Calibrating

The stepping motors in the ACC system have no feedback to the ACC control module for damper position. For this reason, these must be calibrated to their end positions before use. In M1990-, this can be done via the ACC panel. In older year models, this is done manually.

The air mixing damper is calibrated to 0 % heat and the air distributor is calibrated to defrost.
Calibration must be carried out in the following cases:
1. After changing the stepping motor
2. If the battery has been disconnected or discharged.
3. If the ACC control module connector has been disconnected.

The ACC system is calibrated using the ISAT scan tool or by pressing the "AUTO" and "VENT" buttons simultaneously.

A self test also starts during calibration. Calibration and self test are carried out in parallel and take about 30 seconds.

The number of detected faults is shown on the ACC display. A maximum of five faults can be stored at the same time. All faults stored before calibration was carried out will be erased. If no faults are discovered, the ACC display will show set temperature.

If the ignition is switched off during calibration, calibration continues when the ignition is switched back on again.

When calibration is completed, the ACC system returns to the previously selected functions.