Fuel System Monitor

Fuel System Monitor

The monitor operates continuously throughout the trip. The monitor timing is every 0.128 seconds. The monitor compares the long term adaptions for the current load site against a failure threshold. If the adaptions for that site are greater than the failure threshold, the long term failure counter is incremented. If this counter reaches a calibrated time, the monitor looks at the short term fuelling trim and compares this against another threshold. The short term failure counter is incremented and if this counter reaches its failure threshold then a failure is flagged.

The normal counter operates when both long term and short term fuelling is within the thresholds. If the normal counter reaches its calibrated time then both failure counters are reset.

The diagram below shows the flagging of a rich failure on bank 1 of an engine:



















Fuel System Secondary Trim
On the X-Type from 2004 model year, a secondary monitor also checks the sub feedback trim levels. When the entry conditions are met, the sub feed back trim level is checked against a threshold. If it is either above or below a threshold, a counter is started, if at the end of the count the level is still above or below the threshold then an appropriate DTC is flagged.