Circuit Description
Timing of the combustion event is accomplished by controlling the begining
of injection measured in degrees of crankshaft rotation before top dead center.
This test compares desired timing to measured timing when certain
conditions have been met. To retard injection timing the PCM extends
the stepper motor. To advance injection timing the PCM retracts the
stepper motor.
Conditions for Running the DTC
| • | The PCM performs this DTC diagnostic continuously. |
| • | DTCs P0251, P0335 and P0370 not set. |
| • | No change in desired timing greater than .5 degrees for a minium
of 20 seconds. |
Conditions for Setting the DTC
| • | A 5 degree difference between Act. Inj. Time and Des. Inj.
Time |
| • | All of the diagnostic set conditions met for 2 seconds. |
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) on the
second consecutive drive trip that the diagnostic runs and fails. |
| • | The PCM records the operating conditions at the time the diagnostic
fails. The first time the diagnostic fails, the Failure Records will store
this information. If the diagnostic reports a failure on the second
consecutive drive trip, the Freeze Frame records the operating conditions
at the time of failure and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the MIL off after three consecutive trips without
a fault condition. |
| • | A History DTC will clear after forty consecutive warm-up cycles
when no failures are reported. |
| • | The use of a scan tool. |
Diagnostic Aids
Important: Remove any debris from the PCM module connector surfaces before servicing
the PCM module. Inspect the PCM module connector gaskets when diagnosing/replacing
the moduel. Ensure that the gaskets are installed correctly. The gaskets
prevent contaminate intrusion into the PCM module.
An intermittent may be caused by the following:
| • | Rubbed through wire insulation |
| • | Broken wire inside the insulation |
A hard start and possible poor performance condition might exist. Act.
Inj. Time will freeze at the point of the fault. Its possible DTC P0216
will set if injection timing is not set correctly. Refer to for
correct procedure.
Opens or shorts to ground in any of the control circuits may result
in full advance and very noisy operation.
