It is an electronic control unit (ECU), either dedicated or integrated into the vehicle's main ECU. Its function is to decide when to automatically switch the engine off and on, in order to reduce CO2 emissions. Within a matter of seconds, it analyses multiple vehicle parameters to make that decision — for example, how long the vehicle has been stationary, how long the brake has been held down, and so on.

The Start/Stop control unit evaluates numerous parameters in real time before deciding to switch the engine off, such as:

• Vehicle speed.
• Whether the vehicle is in neutral or the brake is being applied.
• Engine temperature.
• Battery charge level.
• Whether the air conditioning is active.
• Exterior temperature.
• Brake pedal pressure.
• Steering wheel position.

When the conditions to resume driving are met — by pressing the accelerator or releasing the brake — the Start/Stop control unit sends a signal to restart the engine almost instantly. This is made possible by a set of reinforced components:

• A reinforced starter motor designed to withstand multiple start cycles.
• An AGM or EFB battery — high-performance batteries specifically built to handle the demands of the system.
• Some systems use a motor-generator to start the combustion engine and recover energy during braking.

If you're wondering whether you can disable it permanently, the answer is no. What you can do is disable it temporarily by pressing the corresponding button on your vehicle's dashboard. However, it will reactivate after a short while.

No, because manufacturers have designed these components with reinforced parts to withstand the highest possible number of start cycles. As long as you keep up with the proper maintenance of your vehicle, you won't have any problems.

It may not switch off because the system does not detect the comfort or safety conditions mentioned above. It may also be due to:

• Insufficient battery charge to guarantee the next engine start.
• The engine is cold and has not yet reached its optimal operating temperature.
• Engine power is needed to run the air conditioning or heating.
• The steering wheel has been turned sharply.
• Reverse gear is engaged.
• The seatbelt is unfastened or not properly secured.

No, they are not the same, although they are related. To put it simply, an ECU is the main brain of the car, controlling all aspects of the engine. The Start/Stop control unit is a separate control unit that communicates with the main ECU. It is also possible for its functions to be integrated into the ECU itself, as an additional module.

If the one in your vehicle is failing and needs to be replaced, it is a worthwhile option to consider, as it will be more cost-effective than buying a new one. At Recoautos we stock a huge range of models for all types of vehicles and makes, so we're sure to have one that fits your car! And if we don't have it, we'll source it for you!

No, this job should only be carried out by an experienced mechanic. It requires specialist tools and involves working on many parts of the vehicle, so it is best left in the hands of a professional.

As a general rule, this is a feature that comes as standard. If your car is older and you want to add this component, it will require extensive modifications. Additionally, this work can only be carried out by a qualified mechanic.