Additional control system — general information

Additional control system (AWS) monitors the levels of fluid in the cooling and washer system, brake pad wear, outside air temperature and lamp operation. The system also issues a warning signal when the fuel tank cap and doors are not tightly closed.

When the fluid level is low and the pads are worn, the control lamps on the dashboard light up. The graphic display module located in the instrument panel provides a schematic view of the vehicle and information about defective lamps and doors that are not fully closed. Ice warning is given by two snowflake symbols on the graphic display module. A yellow snowflake lights up at an outside air temperature of plus 4°C and a red one at a temperature of 0°C. Information about the ambient temperature can, if desired, also be displayed on the digital clock display in the upper console.

When the ignition is turned on, all AWS warning lights and symbols in the graphic display module should turn on for a few seconds and then turn off (the brake light symbols will not turn off until the brakes are applied for the first time). If the lights remain on, the appropriate level or system should be checked immediately. If any light or symbol flashes, the indicated level or system must be checked.

The main components of the system, besides the signal lights and the graphic display module, are various sensors and control assemblies. Liquid level sensors are reed switches controlled by magnets installed in floats. The brake pad wear alarm is activated after a coil of wire pressed into the pad lining at a depth determined by the standards breaks on the disk. All sensors, including door open sensors, have contacts shunted with resistors so that the control unit can distinguish between closed and open sensor contacts and open or shorted circuits.


The bulbs are monitored by a bulb fault module located under the instrument cluster. The control is carried out over the lamps of side lights, rear lights and low beam headlights. The lamps are monitored in pairs, so the installation of a lamp of the wrong power, even on one side of the vehicle, will cause a warning signal.

Temperature sensors are installed under the front bumper. They are thermistors whose resistance changes as the ambient temperature changes.

The AWS system control assembly integrates inputs from various sensors and controls the lighting of warning lights and symbols. The low fluid level warning lights come on with some delay to avoid false alarms caused by vehicle vibrations while driving. If there is a problem with the AWS system, a thorough review and detection of the defect must be carried out by a competent person.