Theory Of Operation

The purpose of the diagnostic is to detect an incorrect dog clutch position due to either hydraulic, electrical or mechanical failures. The actual position of either dog clutch A or F is calculated based upon the pressure variation resulting from the dog clutch actuation. The pressure is measured by a pressure sensor. A symptom of an incorrect dog clutch position is detected if the actual position does not correspond to the commanded position for greater than a calibrated amount of time. A fault is set, when the number of symptoms is greater than a calibrated threshold.

An additional diagnostic is performed immediately after engine restart. The time between the states "initialization" and either "engaged" or "disengaged" is monitored. If the time required between the "initialization" state and the recognition of the "engaged" or "disengaged" state is greater than a calibrated threshold, a fault is stored