SAAB WIS ONLINE

Control module

Control module


The ACC unit operates when the power supply is 10-16 Volt. Outside this range, the ACC unit shifts to the OFF-mode.

The control module is integrated into the ACC unit and is activated by +15 or the parking heater input. That the control module is activated can be seen as the display lights up and that diagnostics communication is possible. After having been activated from +15, the control module can take up the following conditions:

The engine is not running

If the engine is not running, no coolant will circulate through the heat exchanger, the A/C compressor will be stationary and the generator will not charge the battery.

As a result:


• the system cannot control the climate.

• the system should not use a lot of current unnecessarily

• and there is a risk that one of the stepping motors could miss a step due to low battery voltage should the starter motor be engaged.


For these reasons the control module selects electrically heated rear window and door mirrors OFF, fan current 5 A, recirculation OFF, and stops all stepping motors.

The engine is running

As soon as the engine has started, the control module automatically regulates all functions if no manual selections or other user programming has been performed.

Ignition OFF

When the ignition is turned off, the display shuts down, no buttons work, all stepping motors stop and recirculation OFF is selected. Diagnostics communication is maintained if it was active when the ignition was turned off, but it cannot be resumed.

The control module processor is active for another 10 minutes. If the ignition is turned on within these 10 minutes, the control module will retain the manual selections that have been made during previous driving. After the 10 minutes, the control module starts in the AUTO position or in user programmed position.

If the power supply drops below 9.5 V and the starter motor is not running, the display will show OFF until the voltage exceeds 10 V.

Programming

A number of parameters must be programmed when changing the ACC unit, see .

Diagnosis

In case of an internal control module malfunction, diagnostic trouble code B1605 is generated , 01 is shown instead of temperature at calibration.

Control module power supply



+30

The ACC unit is supplied with current from +30 via fuse 27 to pin 22.

+15

The ACC unit is supplied with current from +15 via fuse 9 to pin 4. +15 power supply is used to activate the control module.

The fan control and the cabin temperature sensor suction fan receive the necessary power directly from the ACC unit.

Diagnosis

If power supply is missing, the display will not light up when the ignition is turned on.

Ground



The ACC unit, cabin temperature sensor suction motor as well as fan control are grounded via the fan control connector at grounding point G34P (LHD) respective G33P (RHD).

Sensor ground

All sensors are grounded from the ACC control module.

Diagnosis

If ground is missing, the display will not light up when the ignition is turned on.

If the sensor is shorted to 5 V or B+, diagnostic trouble code B2945 is generated, 23 is shown instead of temperature at calibration.