GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The crankshaft position (CKP) sensor is a variable reluctance sensor. The CKP sensor signal indicates the crankshaft speed and position. The CKP sensor produces an AC voltage of different amplitude and frequency. The frequency depends on the velocity of the crankshaft, and the AC voltage output depends on the crankshaft position and battery voltage. The CKP sensor works in conjunction with a 58X reluctor wheel attached to the crankshaft. The CKP sensor is also used to detect misfire and for tachometer display. The CKP sensor connects directly to the powertrain control module (PCM) through the following circuits:

    • The CKP sensor signal
    • The low reference

If the PCM detects an incorrect number of pulses from the CKP sensor, DTC P0335 sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0335 Crankshaft Position (CKP) Sensor Circuit

Conditions for Running the DTC

    • The engine is cranking or running.
    • A CMP sensor signal is present
    • DTC P0335 runs continuously once the above conditions are met.

Conditions for Setting the DTC

    • The PCM detects an incorrect number of CKP pulses during engine cranking for 4 seconds.
    • The PCM detects an incorrect number of CKP pulses while the engine is running for 2 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.

Step

Action

Values

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 - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Start the engine.
  2. Observe the Engine Speed parameter on the scan tool.

Does the Engine Speed parameter increment?

--

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 powertrain control module (PCM) connector.
  3. Measure the resistance from the crankshaft position (CKP) sensor signal circuit to the low reference circuit of the CKP sensor with a DMM.

Is the resistance within the specified range?

1,360-1,730 ohms

Go to Step 5

Go to Step 6

5

Test the CKP sensor circuits for a short to voltage or a short to ground. Refer to Circuit Testing .

Did you find and correct the condition?

--

Go to Step 14

Go to Step 9

6

Test the CKP sensor circuits for the following conditions:

    • An open
    • A short across circuits
    • A high resistance

Refer to Circuit Testing .

Did you find and correct the condition?

--

Go to Step 14

Go to Step 7

7

Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 14

Go to Step 8

8

Test for an intermittent and for a poor connection at the CKP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 14

Go to Step 10

9

Test for shorted terminals and poor connections at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs

Did you find and correct the condition?

--

Go to Step 14

Go to Step 13

10

  1. Remove the CKP sensor. Refer to Crankshaft Position Sensor Replacement .
  2. Visually inspect the CKP sensor for the following conditions:
  3. • Foreign material passing between the CKP sensor and the reluctor wheel
    • Physical damage
    • Improper installation
    • Electromagnetic interference in the CKP sensor circuits

Did you find and correct the conditions?

--

Go to Step 14

Go to Step 11

11

Visually inspect the CKP reluctor wheel for the following conditions:

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

Refer to Crankshaft and Bearing Cleaning and Inspection .

Did you find and correct the condition?

--

Go to Step 14

Go to Step 12

12

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

Did you complete the replacement?

--

Go to Step 14

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13

Replace the PCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 14

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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 - Vehicle

System OK