Theory Of Operation
WARNING: This page is about a different car, the 2012 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.
Four solenoids are used to control the friction elements (clutches). The continuity of the solenoids circuits are periodically tested. Each solenoid is turned on or off depending on its current state. An inductive spike should be detected by the PCM during this test. If no spike is detected, the circuit is tested again to verify the failure. In addition to the periodic testing, the solenoid circuits are tested if a gear ratio or pressure switch error occurs. In this case, one failure will result in the appropriate DTC being set. The MIL will illuminate and the transmission goes into Neutral, if the DTC is set above 35 Km/h (22 mph), limp-in mode when vehicle speed is below 35 Km/h (22 mph).