Enhanced Testing

P1372 - Misfire Detection: Segment Time Acquisition Incorrect







Function
A Misfire induces a decrease in the engine speed and causes a variation in the segment period. Therefore, misfiring detection is based on the observation of this variation of the segment period.

DTC Description
Because of the tolerance in mechanical machining and assembling process of the target wheel, the duration of each segment are not always same but differ from segment to segment on the same engine. And this irregular segment duration can disturb misfiring detection which is based on the difference of engine rotational speed between the firing and the misfiring cylinder. The ECM compares segment duration of 4 cylinders during fuel cut-off and deceleration period. With this comparison ECM perform segment adaptation to adapt the difference of each segment duration.
The ECM sets DTC P1372 if any of segment adaptation value is on the limit. If the same error code is set in the next driving cycle, the ECM illuminates the MIL.


Detecing Condition and Signal Waveform