Traction Control Module: Description and Operation

Control Module, Description Of Function
TCS control Module
- The TCS control module has a 35 pin connector and is located under the left-hand front seat, which is moved forward in order to make the control module accessible for removal.
- When the TCS throttle butterfly actuator motor is without current, the butterfly is held in the open position by a spring.
- When the ignition is placed in the drive position, the actuator motor turns the throttle towards the fully open position for 128 ms and in doing this makes sure that the butterfly really is fully open. The actuator motor is then without current (while the butterfly is held fully open by the spring) and after a further 128 ms the value from the butterfly position sensor is stored in the control module as "fully open butterfly".
- As soon as the car's speed exceeds 4 km/h and the engine speed exceeds 600 rpm, the TCS throttle is synchronized with the ordinary throttle provided that the system is not manually switched off and that wheelspin does not occur.
- After starting, at the point of the first engine braking with fully released accelerator pedal, a new control of the function of the TCS throttle is made, and the throttle closes completely for 128 ms. This value is then stored in the control module as "fully closed butterfly". With the accelerator pedal still fully released, the actuator motor is without current for 256 ms, during which time the butterfly should open with spring power to at least 250 throttle valve angle. After this the TCS throttle is once again synchronized with the ordinary throttle.
- With the ignition off or when there is a fault in the system, the current to the actuator motor is immediately broken and the butterfly opens completely with spring power.
- When there is an internal fault in the control module, a diagnostic trouble code is registered, the TCS OFF light goes on and the TCS system is switched off.
- As a spare part, the control module is unprogrammed and must therefore be programmed during installation using the ISAT. For the Saab 9000, the TCS control module is programmed according to the type of gearbox in the car, manual or automatic.

Important A previously used control module may be programmed for the wrong type.





Control Module Voltage Supply
Battery Voltage +30 From fuse 21, +30 is supplied to pin 32 on the control module. The voltage is used by the control module to feed the throttle actuator motor.
If the +30 voltage is absent, the TCS OFF lamp lights and the system is switched off. If the +30 voltage should break, the control module will retain any diagnostic trouble codes stored in the memory.

Battery Voltage +15 With the ignition key in the ON position, + 15 is fed to pin 28 on the control module via fuse 13. The voltage is used to activate the system.




Grounding Points
- Pins 13 and 30 in the control module are grounded to grounding point G5. Pins 13 and 30 are internally linked in the control module and are electrically the same point. The grounding points are doubled to increase safety.





Input Signals To The Control Module
- Switch, ON/OFF (pin 1)
- Engine speed signal (pin 6)
- Speed signal, FR (pin 7)
- Speed signal, RR (pin 8)
- Speed signal, RL (pin 24)
- Speed signal, FL (pin 25)
- Position signal, main throttle butterfly (pin 11)
- Position sensor, Traction Control System (TCS) throttle butterfly (pin 27)
- Diagnostics lead K (pin 9)*
- Brake light switch (pin 23)
- Voltage from +15 (pin 28)
- Voltage from +30 (pin 32)
- Ground (pins 13 and 30)
* also output signal





Output Signals From The Control Module
- Position sensor, TCS throttle butterfly (pin 3)
- Position sensor, TCS throttle butterfly (pin 20)
- Disconnection, cruise control (pin 5) - )
- Disconnection, full-load enrichment system (pin 21)
- TCS function lamp (pin 12)
- TCS OFF warning lamp (pin 26)
- Diagnostics, K lead (pin 9)*
- TCS throttle butterfly actuator motor (pin 18)
- TCS throttle butterfly actuator motor (pin 35)
* also input signal