ACC Control Module, Changing

Things to remember when working with ACC
In order to avoid damage to the electronics in the ACC control module, proceed as follows:
- When arc welding, unplug the negative lead from the battery, the regulator connection and the 25 pin or 39 pin connector from the ACC control module.
- When taking measurements and conducting fault diagnosis, the 25 pin or 39 pin connector should be unplugged from the ACC control module.
- From year model M1988:
The cooling fin on the ventilation fan speed control is live (+12 V) when the ignition is switched on. If the cooling fin is grounded, speed control is destroyed.







To Remove
1 Switch off the ignition.
2 Remove the ashtray.
3 Pull the ashtray holder toward by bending down the two upper locking tabs.
4 Press out the control module from behind.
5 Unplug the 25 pin connector, -1989 or the 39 pin connector, 1990-.

Installation
6 If a M1994 ACC control module is to be installed in a car of year model M1990 - M1993, first carry out the procedures in "ACC Control Module Adapting" so that the control module will operate as intended. ACC Control Module Adapting
7 Plug in the connector.
8 Place the control module in position.
9 Clip in the ashtray holder and the ashtray.

Year model 1990-

10 Calibrate the ACC system by pressing the "AUTO" and "VENT" buttons at the same time.

Year model M95

11 The ACC control module as a spare part should be adjusted using the ISAT scan tool set to "ADJUSTMENT" and "SOLAR SENSOR". Select the value 33 and press the ESC button in order to store this value in the control module.

Important : During calibration, all previous diagnostic trouble codes are erased. Before carrying out calibration, all stored diagnostic trouble codes should be read.

12 Carry out user programming as required by the customer.