Limited drive mode

The petrol engine control system is equipped with a program "limited controllability", which works as follows.

If during the movement the self-diagnosis system of the BZU detects any malfunction of the sensors, actuators or their circuits, then the program starts looking for options to replace the failed signal with something else to continue engine control. For example, if the engine temperature sensor fails, the program replaces it with an oil temperature sensor signal.

If there is no such sensor or it is also faulty, then the system replaces the sensor signal with a constant value, which is stored in the BEU memory. This ECU feature allows the vehicle to continue moving, albeit with less efficiency. In any case, by car you can get to the garage or to the nearest service station. The driver is notified about the transition of the BEU to the limited controllability mode by a signal light.

It is recommended to seek and fix this kind of malfunction with the help of specialists.