Circuit Description
The crankshaft position system variation learning feature is used to calculate reference period errors caused by slight tolerance variations in the crankshaft, and the crankshaft position sensors. The calculated error allows the PCM to accurately compensate for reference period varations. This enhances the ability of the PCM to detect misfire events over a wider range of engine speed and load.
The PCM stores the crankshaft position system variation values after a learn procedure has been performed. DTC 1336 set indicates that the crankshaft position system variation values have not been stored in the PCM and the crankshaft position system variation learn procedure must be performed. The learn procedure is required after the following service procedures have been performed, regardless of whether or not DTC P1336 is set:
| • | PCM replacement. |
| • | PCM reprogramming. |
| • | Engine replacement. |
| • | Crankshaft replacement. |
| • | Crankshaft position sensor replacement. |
| • | Any engine repair that disturbs crankshaft to crankshaft position sensor relationship. |
Conditions for Running the DTC
| • | CMP sensor, or CKP sensor DTCs are not set. |
| • | The engine coolant temperature is more than 70°C (158°F). |
Conditions for Setting the DTC
The crankshaft position system variation values are not stored in the PCM memory.
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) the first time the malfunction is detected. |
| • | The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the MIL OFF after the third consecutive trip in which the diagnostic runs and passes. |
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using the scan tool Clear DTC Information function. |
Diagnostic Aids
The crankshaft position system variation compensating values are stored in PCM memory after a learn procedure has been performed. If the actual crankshaft position variation is not within the crankshaft position system variation compensating values stored in the PCM, DTC P0300 may set (refer to Diagnostic Aids for DTC P0300).
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | ||
2 | Perform the crankshaft position system variation learn procedure. Refer to Crankshaft Position System Variation Learn . Is the action complete? | -- | System OK | -- |
