a camshaft position sensor or separate knock sensor. Comparison with Trionic T7 Compared with the earlier Trionic T7, the following functions are new: Throttle body actuator (604) Contains throttle position sensor and throttle motor with associated reduction gear. The throttle body is spherical to improve the throttle area control with low loads. No mechanical limp-home function as with T7. Accelerator position sensor (379) Integrated in accelerator pedal bracket. Ignition coil with integrated power module (320) Separate inductive ignition coils with ionization current measurement. Power stage integrated in ignition coils Combustion Detection Module (740) Combustion Detection Module (CDM) processes the ion current signal from the ignition coils first. Provides ECM with information on combustion quality and possible knocking. Exhaust temperature sensor (602) Measures temperature of exhaust gases after catalytic converter. Used as enable criteria for catalytic converter diagnosis. Pressure sensor, atmospheric pressure (539) New model located on engine instead of integrated in control module. Same function as in earlier Trionic T7 system. Power steering fluid pressure switch (739) Informs ECM when power steering servo pressure exceeds 17 bar. Used for idle speed compensation. Level monitor, engine oil (243) Informs ECM when oil level is low. Used for indication on Saab Information Display (SID). Level sensor, fuel (46) Informs ECM of current fuel level. Used for certain diagnoses and trip computer, and for indicating fuel level on main instrument unit (MIU). Relay, start relay (517) Controlled by ECM. Radiator fan control Radiator fan logic is in ECM that also activates the radiator fan relays. Radiator fan can run in four different modes. Generator (2) ECM controls whether the generator should charge or not. Used to engage generator charging with a certain delay after starting and in certain cases disengage generator charging. In this case, the engine load will be reduced temporarily when idling to stabilise the idling speed. Pressure monitor, engine oil (44) Informs ECM when oil pressure is low. Used for indicating on MIU and SID. Pressure sensor, A/C (620) Informs ECM of current pressure on the A/C system high pressure side. Used for load compensating, radiator fan operation and is sent out as a bus message to be used by ACC. Tuning Due to countermeasures implemented by Saab to protect their intellectual property, Trionic 8 systems are more difficult to reprogram. Despite those countermeasures, some tuning companies do offer performance-tuned Trionic 8 maps. References Saab engines Saab Trionic Engine control