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Control module

Control module


The transmission control module primarily controls


• Shift points

• System pressure

• Lock-up engagement


The control module has a 45-pin connection and is located behind the glove box in the passenger compartment. It is programmed for either B204i, B204E B204l or B234i and must only be used in Saab 9-3 together with the engine type in question. The control module receives information from a several sensors of its own and from other electrical systems. The information is processed and the control module regulates engaged gear and shifting point based on the selected driving program (Normal, SPORT or WINTER).

Shifting is performed when the control module acts on the two solenoid valves S1 and S2. The control module also determines whether the torque converter Lock-Up should be activated and when, which it does with the help of the SL solenoid valve. The system pressure in the gearbox is controlled by TCM via a system pressure solenoid valve.

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.