GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The crankshaft position (CKP) sensor is a variable reluctance sensor. The CKP sensor 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. The AC voltage output depends on the crankshaft position and the battery voltage. The CKP sensor works in conjunction with a 7X reluctor wheel attached to the crankshaft. The CKP sensor connects to the powertrain control module (PCM) through the following circuits:

    • The CKP sensor signal
    • The low reference

If the PCM detects no pulses from the CKP sensor, DTC P0335 sets.

Conditions for Running the DTC

The engine is cranking or running.

Conditions for Setting the DTC

The PCM detects no pulses from the CKP sensor.

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 number below refers to the step number on the diagnostic table.

  1. When the PCM enables starter operation, the PCM also initiates the diagnostic test routines for the CKP and camshaft position (CMP) sensors. If the ignition switch is in the start position for more than 4 seconds without the engine cranking, the CKP diagnostics may fail and set this DTC.

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-Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Attempt to crank the engine.

Does the engine crank?

--

Go to Step 3

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

3

Attempt to start the engine.

Does the engine start and run?

--

Go to Step 4

Go to Step 5

4

  1. Turn OFF the ignition.
  2. Disconnect the powertrain control module (PCM).
  3. Measure the resistance between the signal circuit and the low reference circuit of the crankshaft position (CKP) sensor with a DMM. Refer to Circuit Testing in Wiring Systems.

Is the resistance within the specified range?

500-900 ohms

Go to Intermittent Conditions

Go to Step 12

5

  1. Crank the engine.
  2. Observe the CKP Active Counter parameter with a scan tool.

Does the CKP Active Counter increment?

--

Go to Step 13

Go to Step 6

6

Test the signal circuit for the following conditions:

    • A short to voltage
    • An open
    • High resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 7

7

Test the low reference circuit for the following conditions:

    • A short to voltage
    • An open
    • High resistance
    • The CKP sensor circuits shorted together

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

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 PCM. 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 14

Go to Step 9

9

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 in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 10

10

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

Did you find and correct the condition?

--

Go to Step 14

Go to Step 11

11

Inspect the CKP reluctor wheel for the following conditions:

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

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

Did you complete the replacement?

--

Go to Step 14

--

13

Replace the PCM. Refer to Powertrain Control Module Replacement

Did you complete the replacement?

--

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 - Vehicle in Vehicle DTC Information

System OK