GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The DTC P0339 Crankshaft Position (CKP) Sensor Circuit Intermittent diagnostic the verifies that the signal from the CKP sensor is continuous. The CKP sensor is a magnetic generator type sensor, producing an alternating current signal. The CKP sensor signal increases in both frequency and amplitude as the engine RPM increases. The CKP sensor sends this reference signal to the powertrain control module (PCM) to indicate the crankshaft RPM and position. This reference signal is used by the PCM to calculate fuel injection pulse, establish top dead center (TDC) for ignition timing and where to start ignition coil and injection sequencing. There will be no spark or fuel delivery if there is no CKP sensor signal.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0339 Crankshaft Position (CKP) Sensor Circuit Intermittent

Conditions for Running the DTC

    • The engine speed is more than 600 RPM.
    • DTC P0339 runs continuously once the above condition has been met.

Conditions for Setting the DTC

The crankshaft position sensor signal to the PCM is not continuous.

Action Taken When the DTC Sets

    • The PCM illuminates the malfunction indicator lamp (MIL) during the second key cycle in which the DTC sets.
    • The PCM stores the conditions which were present when the DTC set as Freeze Frame data.

Conditions for Clearing the MIL/DTC

    • The PCM turns OFF the MIL on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.
    • A DTC will clear after 40 consecutive warm-up cycles have occurred without a fault.
    • A DTC can be cleared by using the scan tool Clear DTC Information function.

Diagnostic Aids

    • Check for any of the following conditions:
       - Check the CKP sensor output signal with a scan tool. The scan tool will display engine speed while cranking when the PCM detects the CKP sensor signal. Observe the Engine Speed parameter while cranking the engine. The scan tool should indicate a steady 200-300 RPM while cranking.
       - The CKP sensor performance may be affected by temperature. Check the sensors operation and internal resistance at various temperatures. The CKP sensor resistance when cold should be between 1,630 ohms and 2,740 ohms at -10 to +50°C (+14 to +122°F). The CKP sensor resistance when hot should be between 2,065 ohms and 3,225 ohms at 50-100°C (122-212°F).
       - An intermittent DTC P0339 can be caused by a defective signal rotor. Remove the CKP sensor and visually inspect the teeth of the signal rotor through the CKP sensor aperture for damage, foreign material, or incorrect installation.
       - A DTC P0339 that sets while driving and checks OK may be caused by inadequate CKP sensor circuit shielding. Check that the CKP sensor circuit is properly shielded and that the drain wire is fastened securely to ground.
    • An intermittent malfunction may be caused by a fault in the CKP sensor electrical circuit. Inspect the wiring harness and the components for an intermittent condition. Refer to Intermittent Conditions .
    • Repair any electrical circuit faults that were found. Refer to Wiring Repairs .
    • The information included in the Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC first set.

Test Description

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

  1. The Diagnostic System Check - Vehicle prompts the technician to complete some basic checks and store the Freeze Frame data on the scan tool, if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

  2. This step determines whether the DTC P0339 is the result of a hard failure or an intermittent condition. If engine will not start, crank the engine over 3 consecutive ignition cycles (key ON/key OFF).

  3. This step verifies the internal resistance of the crankshaft position sensor. A typical value at 23°C (74°F) is 2.1K ohms.

  4. This step tests the CKP sensor output signal and electrical circuit to the PCM.

  5. This step determines which half of the CKP sensor circuit is faulty.

  6. This step inspects for a faulty signal rotor. Visually inspect the teeth of the signal rotor through the CKP sensor aperture for damage, foreign material, and mis-alignment.

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?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Are DTCs P0339 and P0340 both set?

--

Go to Step 10

Go to Step 3

3

Does the vehicle start and run?

--

Go to Step 4

Go to Step 5

4

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Save the DTC and Freeze Frame information into the scan tool memory.
  4. Perform the scan tool Clear DTC Information function.
  5. Operate the vehicle within the Freeze Frame conditions, as specified.

Is DTC P0339 set?

--

Go to Step 5

Go to Diagnostic Aids

5

  1. Turn OFF the ignition.
  2. Disconnect the crankshaft position (CKP) sensor electrical connector.
  3. Measure the resistance of the CKP sensor with a DMM.

Is the resistance within the appropriate specified range?

1,630-2,740 ohms at -10 to +50°C (+14 to +122°F) or 2,065-3,225 ohms at 50-100°C (122-212°F)

Go to Step 6

Go to Step 13

6

  1. Connect the CKP sensor electrical connector.
  2. Disconnect the powertrain control module (PCM) electrical connector C1.
  3. Connect the DMM to CKP Input circuit and the Sensor Ground circuit on the harness side of the PCM connector.
  4. Observe the AC voltage while cranking the engine.

Was the AC voltage indicated while cranking within the specified range?

1.4-1.6 V AC

Go to Step 14

Go to Step 7

7

  1. Connect the DMM to CKP Input circuit and a known good ground.
  2. Observe the AC voltage while cranking the engine.

Was the AC voltage indicated while cranking within the specified range?

1.4-1.6 V AC

Go to Step 9

Go to Step 8

8

Test for an open or a short in the CKP sensor input circuit. Refer to Wiring Repairs .

Did you find and repair a condition?

--

Go to Step 15

Go to Step 11

9

Repair the open in the CKP sensor ground circuit. Refer to Wiring Repairs .

Did you complete the repair?

--

Go to Step 15

--

10

  1. Test for an open in the CKP and the CMP sensor ground circuit between SP108 and the PCM.
  2. Repair as necessary. Refer to Wiring Repairs .

Did you find and correct a condition?

--

Go to Step 15

Go to Step 14

11

  1. Remove the CKP sensor. Refer to Crankshaft Position Sensor Replacement .
  2. Visually inspect the CKP sensor signal rotor for the following conditions:
  3. • Any damaged teeth
    • Any foreign material
    • The correct installation
  4. Repair as necessary.

Did you find and correct a condition?

--

Go to Step 15

Go to Step 12

12

  1. Test for an intermittent or a poor electrical connection at the CKP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
  2. Repair as necessary.

Did you find and correct a condition?

--

Go to Step 15

Go to Step 13

13

Replace the crankshaft position sensor. Refer to Crankshaft Position Sensor Replacement .

Did you complete the replacement?

--

Go to Step 15

--

14

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

Did you complete the replacement?

--

Go to Step 15

--

15

  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 16

Go to Step 2

16

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 - Vehicle

System OK