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 ignition control (IC) module. The circuits between the CKP sensor and the IC module consist of the following circuits:

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

Conditions For Running The DTC

    • Diagnostic trouble code (DTC) P0341 is not set.
    • The engine is running.

Conditions for Setting the DTC

The CKP resync counter goes 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 a DTC P0336 when attempting to start the engine more than 15 times and the ignition is not turned OFF between attempts.
    • An intermittent problem may be caused by the following conditions:
       - Rubbed-through wire insulation
       - Poor electrical connections
       - Broken wire inside the insulation
    • Thoroughly check any suspected circuitry for the following conditions:
       - Backed-out terminals
       - Improper mating
       - Broken locks
       - Improperly formed terminals
       - Damaged terminals
       - Poor terminal-to-wire connections
       - Physical damage to the wiring harness
    • An intermittent can also be the result of a defective reluctor wheel. Remove the CKP sensor and inspect the reluctor wheel through the hole. Refer to Crankshaft Position Sensor Replacement .

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 inspect any suspected circuitry. Refer to Diagnostic Aids.

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

Step

Action

Value(s)

Yes

No

Schematic Reference: Engine Controls Schematics

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.

Will the engine start?

--

Go to Step 3

Go to Engine Cranks but Does Not Run

3

  1. Observe the Freeze Frame/Failure Records data 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 as specified in the supporting text or as close to the Freeze Frame/Failure Records data that you observed.

Does the DTC fail this ignition?

--

Go to Step 4

Go to Step 5

4

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

    • The PCM
    • The ignition control module (ICM)
    • 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 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. Inspect for a poor electrical terminal connection or replace the terminal in the circuit which caused the engine to stumble.
  3. Repair the electrical connection or the terminal in the circuit as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 13

--

7

Did the MIL illuminate in step 3?

--

Go to Step 8

Go to Step 13

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 ICM
    • The CKP sensor
  4. Repair the wiring as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 13

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 13

--

10

  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

Go to Step 11

Go to Step 13

11

  1. Turn OFF the ignition.
  2. Replace the ICM. Refer to Ignition Control Module Replacement .
  3. Start the engine.
  4. Idle the engine for the specified minutes or until the MIL turns ON.

Did the MIL illuminate?

5

Go to Step 12

Go to Step 13

12

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

Did the MIL illuminate?

5

Go to Diagnostic Aids

Go to Step 13

13

  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC run and pass?

--

Go to Step 14

Go to step 2

14

With a scan tool, observe the stored information, Capture Info.

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

--

Go to Diagnostic Trouble Code (DTC) List

System OK