GM Service Manual Online
For 1990-2009 cars only

Object Number: 46122  Size: MF
Handling ESD Sensitive Parts Notice
Engine Controls Components 5.0L/5.7L/7.4L
Engine Controls Schematics
OBD II Symbol Description Notice

Circuit Description

The Crankshaft Position (CKP) sensor sends a reference signal to the Vehicle Control Module (VCM) in order to indicate the crankshaft position and RPM. The VCM uses this information in order to determine when to pulse the ignition coil, the fuel injectors and the control ignition timing. The DTC P0339 is a type B DTC.

Conditions for Setting the DTC

The following conditions will set the DTC:

  1. The MAF sensor is at least 5 g/s.
  2. The change in the calculated engine speed is at least 1000 RPM.

Action Taken When the DTC Sets

The VCM will turn ON the MIL after 2 consecutive driving cycles with the fault active.

Conditions for Clearing the MIL/DTC

A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (the coolant temperature has risen 40°F from the start-up coolant temperature and the engine coolant temperature exceeds 160°F during that same ignition cycle) or the scan tool clearing feature has been used.

Diagnostic Aids

A poor connection, a rubbed through wire insulation, or a wire that is broken inside the insulation may cause an intermittent problem.

Thoroughly check any circuitry, that is suspected of causing the intermittent complaint for the following conditions:

    • Backed out terminals
    • Improper mating
    • Broken locks
    • Improperly formed or damaged terminals
    • Poor terminal to wiring connections
    • Physical damage to the wiring harness

Inspect the face of the CKP sensor for metal shavings. This could result in an intermittent DTC P0339

Refer to Important Preliminary Checks .

Test Description

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

  1. Checks the ignition feed circuit to the Crankshaft Position sensor

  2. Checks the duty cycle of the Crankshaft Position sensor

Step

Action

Value(s)

Yes

No

1

Important: Before clearing DTCs, use the scan tool in order to record the freeze frame and failure records for reference because using the Clear Info function will lose the data.

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Does the vehicle start and continue to run?

--

Go to Diagnostic Aids

Go to Step 3

3

  1. Disconnect the Crankshaft Position (CKP) sensor.
  2. Connect a test lamp to ground.
  3. Turn the ignition ON leaving the engine off.
  4. Probe the Crankshaft Position sensor ignition feed circuit at the engine side of the harness connector.

Is the test lamp on?

--

Go to Step 4

Go to Step 6

4

Connect the test lamp between the CKP sensor ignition feed and the CKP sensor Low circuit.

Is the test lamp on?

--

Go to Step 5

Go to Step 7

5

  1. Turn the ignition off.
  2. Install the gray jumpers from the Connector Tester Kit J 35616 between the engine harness connector and the CKP sensor.
  3. Install a DVM set to the Duty Cycle position, between the CKP sensor (4X) signal circuit and the CKP sensor Low circuit.
  4. Crank the engine.

Is the duty cycle within the specified range?

40%-60%

Go to Step 8

Go to Step 10

6

Repair the open or short to ground in the CKP sensor ignition feed circuit. Refer to Wiring Repairs in Engine Electrical.

Is the action complete?

--

Go to Step 13

--

7

Check the CKP sensor Low circuit for an open.

Was a problem found?

--

Go to Step 11

Go to Step 9

8

  1. With the DVM still connected between the CKP sensor (4X) signal circuit and the CKP sensor Low circuit, select the AC volt scale on the DVM.
  2. Crank the engine.

Is the voltage above the specified value?

10.0 V

Go to Step 11

Go to Step 9

9

Check for an open in the CKP sensor (4X) signal circuit or an open in the CKP sensor Low circuit.

Was a problem found?

--

Go to Step 11

Go to Step 12

10

Notice: In order to avoid damaging the replacement three-way catalytic converter, correct the engine misfire or mechanical fault before replacing the three-way catalytic converter.

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

Is the action complete?

--

Go to Step 13

--

11

Repair as necessary.

Is the action complete?

--

Go to Step 13

--

12

Replace the VCM.

Important: If the VCM is faulty, reprogram the VCM. Refer to VCM Replacement/Programming (With KS Calibration PROM) .

Is the action complete?

--

Go to Step 13

--

13

  1. Using the scan tool, select the DTC and the Clear Info.
  2. Start the engine.
  3. Idle at the normal operating temperature.
  4. Select the DTC and the Specific.
  5. Enter the DTC number which was set.
  6. Operate the vehicle within the conditions for setting this DTC as specified in the supporting text.

Does the scan tool indicate that this diagnostic ran and passed?

--

Go to Step 14

Go to Step 2

14

Using the scan tool, select the Capture Info and the Review Info.

Are any DTCs displayed that have not been diagnosed?

--

Go to The Applicable DTC Table

System OK