About start-stop systems?

A start-stop or stop-start system in petrol or diesel powered engines is a system that automatically starts and stops a cars combustion engine when idling. Globally only a small percentage of cars have this feature, but is a growing feature in order to meet emission regulations. The main purpose of a stop-start system is to reduce your cars emissions and improve fuel mileage. This means when your car is idling it will shut down to reduce emissions and will turn back on when you go to accelerate. All hybrid vehicles come with this feature to further improve their fuel mileage. Most hybrids switch off or to battery power when idling or driving at a slow speed.


Start-stop technology has been around since the early 90’s, but since then it has had many improvements. Start-stop systems are constantly turning the engine on or off. This puts far more strain on the ignition system, and the starter motor and car battery. The constant extra use of the starter motor to restart the car means the starter motors have to be far more robust.

Each time the starter motor is used, it also puts an extra strain on the car battery. The car battery is usually constantly being used by your lights, radio and internal car features, windscreen wiper and so on. Start-stop technology is designed so that it turns off the engine but the battery is still able to power all the other features of the car. This means the car batteries have to be far more resilient. This includes being able to handle large amounts of energy being drawn by the starter motor, without affecting the other features in the car. When the engine is not running the car battery will need to last longer. This is because it needs to power the cars features while the engine is not running.

In combustion engines, there are a few requirements for a start-stop system to work. Some cars may have an indicator for when the start-stop system can be used. First, the engine must be at a high enough temperature for the engine to be able to start immediately. Usually once brakes are applied the car must come to a full stop, with no or very little steering angle before the engine will turn off. To start the engine again, you just need to release the brake pedal, or touch the clutch pedal. Other reasons why this system may not work include:

– The vehicles steering wheel is turned

– The driver or passengers seat belt is not on

– The outside temperature is too low, causing the engine to cool down

– The driver’s door is open (in some cars the passenger as well).

– Bonnet or boot are not locked

Learn more on start-stop systems


Causes of a start-stop system not working:

Damaged or old starter motor

Old or failed battery

With the constant extra load on the battery and starter motor, it is likely that these are the cause of a faulty start-stop system.


Start-stop diagnostics and repairs in Hamilton:

If there is a problem with your start-stop system, the team at Grimmer Motors will be happy to help. At Grimmer motors our reliable mechanics can easily diagnose the problem causing an issue with your cars start stop system.

For all start stop system repairs in Hamilton, contact Grimmer Motors today!


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