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Brief description

Brief description

The Saab Trionic T7 is an engine management system that controls air mass, fuel and ignition from only one control module.

When the driver depresses the accelerator, the accelerator cable rotates the pedal position sensor located in the throttle housing. The system requests a torque and the throttle motor rotates the throttle until the value of the throttle position sensor corresponds with the requested torque. The system has the following advantages:


• Turbo lag can be compensated.

• Emissions can be reduced in connection with load changes.

• Integrated idle speed control.

• Load compensation possible throughout the whole load and speed range.

• Efficient torque limitation as necessary.

• Cruise control easy to integrate.


Fuel injection is sequential and is controlled by the air mass flow.

Ignition is performed by an ignition discharge module. The spark plugs are used as sensors to detect combustion and knocking. This means that neither a camshaft position sensor nor a knock sensor is required.

Saab Trionic T7 has been developed by Saab and has great development potential.

New functions compared with earlier Trionic systems are:

Throttle body (604)


• Contains the pedal position sensor (rotated by the accelerator cable), the throttle motor and the throttle position sensor.

• Informs the control module of the driver's torque request.

• Rotates the throttle to the position determined by the control module.


Limp-home solenoid (607)


• Fed by a relay, the limp-home solenoid (640) is governed by the control module.

• Mechanically connects the accelerator cable to the throttle spindle if a fault arises in the throttle body or any of its leads. The mechanism must be reset manually.


Charge air absolute pressure sensor (603)


• Informs the control module of the pressure level in front of the throttle.

• Used for determining density of air in front of the throttle.


Dense air requires a smaller throttle angle.

Intake air temperature sensor (407)


• Informs the control module of the temperature in front of the throttle.

• Used for determining density of air in front of the throttle.


Dense air requires a smaller throttle angle.

Manifold absolute pressure sensor (431)


• Informs the control module of the pressure after the throttle.

• Used to correct the value from the mass air flow sensor during rapid load changes.


Mass air flow sensor (205)


• Sends frequency modulated information on the air mass flow to the control module.

• Acts as the main sensor for fuel injection.


P bus and I bus


All the control modules in the Saab 9-5 are connected to the bus with the exception of ABS, TC/ABS and SRS.

The bus is divided into the Powertrain bus (P bus) and the Instrument bus (I bus). Both buses are connected to the main instrument unit (MIU). The buses are electrically isolated from each other.

Data transfer is 10 times faster on the P bus than on the I bus.

All the information transmitted by one of the control modules is available to all the other control modules connected to the bus. MIU is responsible for making the information that is available on one bus also available on the other bus.