Circuit Description
Important: The engine control module (ECM) continuously learns the crankshaft position (CKP) system variations. A CKP variation learn procedure cannot be performed with a scan tool.
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 reluctor wheel. 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 continuously learns the CKP system variation values. If the actual CKP variation is not within the CKP system variation compensating values stored in the ECM, this DTC sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1320 Crankshaft Position (CKP) System Variation Not Learned
Conditions for Running the DTC
| • | The engine speed is running. |
| • | DTC P1320 runs continuously once the above condition is met. |
Conditions for Setting the DTC
| • | The ECM detects an incorrect CKP system variation values. |
| • | The above condition is detected on decelerations or when a fuel cut-off occurs. |
Action Taken When the DTC Sets
| • | The malfunction indicator lamp (MIL) will illuminate after 3 consecutive trips with a fail. |
| • | The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers. |
Conditions for Clearing the MIL/DTC
| • | The MIL will turn OFF after 4 consecutive ignition cycles in which the diagnostic runs without a fault. |
| • | DTCs can be cleared by using the scan tool. |
| • | Disconnect the ECM battery feed for more than 10 seconds. |
Step | Action | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Engine Controls? | Go to Step 2 | |||||||||
2 |
Did DTC P1320 fail this ignition? | Go to Step 4 | Go to Step 3 | ||||||||
3 |
Did the DTC fail this ignition? | Go to Step 4 | Go to Intermittent Conditions | ||||||||
4 |
Is DTC P0335, P0336, or P0337 also set? | Go to Step 5 | |||||||||
5 |
Important: If the reluctor wheel is damaged, replace the CKP sensor and the crankshaft. Refer to Crankshaft Position Sensor Replacement . Turn OFF the ignition. Inspect the reluctor wheel, crankshaft, and the CKP sensor for the following conditions:
Did you complete the inspection? | Go to Step 6 | -- | ||||||||
6 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 7 | ||||||||
7 | Are there any DTCs that have not been diagnosed? | System OK |
