Electronic Control Systems: Self-Diagnosis

WARNING: This page is about a different car, the 2013 Acura MDX, 2012 Acura MDX, 2011 Acura MDX, and 2010 Acura MDX. However, it is still accessible from the selected car via links, so may be relevant.

The PCM detects the failure of a signal from a sensor or from another control unit and stores a Pending or Confirmed DTC. Depending on the failure, a Confirmed DTC is stored in either the first or the second drive cycle. When a Confirmed DTC is stored, the PCM turns on the malfunction indicator lamp (MIL) by a signal sent to the gauge via the F-CAN A.

One Drive Cycle Detection Method
When an abnormality occurs in the signal from a sensor or from another control unit, the PCM stores a Confirmed DTC and turns on the MIL immediately.
Two Drive Cycle Detection Method
When an abnormality occurs in the signal from a sensor or from another control unit in the first drive cycle, the PCM stores a Pending DTC. The MIL does not come on at this time. If the failure continues in the second drive cycle, the PCM stores a Confirmed DTC and turns on the MIL.