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 crankshaft position variation is not within the CKP system variation compensating values stored in the ECM, DTC P0300 may set. If the ECM detects that the CKP system variation values are not stored in the ECM memory, DTC P0315 sets.
This diagnostic procedure supports the following DTC:
DTC P0315 Crankshaft Position (CKP) System Variation Not Learned
• | DTCs P0336, P0340, P0341 are not set. |
• | DTC P0315 runs once per ignition cycle once the above condition is met. |
• | The CKP system variation values are not stored in the ECM memory. |
• | The above condition is met for 0.5 second. |
• | 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. |
• | 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. |
Step | Action | Yes | No | ||||||||||||||||
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Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module Connector End Views | |||||||||||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |||||||||||||||||
2 |
Important: The Crankshaft Position (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 . Does the scan tool display Learned This Ignition? | Go to Step 4 | Go to Step 3 | ||||||||||||||||
3 | If the CKP system variation learn procedure cannot be performed successfully, inspect for the following conditions:
Did you find and correct the condition? | Go to Step 4 | -- | ||||||||||||||||
4 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 5 | ||||||||||||||||
5 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | System OK |