Circuit Description
The crankshaft position system variation learning feature calculates
the reference period errors that are caused by slight tolerance variations
in the crankshaft, the crankshaft balancer interrupter rings,
and the crankshaft position sensor hall effect switches. The calculated
error allows the PCM to accurately compensate for reference period
variations. This enhances the ability of the PCM to detect misfire
events during a wider range of engine speed and load conditions.
The crankshaft position system variation values are stored in the PCM
non-volatile memory after a learn procedure has been performed. If the crankshaft
position system variation values are not stored in the PCM, DTC P1336
will set. The learn procedure is required after the following
service procedures have been performed:
| • | Crankshaft balancer replacement |
| • | Crankshaft position sensor replacement |
| • | Any engine repair which disturbs the crankshaft or the harmonic
balancer to crankshaft position sensor relationship. |
Conditions for Running the DTC
| • | No CMP or CKP sensor DTCs are 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) during
the first trip in which the diagnostic test has been run and failed. |
| • | The PCM will store conditions which were present when the DTC
set as Freeze Frame and Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the malfunction indicator lamp (MIL) during
the third consecutive trip in which the diagnostic has run and
passed. |
| • | The history DTC will clear after 40 consecutive warm-up
cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using a scan tool. |
Diagnostic Aids
The crankshaft position system variation compensating values are stored
in the PCM non-volatile memory after a learn procedure has been performed.
If the actual crankshaft position variation is within the crankshaft
position system variation compensating values stored in the PCM,
DTC P0300 may set refer to
DTC P0300 Engine Misfire Detected
.
If the crankshaft position system variation learn procedure cannot be
performed successfully, inspect for the following conditions and correct any
conditions as necessary:
| • | The engine coolant temperature is below 70°C (158°F). |
| | Allow the engine to warm to above 70°C (158°F). |
| • | The powertrain DTCs set. |
| | The scan tool crankshaft position system variation learn function will
be disabled if any powertrain DTCs other than DTC P1336 are stored. |
