Spark Timing Monitor Test

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The PCM is equipped with a spark conduction capture circuit which measures the timing and duration of the spark delivered by processing the flyback voltage signal from the primary side of the ignition coil. When the cold start emission reduction monitor is enabled, the spark control strategy in the PCM commands the spark timing strategy to retard the spark timing. While retarded spark timing is requested, the spark timing monitor compares the measured spark timing from the spark conduction capture circuit to the commanded spark timing from the spark control strategy. For the purpose of detecting spark timing failures, the spark timing monitor increments a fault filter if the measured spark timing is advanced by more than 5 degrees from the commanded spark timing. A failure is indicated if the fault filter exceeds a value of 200, equivalent to a failure duration of approximately 4 seconds.

Spark timing monitor test operation:

DTC: P050B cold start ignition timing performance
Monitor execution: once per driving cycle, from start up with the cold start emission reduction monitor active
Monitor sequence: none
Monitoring duration: 7 seconds

Spark timing monitor test entry conditions:

Engine speed is between 400 RPM and 2,000 RPM
Engine position and cylinder identification are synchronized
There are no concerns with the ignition coils primary circuits