P0315

CIRCUIT DESCRIPTION
The crankshaft position (CKP) system variation learn feature is used to calculate reference period errors caused by slight tolerance variations in the crankshaft, and the CKP sensor. The calculated error allows the powertrain control module (PCM) to accurately compensate for reference period variations. This enhances the ability of the PCM to detect misfire events over a wide range of engine speed and load. If the CKP system variation values are not stored in the PCM memory, DTC P0315 sets.

CONDITIONS FOR RUNNING THE DTC
DTCs P0335, P0336, P0341, P0342, or P0343 are not set.

CONDITIONS FOR SETTING THE DTC
The CKP system variation values are not stored in the PCM memory.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
- 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 CKP system variation values are not stored in the PCM memory after a learn procedure has been performed. If the actual CKP variation is not within the CKP system variation compensating values stored in the PCM, DTC P0300 may set.

The CKP system variation learn procedure is also required when the following service procedures have been performed, regardless of whether DTC P0315 is set.
- An engine replacement
- A PCM replacement
- A harmonic balancer replacement
- A crankshaft replacement
- Any engine repairs which disturb the CKP sensor relationship

If the CKP system variation learn procedure cannot be performed successfully, check for the following conditions and correct as necessary:
- A damaged reluctor wheel
- Excessive crankshaft runout
- A damaged crankshaft
- Interference in the signal circuit of the CKP sensor
- A coolant temperature that is not within the Conditions For Running the DTC
- The ignition switch is in the ON position until the battery is drained
- A PCM power disconnect with the ignition ON may erase the stored value and set the DTC P0315

TEST

Steps 1-4: