Console Shift

WARNING: This page is about a different car, the 2004 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.

The console shift system consists of the following components:

The park relay
The ignition 3 relay
The automatic transmission shift lock control switch
The automatic transmission shift lock control solenoid
The automatic transmission shift lock control relay
The rear integration module (RIM)
The powertrain control module (PCM)

With the ignition ON, battery voltage is supplied to the coil side feed circuit of the brake to shift relay. When the RIM receives a PARK signal though a class 2 serial data message from the PCM the RIM grounds the control circuit of the brake to shift relay. This energizes the brake to shift relay coil and closes the switch contacts in the relay. Battery voltages flows through the switch side of the park relay to the automatic transmission shift lock control switch. The contacts in the automatic transmission shift lock control switch are normally closed allowing voltage to flow to the coil side of the shift lock relay. The coil side of the shift lock relay is permanently grounded. This energizes the shift lock relay, opening the normally closed switch side contacts. With the switch contacts open the automatic transmission shift lock control solenoid de-energizes, locking the shift lever in the PARK position. When the driver presses the brake pedal the contacts in the automatic transmission shift lock control switch open, de-energizing the shift lock relay. The switch side contacts close and voltage form the ignition 3 relay flows through the shift lock relay contacts to the permanently ground automatic transmission shift lock control solenoid. The solenoid energizes and unlocks the shift lever, allowing the driver to move the shift lever out of the PARK position.

When the shift lever is moved out of the PARK position, the PCM sends a class 2 serial data message to the RIM. The RIM then opens the ground path of the park relay control circuit, de-energizing the park relay and the shift lock relay. Once the vehicle is out of PARK, the automatic transmission shift lock control solenoid remains energized or unlocked until the RIM receives a PARK signal from the PCM.