GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2002 🢒 VUE - FWD 🢒 Engine 🢒 Engine Controls - 3.0L (L81) 🢒 DTC P0338

Object Number: 1254429 Size: MF
Engine Controls Component Views
Engine Controls Schematics

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 battery voltage. The engine control module (ECM) uses a pull-up voltage of 2.5 volts on each CKP sensor circuit for reduction of noise interference from electromagnetic generating devices. The CKP sensor works in conjunction with a 58-tooth reluctor wheel on the crankshaft. The CKP sensor connects to the ECM through the following circuits:

    • A CKP sensor high circuit
    • A CKP sensor low circuit

If the ECM detects more than 58 reference pulses, DTC P0338 sets.

Conditions for Running the DTC

DTCs P0341, P0342, P0343 are not set.

The engine is cranking or running

Conditions for Setting the DTC

The ECM has detected more than 58 reference 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 an internally shorted sensor.

    2.

  2. This step tests for a short to voltage in the battery circuit.

    3.

  3. This step tests for a short to voltage in the battery circuit.

    4.

  4. This step tests for a short to voltage in the ignition circuit.

    5.

  5. This step tests for a short to voltage in the ignition circuit.

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.

Did the DTC fail this ignition?

--

Go to Step 4

Go to Intermittent Conditions

4

Inspect the harness of the crankshaft position (CKP) sensor for incorrect routing that is too close to the following components:

    • The secondary ignition wires or module
    • The battery cables
    • Any solenoids
    • Any relays
    • Any motors
    • After-market add-on electrical equipment

Did you find and correct the condition?

--

Go to Step 18

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
  3. Disconnect the CKP sensor.
  4. Measure the resistance from the high circuit to the low circuit of the CKP sensor with a DMM. Refer to Circuit Testing in Wiring Systems.

Is the resistance within the specified range?

800-1200 ohms

Go to Step 6

Go to Step 14

6

Measure the voltage from the high circuit of the CKP sensor harness connector to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems.

Is the voltage more than the specified value?

4 V

Go to Step 10

Go to Step 7

7

Measure the voltage from the low circuit of the CKP sensor harness connector to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems.

Is the voltage more than the specified range?

4 V

Go to Step 11

Go to Step 8

8

  1. Turn On the ignition, with the engine OFF.
  2. Measure the voltage from the high circuit of the CKP sensor harness connector to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems.

Is the voltage more than the specified value?

4 V

Go to Step 10

Go to Step 9

9

Measure the voltage from the low circuit of the CKP sensor harness connector to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems.

Is the voltage more than the specified value?

4 V

Go to Step 11

Go to Step 12

10

Test the CKP sensor high circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 18

Go to Step 12

11

Test the CKP sensor low circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 18

Go to Step 12

12

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 18

Go to Step 13

13

Test for an intermittent and for a poor connection at the engine control module (ECM). 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 18

Go to Step 17

14
  1. Remove the CKP sensor. Refer to Crankshaft Position Sensor Replacement .
  2. 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 18

Go to Step 15

15

Inspect the 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 18

Go to Step 16

16

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

Did you complete the replacement?

--

Go to Step 18

--

17

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

--

Go to Step 18

--

18

Clear the DTCs with a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine.

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 19

19

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