Avoid a car breakdown

Common faults you can get around

As the UK's largest breakdown service, we fix more vehicles by the roadside than anyone else. Below, our breakdown team share some common faults they're called out for – that you as a driver can avoid.

Flat battery

Flat batteries are most commonly caused by leaving the lights on for a prolonged period of time after the car's engine has been switched off.

What does the battery do? It provides power to the starter motor, and then the running engine turns the alternator, which recharges the battery.

The battery can also be exhausted by:

  • leaving your car unused for a while, or only used for short journeys
  • a faulty component
  • a problem with the car's charging system
  • a fault with the battery itself
  • old age

So don't forget to switch everything off as you leave the car. Removing the ignition key may not switch off the lights, but most modern cars have a 'lights on' warning sound as you open the car door.

Also, most car batteries have a guarantee of 3 to 5 years, so you're living on borrowed time after then.

It's a good idea to have a pair of jump leads in your car, just in case. You could then recharge your battery from another vehicle. Read our advice on how to use jump leads.

Here's how our breakdown patrols deal with a flat battery. They will:

  • test your battery
  • check your car's charging system
  • check for a fault that could be draining your battery

The patrol will then charge your battery, or replace it if required, so you can continue your journey.


Flat tyre

Punctures, like flat batteries, are usually greeted with a groan. They're commonly caused by a sharp object, but other reasons include:

  • failure or damage to the tyre's valve (where air is pumped in and let out)
  • kerbing the tyre or a deep pothole
  • separation of the tyre and rim, following a collision
  • old age (worn tyre tread, even if still legal)

Replacing a flat tyre with the spare one is normally straightforward, but requires the correct use of a jack plus the tyre itself can be quite heavy and dirty. Read our step-by-step guide on how to safely change a flat tyre. And for all things tyres, check our tyre advice pages.

If you're an AA Member, our breakdown patrols will be happy to help if you're unlucky enough to get a flat.

Here are a few tips to minimise the risk of punctures:

  • Punctures are more likely when your tyres are worn, so replace them when the tread gets low.
  • Remember the driving test? Drive around, not over, corners and kerbs. The sides of your tyres (where there isn't any tread) are especially vulnerable to damage.
  • Have your wheels checked for alignment or 'tracking'. The correct steering alignment ensures your vehicle drives in a straight line – otherwise the tyres wear unevenly and this can even affect the handling.

The spare tyre is usually kept in the car's boot – make sure it's correctly inflated. The spare is not checked as part of the MOT test.

And some cars now come with a post-puncture sealant instead of a spare. The sealant is injected through the valve, though be warned, it can't be considered a permanent repair.


No fuel – or wrong fuel

Running out is perhaps the most embarrassing 'breakdown' drivers call us out for. When the needle goes on the red (or bleeps), some people simply overestimate how much fuel is still left in the tank.

If your tank is low:

  • fill it up sooner rather than later
  • top up the day before a long journey

Of course, our breakdown patrols are always on-hand to assist even if you simply need a few litres to get moving again.


Putting petrol into a diesel car, or vice versa, is another common 'breakdown' – around 150,000 drivers a year make this mistake. The second mistake is to start the vehicle. If you have filled up with the wrong fuel, just push the car off the forecourt to a safe place, and call our dedicated Fuel Assist team. They'll come to your rescue.

It's an easy mistake to make, so double-check the pump nozzle before you pull the trigger:

  • green for petrol
  • black for diesel

The diesel nozzle is also larger, so it can be harder to mis-fill a petrol vehicle.


Lost keys

If you lose your key or lock it inside your car, you're going to need help to get back in. Keeping a spare car key at home is a good idea, but little use if you're far away.

That's where the Key Assist team can step in and get you back into your vehicle in a jiffy. Our trained technicians are kitted out with keys and the latest key-programming technology for most vehicles, and are Disclosure and Barring Service checked, so you know you're in safe hands.