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.

DIAGNOSTIC AIDS
- The following conditions may cause this DTC to set:
- The CKP shielded wiring for continuity or damage-By disconnecting the CKP sensor connector the shielded ground can be tested for continuity back to the ECM by connecting a test lamp to B+. Good CKP shield continuity will illuminate the test lamp.
- Excessive air gap between the CKP sensor and the reluctor ring
- CKP sensor damage or improper installation
- Crankshaft reluctor ring damage or improper installation
- Foreign material passing between the CKP sensor and the reluctor ring
- Poor connection or poor terminal tension at the CKP sensor or the ECM-Refer to Diagnostic Aids for Circuit Testing and Wiring Repair Procedures.
- Excess crankshaft end play causes the reluctor ring to move out of alignment with the CKP sensor. This could result in any one of the following conditions:
- A no start
- A start and stall
- Erratic performance
- For an intermittent, refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION

Steps 1-3:

Steps 4-7:

Steps 8-13:

The numbers below refer to the step numbers on the diagnostic table.
4. This step tests for resistance of the CKP sensor and its lead.
5. This step inspects for electromagnetic interference in any of the CKP circuits.