Control Module

Control Module

The transmission control module primarily controls
- Shift points
- System pressure
- Lock-up engagement

The control module has a 35-pin connector and is located behind the glove box in the passenger compartment. It is programmed for the B204i, B2041 or B234i and is to be used only in the Saab 9-3 together with the relevant engine variant. The control module receives information from a number of its own sensors and from other electronic systems. The information is processed and the control module governs the current gear and shifting point based on the selected driving program (Normal, SPORT or WINTER).

Shifting is achieved by the control module affecting the two solenoid valves, S1 and S2. The control module also determines if and when the torque converter Lock-up should be activated, which is performed with the help of solenoid valve SL. The system pressure in the gearbox is controlled by TCM.

The control module is continuously powered with +30 and is adapted for a voltage of between 9 and
18 V when running. Stored diagnostic trouble codes are deleted from memory when the power is cut.

When the ignition key is turned to the ON position, the control module will be activated and turn on the CHECK GEARBOX warning lamp continuously as a function check. The lamp is turned off by TCM after three seconds if there are no faults.

In the event of a fault in any of the inputs/outputs, the transmission goes into Limp-Home mode. All control module functions are then disengaged or an emergency operation program is activated. The car can then be driven but with limited shifting capability.

When handling control modules it is important to ground yourself first by touching the car's engine, for instance. Avoid touching the control module's connecting pins.

Diagnostics
If the control module's ROM or RAM is defective, diagnostic trouble code P0605 will be generated.