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 works in conjunction with a 58-rib reluctor ring attached to the crankshaft in which two ribs are missing, 60 minus 2 ring. The engine control module (ECM) synchronizes the CKP by the reference gap which is created by the two missing ribs. The CKP sensor circuits connect directly to the ECM. The circuits between the CKP sensor and the ECM consists of the following circuits:

    • A CKP sensor high
    • A CKP sensor low
    • A shielded ground

If the ECM has detected no CKP sensor pulses, DTC P0335 sets.

Conditions for Running the DTC

    • The engine is cranking or running.
    • DTCs P0341, P0342, P0343 are not set.

Conditions for Setting the DTC

The ECM has detected no CKP sensor pulses.

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.

Test Description

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

  1. This step tests for a short to voltage in a CKP sensor circuit between the ECM connector and the CKP connector when the key is off.

  2. This step tests for a short to voltage in a CKP sensor circuit and an ignition circuit between the ECM connector and the CKP connector.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine 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 Step 4

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 Intermittent Conditions

4

  1. Turn OFF the ignition.
  2. Disconnect the crankshaft position (CKP) sensor harness connector.
  3. Measure the voltage between a known good ground and each of the CKP sensor circuits at the controller side of the CKP harness connector.

Is the voltage more than the specified value?

3 V

Go to Step 12

Go to Step 5

5

  1. Turn ON the ignition, with the engine OFF.
  2. Connect the DMM to a known good ground and each of the CKP sensor circuits at the controller side of the CKP harness connector.

Is the voltage more than the specified value?

3 V

Go to Step 12

Go to Step 6

6

Measure the resistance from the high circuit of the CKP sensor and the low circuit of the CKP sensor at the component side of the CKP harness connector with a DMM.

Is the resistance within the specified range?

700-1100 ohms

Go to Step 7

Go to Step 16

7

Measure the resistance from the high circuit of the CKP sensor and the shielded ground circuit of the CKP sensor at the component side of the CKP harness connector with a DMM.

Does the DMM display the specified value?

OL

Go to Step 8

Go to Step 16

8

Measure the resistance from the low circuit of the CKP sensor and the shielded ground circuit of the CKP sensor at the component side of the CKP harness connector with a DMM.

Does the DMM display the specified value?

OL

Go to Step 9

Go to Step 16

9

  1. Connect the CKP sensor connector.
  2. Disconnect the engine control module (ECM) harness connector.
  3. Measure the resistance from the high circuit of the CKP sensor and the low circuit of the CKP sensor with a DMM.

Is the resistance within the specified range?

700-1100 ohms

Go to Step 10

Go to Step 14

10

Measure the resistance from the high circuit of the CKP sensor and the shielded ground circuit of the CKP sensor with a DMM.

Does the DMM display the specified value?

OL

Go to Step 11

Go to Step 15

11

Measure the resistance from the low circuit of the CKP sensor and the shielded ground circuit of the CKP sensor with a DMM.

Does the DMM display the specified value?

OL

Go to Step 20

Go to Step 15

12

  1. Connect the CKP sensor connector.
  2. Disconnect the ECM harness connector.
  3. Measure the voltage between a good ground and each of the CKP sensor circuits at the ECM harness connector.

Is the voltage more than specified value?

3 V

Go to Step 13

Go to Step 20

13

Repair the short to voltage in the affected CKP sensor circuit. Refer to Wiring Repairs and Connector Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 22

--

14

Repair the following conditions in the affected CKP sensor circuit:

    • An open
    • A high resistance
    • Circuits shorted together

Did you complete the repair?

--

Go to Step 22

--

15

Repair the short to ground in the affected CKP sensor circuit. Refer to Wiring Repairs and Connector Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 22

--

16

Inspect for poor connections at the CKP sensor harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 17

17

Important: If the sensor harness is damaged in any way, DO NOT repair the harness.

  1. Remove the CKP sensor. Refer to Crankshaft Position Sensor Replacement and Diagnostic Aids.
  2. Inspect the CKP sensor and its harness for the following conditions:
  3. • Physical damage
    • Excessive play or looseness
    • Improper installation
    • Foreign material pressing between the CKP sensor and the reluctor ring.
    • Electromagnetic interference in the CKP sensor circuits
    • Excessive air gap between the CKP sensor and the reluctor ring

Did you find and correct the condition?

--

Go to Step 22

Go to Step 18

18

Inspect the reluctor ring for the following conditions:

    • Physical damage
    • Improper installation
    • Excessive end play or looseness

Refer to Crankshaft and Bearing Removal in Engine Mechanical.

Did you find and correct the condition?

--

Go to Step 22

Go to Step 19

19

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

Did you complete the replacement?

--

Go to Step 22

--

20

Inspect for poor connections at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

--

Go to Step 22

Go to Step 21

21

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

--

Go to Step 22

--

22

  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 23

23

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