Car clinic: Supermarket parking dispute, sensitive Prius alarm and rusty BMW brake callipers

Your motoring problems solved

The Car Clinic experts

Tim Shallcross used to train AA patrols to fix cars. Now he advises the Institute of Advanced Motorists.

Dave Pollard has written several Haynes manuals and has tested just about every car-related accessory.

Nick Freeman is a solicitor with a practice in Manchester that specialises in road traffic law


Q: I recently parked my Toyota Prius on my driveway, only to be repeatedly disturbed by the alarm going off. Eventually I drove the vehicle under the car port, locked it, and the alarm stopped. When a similar thing happened a year ago on a sunny day, a passer-by suggested it might be caused by hot weather. Toyota could not supply an explanation. Any ideas?

SD, London

A: There is a small compartment on the ceiling of most Toyotas, intended for sunglasses, which is near the alarm’s internal movement sensor. Items placed in this space have been known to trigger the car’s security device, so if you were wearing sunglasses and left them in there, that could be the problem.

Another explanation is that the hot weather has affected the car’s batteries and made the voltage fluctuate, which in turn has triggered the alarm. This is a fairly rare event, though, and is usually a sign that a battery is nearing the end of its life.

The Prius has two batteries: the large and expensive one that  is used to power the electric motors, and a small 12V one under the boot floor at the back of the car, near the spare wheel. This small one provides electricity when the main battery is switched off; it powers the electronics that turn on the main battery and start the car up, and supplies ancillary items such as the radio and the alarm.

Owners report that four years is a typical replacement interval for this battery, but do get it checked before you go ahead and swap it. It’s simply a small version of an ordinary car battery and is available from Toyota for £95, fully fitted under the company’s fixed-price repair scheme (details at The battery itself is available for less from Euro Car Parts ( at about £54, but it is quite awkward to get to and remove, so there will be a labour charge unless you are a competent mechanic.



Q: I recently received a “parking charge notice” for £70 from a supermarket car park operator. Apparently there were signs  (none of which I saw) stating that to qualify for free parking, customers must enter their registration in the store where I did my shop. The letter refers only to the date of the “event” rather than the “offence”. Advice online suggests I just ignore the demand, as it is unenforceable. Is this true? Also, am I obliged to give the company the name of the driver?

SL, Rochdale, Greater Manchester

A: The letter you describe uses different language from a penalty charge notice issued by a local council or the police because a private company does not have the right to fine you. It does, however, have the right to take you to court for breaking a contract. Basically, if you decide to use the car park, provided the terms and conditions are clearly displayed, you have entered a legally binding contract with the car park provider.

Should it go to court the case would hinge on how clearly and comprehensively the terms and conditions were displayed, and whether you were in breach of them. The company would also have to prove some sort of tangible financial loss. As there was no parking fee and you say you did spend money in the store, it could be argued there was no loss suffered and that you apparently had no reason to intentionally flout the rules.

If you would like to take matters into your own hands, provided the company is a member of the British Parking Association, you could consider an appeal to Parking on Private Land Appeals (, a free service. Challenge the charge along the lines I have outlined above — although you must first have made representations to the parking company, and it in turn must have rejected them.

The reason some people suggest ignoring the request is not because the charge is unenforceable but because the parking company would ultimately have to prove its case in the county court, and would not necessarily recover the cost of bringing the case. This means some firms simply threaten to issue legal proceedings but never follow through.

As for your question about naming the driver, since October 2012 the law states that a vehicle’s registered keeper is now responsible for all parking charges connected with it, unless they are able to identify someone else as the driver on a specific occasion.



Q: The brake callipers on my 2012 BMW 3-series have gone rusty. It is a special-edition model with M Sport wheels, which means the rust is very visible through the spokes. Surely this should not be happening on a £35,000 car less than a year old.

ST, Charing, Kent

A: Wheel hubs, wheels, brake discs and callipers are under constant attack from moisture in the air and rainwater, and in the winter months from road salt (which accelerates corrosion). This is why brake discs will usually get a light coating of rust within as little as 24 hours’ exposure. Brake callipers, however, are usually more resistant.

As your car is less than a year old, raise the problem with your dealership to see if it would be willing to make a contribution towards repair or replacement. To strengthen your case, look for similar models on the forecourt and check out their callipers (with the hope that these will be rust-free, showing a disparity in your favour). Keep a note of names, dates and conversations in case it is necessary to make a formal written complaint to the dealer principal at a later date.

Some high-performance models have painted callipers, which is a good way of fending off rust, so if you would rather avoid the fuss and simply fix the problem, have yours sprayed with a special paint. This is heat-resistant and extremely tough, and comes in a wide range of colours. It usually costs between £7 and £15 from car accessory shops, depending on brand, colour and supplier.

The callipers have to be removed and thoroughly cleaned before spraying, so it’s a job best left to a garage. Expect to be charged for half a day’s labour.



Got a car problem?

Email your question to, or write to Car Clinic, Driving, The Sunday Times, 3 Thomas More Square, London E98 1ST, with a daytime phone number, your address and as much detail about your car as possible. We can’t reply personally, so please don’t send original documents or SAEs. Advice is offered without legal responsibility.