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 CKP system variation compensating values are stored in ECM memory after a learn procedure has been performed and the ignition switch is turned to the OFF position for at least 30 seconds. If the actual CKP variation is not within the CKP system
variation compensating values stored in the ECM, DTC P0300 may set.
If the CKP system variation values are not stored in the ECM memory or a proper ECM power down does not occur after completing the CKP Learn Procedure, DTC P0315 sets.
Conditions for Running the DTC
The diagnostic runs continuously.
Conditions for Setting the DTC
The ECM detects that the CKP system variation values are not stored in memory.
Action Taken When the DTC Sets
DTC P0315 is a Type A DTC.
Conditions for Clearing the MIL/DTC
DTC P0315 is a Type A DTC.
Reference Information
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
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 successful.
- Perform the
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:
• | Worn crankshaft main bearings |
• | A damaged or misaligned reluctor wheel |
• | Excessive crankshaft runout |
• | Interference in the signal circuit of the CKP sensor |
• | The ignition switch is in the ON position until there is insufficient system voltage. |
• | An ECM power disconnect with the ignition ON that may have erased the CKP system variation values and set DTC P0315 |
• | Debris between the CKP sensor and the reluctor wheel |
⇒ | If the control module is unable to complete the learn procedure, replace the control module. |
Repair Instructions
Perform the
Diagnostic Repair Verification
prior to using this diagnostic procedure.
Control Module References
for ECM replacement, setup, and programming