensor. Either of these conditions causes this DTC to set.

  4. Damage to the reluctor wheel would affect the CKP sensor output. To inspect the reluctor wheel, remove the starter and rotate the crankshaft while viewing the reluctor wheel through the CKP sensor hole. If you cannot determine if the reluctor wheel is damaged, the oil pan may have to be removed.

Step

Action

Values

Yes

No

1

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Important: If DTC P0335 is also set, diagnose DTC P0335 before proceeding with this DTC.

  1. Install a scan tool.
  2. Start the engine and idle for 2 minutes.

Does the scan tool indicate that DTC P0336 failed this ignition?

--

Go to Step 3

Go to Diagnostic Aids

3

  1. Visually/Physically inspect all circuits going to the Crankshaft Position sensor for the following:
  2. • Routed too close to secondary ignition wires or components
    • Routed too close to after-market add on electrical equipment
    • Routed too close to solenoids, relays and motors
  3. If you find incorrect routing, correct the harness routing.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 4

4

  1. Inspect for poor connections at the CKP sensor. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  2. If you find a poor connection repair the terminal as necessary. Refer to Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 5

5

  1. Inspect for poor connections at the PCM for the CKP sensor circuits.
  2. If you find a poor connection repair the terminal as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 6

6

  1. Remove the CKP sensor. Refer to Crankshaft Position Sensor Replacement .
  2. Inspect the CKP sensor for signs of damage.
  3. If you find the CKP to be damaged, refer to Crankshaft Position Sensor Replacement .

Did you find and correct the condition?

--

Go to Step 9

Go to Step 7

7

  1. Inspect the CKP reluctor wheel for damage.
  2. If you find the CKP reluctor wheel damaged, refer to Crankshaft and Bearing Removal in Engine Mechanical 5.7L for crankshaft replacement.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 8

8

Replace the CKP sensor. Refer to Crankshaft Position Sensor Replacement .

Is the action complete?

--

Go to Step 9

--

9

  1. Select the Diagnostic Trouble Code (DTC) option and the Clear DTC option with the scan tool.
  2. Start the engine and idle at the normal operating temperature.
  3. Select the Diagnostic Trouble Code (DTC) option and the Specific DTC option, then enter the DTC number with the scan tool.
  4. Operate vehicle within the Conditions for Running this DTC as specified in the supporting text, if applicable.

Does the scan tool indicate that this test ran and passed?

--

Go to Step 10

Go to Step 2

10

Select the Capture Info option and the Review Info option with the scan tool.

Does the scan tool display any DTCs that you have not diagnosed?

--

Go to the applicable DTC table

System OK