GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2004 🢒 CTS 🢒 Engine 🢒 Engine Controls - 2.6L and 3.2L 🢒 DTC P0338

Circuit Description

The crankshaft position (CKP) sensor signal indicates the crankshaft speed and position. The CKP sensor works in conjunction with a 58-rib reluctor ring attached to the crankshaft in which two ribs are missing, 60 minus 2 ring. The engine control module (ECM) synchronizes the crankshaft position by the reference gap which is created by the two missing ribs. The CKP sensor circuits are connected directly to the ECM. The circuits between the CKP sensor and the ECM consists of the following circuits:

    • A CKP sensor high
    • A CKP sensor low
    • A shielded ground

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

Conditions for Running the DTC
    • The engine is cranking or running.
    • DTCs P0341, P0342, P0343 are not set.

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 resistance of the CKP sensor and its lead.

    2.

  2. This step inspects for electromagnetic interference in any of the CKP circuits.

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.

Does the DTC fail this ignition?

--

Go to Step 4

Go to Intermittent Conditions

4

  1. Disconnect the crankshaft position (CKP) sensor harness connector.
  2. Measure the resistance from the high circuit of the CKP sensor and the low circuit of the CKP sensor with a DMM.

Is the resistance within the specified range?

700-1100 ohms

Go to Step 5

Go to Step 8

5

Inspect all of the circuits going to the CKP sensor for the following:

    • Routed too closely to other wiring or components
    • Routed too closely to after-market add- on electrical equipment
    • Routed too closely to solenoids, relays, and motors

Did you find and correct the condition?

--

Go to Step 12

Go to Step 6

6

Inspect for poor connections at the CKP sensor harness connector. 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 12

Go to Step 7

7

Inspect for poor connections 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 12

Go to Step 11

8

Important: If the sensor lead is damaged in any way, DO NOT repair the lead.

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

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

9

Inspect the reluctor ring for the following conditions:

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

Refer to Crankshaft and Bearing Removal in Engine Mechanical.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 10

10

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

Did you complete the replacement?

--

Go to Step 12

--

11

Replace the ECM. Refer to Engine Control Module Replacement .

Did you find and correct the condition?

--

Go to Step 12

--

12
  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 13

13

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