GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The crankshaft position (CKP) sensor signal indicates the crankshaft speed and position. The CKP sensor produces an AC voltage of different amplitude and frequency , depending on the velocity of the crankshaft. The CKP sensor connects to the powertrain control (PCM) module through the following circuits:

    • The CKP sensor 1 signal circuit
    • The low reference circuit

If the PCM detects an incorrect number of CKP pulses, DTC P0336 sets.

Conditions For Running The DTC

    • The engine is running.
    • DTC P0341 is not set.

Conditions for Setting the DTC

The CKP resync counter increments more than 15 times within 4 minutes and 15 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

    • If the complaint was Engine Cranks But Will Not Run, you may set DTC P0336 when attempting to start the engine more than 15 times, and the ignition is not turned OFF between attempts.
    • The following conditions may cause this DTC to set:
       - Crankshaft reluctor wheel damage or improper installation
       - Excessive air gap between the CKP sensor and the reluctor wheel
       - Foreign material passing between the sensor and the reluctor wheel
    • Excess crankshaft end play causes the CKP sensor reluctor wheel to move out of alignment with the CKP sensor. This may result in any one of the following:
       - A no start
       - A start and stall
       - Erratic performance
    • For an intermittent, refer to Intermittent Conditions .

Test Description

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

  1. When a medium resolution resync occurs, an engine stumble should also occur. If the electrical connection of a component or an electrical wire is malfunctioning, an engine stumble or a medium resolution resync may be induced by wiggling the circuit or electrical connector.

  2. Operating malfunctioning non-engine related electronic components may emit electromagnetic interference (EMI), which may cause a resync. This step determines if the medium resolution resyncs are being caused by an outside source.

  3. Thoroughly check any suspected circuitry.

  4. An intermittent problem may be caused by a number of conditions.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

Connect End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Attempt to start the engine.

Does the engine start and run?

--

Go to Step 3

Go to Electronic Ignition (EI) System Diagnosis

3

  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  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.

Does the DTC fail this ignition?

--

Go to Step 4

Go to Step 5

4

Caution:  Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury.

With the engine running, wiggle the electrical connectors of the following components and related circuits, while listening for the engine to stumble:

    • The PCM
    • The CKP

Does the engine stumble?

--

Go to Step 6

Go to Step 7

5

  1. Operate any non-engine related electronic component on the vehicle.
  2. Observe the Med. Resolution Resync Counter parameter with the scan tool.

Does the Med. Resolution Resync Counter parameter increment while operating any non-engine related electronic components?

--

Go to Step 9

Go to Step 4

6

  1. Turn OFF the ignition.
  2. Test for an intermittent and for a poor connection at the connector that caused the engine to stumble. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 14

--

7

Did the MIL illuminate in step 3?

--

Go to Step 8

Go to Diagnostic Aids

8

  1. Turn OFF the ignition.
  2. Inspect the following items for rubbed through wire insulation or for wiring being pinched:
  3. • The PCM
    • The CKP sensor
    • Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 10

9

  1. Turn OFF the ignition.
  2. Repair the circuitry of the malfunctioning or interfering component. Refer to Wiring Repairs in Wiring Systems.
  3. Move any wiring that is causing the interference away from the CKP wiring harness.

Did you complete the repair?

--

Go to Step 14

--

10

  1. Remove the CKP sensor. Refer to Crankshaft Position Sensor Replacement .
  2. Visually inspect the CKP sensor for the following conditions:
  3. • Any physical damage
    • A loose or improper installation
    • Any wiring routed too closely to the secondary ignition components

Did you find and correct the condition?

--

Go to Step 14

Go to Step 11

11

Visually inspect the CKP reluctor wheel for damage or looseness. Refer to Diagnostic Aids in this DTC and Crankshaft and Bearing Cleaning and Inspection in Engine Mechanical.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 12

12

  1. Replace the CKP sensor. Refer to Crankshaft Position Sensor Replacement .
  2. Idle the engine for the specified minutes or until the malfunction indicator lamp (MIL) turns ON.

Did the MIL illuminate?

5 Minutes

Go to Step 13

Go to Step 14

13

  1. Replace the PCM. Refer to Powertrain Control Module Replacement .
  2. Idle the engine for the specified minutes or until the MIL turns ON.

Did the MIL illuminate?

5 Minutes

Go to Diagnostic Aids

Go to Step 14

14

  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC.

Did the DTC fail this ignition?

--

Go to Step 2

Go to Step 15

15

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK