Diagnostic Instructions
DTC Descriptor
DTC P0315: Crankshaft Position (CKP) System Variation Not Learned
Circuit/System 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 engine control module (ECM) to accurately
compensate for reference period variations. This enhances the ability of the ECM to detect misfire events over a wider range of engine speed and load. The ECM stores the CKP system variation values after a learn procedure has been performed. If the actual CKP
variation is not within the CKP system variation compensating values stored in the ECM, DTC P0300 may set.
Conditions for Running the DTC
| • | DTC P0315 runs continuously when the above condition is met. |
Conditions for Setting the DTC
The CKP system variation values are not stored in the ECM 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
| • | 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. |
Reference Information
Scan Tool Reference
Circuit/System Testing
Important: The CKP System Variation Learn Procedure may have to be repeated up to 5 times before the procedure is learned for various reasons.
Perform the CKP System Variation Learn Procedure. Refer to
Crankshaft Position System Variation Learn
. The scan tool should display Learned this Ignition.
| ⇒ | If the CKP System Variation Learn Procedure cannot be performed successfully, inspect for the following conditions: |
| • | Any worn crankshaft main bearings |
| • | A damaged reluctor wheel |
| • | Excessive crankshaft runout |
| • | Interference in the signal circuit of the CKP sensor |
| • | The ignition switch is in the ON position until the battery is drained. |
| • | An ECM power disconnect with the ignition ON that may have erased the stored value and set DTC P0315 |
| • | Any debris between the CKP sensor and the reluctor wheel |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
