Therefore, every time you disconnect the terminals from the battery to avoid unforeseen consequences remember the following:
- the engine control unit will lose stored information, such as engine idling and various operating conditions, as well as any detected trouble codes. After disconnecting and connecting the battery terminals, the control unit will take some time to restore all lost parameters;
- on models with electric locks, be sure to remove the key from the ignition and keep it with you so that you can open the car after connecting the battery and accidentally operating the locks.
- use devices known as «memory keepers». They will help avoid some of the above problems. As a rule, this device, which is a battery with a small capacity, is plugged into an outlet instead of a cigarette lighter while it is disconnected from the battery. «Keepers of memory» provide power to the engine control unit to store information and fault codes stored in the unit's memory, and also provide clock operation and store radio station frequencies stored in the radio receiver's memory. Using «memory keeper» be aware that voltage is supplied to the electrical equipment of the car, so before working, disconnect the relevant electrical circuit or component.
- cars are equipped with security systems (SRS), including airbags and seat belt tensioners. Before carrying out work near the shock sensors, the instrument panel and the steering column, first disconnect the negative and then the positive terminals from the battery and wait 2 minutes. This will prevent unauthorized deployment of the airbags and deployment of the seat belt pretensioners, which could cause injury.