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 is connected directly to the powertrain control module (PCM). The circuits between the CKP sensor and the PCM consist of 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.
    • DTCs P0340, P0341 are 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

    • The following conditions may cause this DTC to set:
       - The crankshaft reluctor wheel is damaged or is improperly installed.
       - The sensor is coming in contact with the reluctor wheel.
       - If the crankshaft rotates backwards, this DTC sets. This condition can occur 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 of the following conditions:
       - A no start
       - A start and stall
       - Erratic performance
    • An improperly installed crankshaft could cause excess crankshaft end play.
    • 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. Refer to Diagnostic Aids.

  4. An intermittent problem may be caused by a number of conditions. Refer to Diagnostic Aids.

  5. Program the replacement PCM and perform the Crankshaft Position System Variation Learn Procedure.

Step

Action

Value(s)

Yes

No

Schematic Reference: Engine Controls Schematics

Connector 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 Engine Cranks but Does Not Run

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.

Did the DTC fail this ignition?

--

Go to Step 4

Go to Step 5

4

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

    • The powertrain control module (PCM)
    • The crankshaft position sensor (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 with the scan tool.

Does the Med. Resolution Resync Counter on the scan tool 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 a poor connection 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 Step 14

8

  1. Turn OFF the ignition.
  2. Inspect the following circuits 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 and the ICM wiring harness.

Did you complete the repair?

--

Go to Step 14

--

10

  1. Remove the CKP sensor.
  2. Visually inspect the CKP sensor for the following conditions:
  3. • Any physical damage
    • Loose or improper installation
    • Any wiring routed too closely to secondary ignition components

Did you find and correct the condition?

--

Go to Step 11

Go to Step 14

11

Visually inspect the CKP reluctor wheel for damage or looseness. Refer to Diagnostic Aids 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. Start the engine.

Did the MIL Illuminate?

--

Go to Step 13

Go to Step 14

13

  1. Turn OFF the ignition.
  2. Replace the PCM. Refer to Powertrain Control Module Replacement .

Did the MIL illuminate?

--

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. You may also operate the vehicle within the conditions that you observed from the Freeze frame/Failure Records.

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