Control module: Notes

Fig 1: Identifying Control Module

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Saab Trionic T7 control principally:

engine torque
fuel injection
ignition.

The Trionic T7 control module has a 70-pin connector and is located in the engine bay in front of the windscreen on the passenger side.

It has two processors. A number of sensors supply information to the control module, which processes it with the help of matrices stored in the control module after optimization of engine functions. Examples of these important matrices are the ignition timing matrices, fuel matrices and air mass matrices.

The control module can be damaged by electrostatic discharges or short circuits in any of the outputs. Great care must therefore be observed when handling the control module, such as when carrying out fault diagnosis with BOB.

The control module is continuously supplied with +30 and will lose adapted values and stored diagnostic trouble codes if this current disappears.

The control module is adapted for a voltage of between 8-16V when being driven.

When the ignition is switched on, the control module will be activated and the CHECK ENGINE lamp will go on continuously as a function check. The fuel pump is activated for 1 second so that fuel pressure will build up, after which the control module will await pulses from the crankshaft position sensor.

Fuel injection is controlled principally by the mass air flow sensor.

Substitute functions are available for all the sensors except the crankshaft position sensor.

An absolute pressure sensor for atmospheric pressure is integrated in the control module.

Atmospheric pressure is used to:

Fig 2: Identifying Control Module Atmospheric Pressure

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Correct the PWM ratio of the charge air control valve. At low atmospheric pressure, a greater PWM ratio is required to obtain the same air mass/combustion.
Correct the purge PWM ratio. At low atmospheric pressure, a greater PWM ratio is required to obtain the same purge flow.
Protect the turbo from over-revving at low atmospheric pressure by limiting the max. permissible air mass per combustion.
Block certain diagnoses:
- Block certain diagnoses at pressure lower than 72 kPa.
- Reactivate certain diagnoses at atmospheric pressure above 78 kPa.

Once the ignition has been turned off, all the sensors supplied with 5V are activated for 15 minutes. After 15 minutes, only the memory is active. Adapted values are stored in the memory.

NOTE: Adaptation is important to performance, driveability, fuel consumption and emissions. The control module must therefore not be disconnected or in any other way be de-energized unnecessarily.