Theory Of Operation

The purpose of the diagnostic is to monitor the solenoid valve actuation of the dog clutch A, dog clutch F and the parking lock (if equipped). A solenoid valve is actuated by an on/off output stage that is controlled by the low level software. Solenoid actuation is commanded by the high level application software in the Transmission Control Module (TCM). After this command has occurred, the diagnostic checks the functionality of the low level software, microcontroller output pin and on/off output stage.

The monitoring is performed by measuring the voltage drop at the drain of the on/off output stage. This voltage is compared with the actual battery voltage to detect whether the on/off output stage is actuated