Sub-£20 diagnostic app could predict problems with your car and prevent costly breakdowns

Driver suffered breakdown and calling recovery provider with bonnet raised - £20 diagnostic tool could help them find the problem themselves

Other than taking their car for its annual service, it’s highly likely most drivers only find themselves at a garage when something has gone wrong with their car. By then, the damage could be extensive and their car off the road. The bill that follows will have owners wishing there was some way they could prevent such unpleasant surprises.

Now telematics technology is riding to the rescue. A new generation of on-board sensors, affordable diagnostic tools and user-friendly smartphone apps is at hand. It means drivers could know there’s a problem with their car long before it conks out.

Breakdown service providers, app developers and aftermarket product manufacturers are leading the drive toward real-time monitoring of cars. These enable drivers to stay one step ahead of trouble on the road. And in the future, it could help garages too. Here’s what drivers need to know to keep their car fit and healthy.

What is telematics?

Formula One racing cars have used telematics for years. Computers in the car monitor much more than you’d imagine. This ranges from the battery to different parts of the engine, the exhaust system to the brakes. When problems are identified – whether it’s a battery losing charge, a punctured tyre or clogged diesel particulate filter – messages are stored on-board. Telematics enables this information to be relayed to a third party. In racing cars, this is the pitwall. For regular drivers it can be their garage or breakdown provider.

How is telematics information accessed?

Male and female mechanic inspecting tablet while connected to car diagnostic port to find the problem
Technicians access information about a car’s precious parts via the diagnostic port


Generally, for cars made after 2005, there are two ways a car’s computers will share information on problems. The most common approach is when a portable diagnostic unit is plugged in when the car is taken to a garage. This is a bit like visiting a doctor and having your vital signs checked.

Increasingly, however, more drivers are choosing to have a monitoring device fitted by their breakdown provider. This is then left connected to the vehicle.

Either way, the connection is made via something known as the on-board diagnostics (OBD) port. This is effectively a direct route into the car’s various electronic brains. It looks like a socket found in the back of a television, and will be hidden beneath the steering column or passenger glovebox.

Which breakdown providers offer a car diagnostic tool?

The first company to bring a diagnostic app to the market was Green Flag. It launched Alert Me in 2016. Nick Reid, head of automotive technology at Direct Line Group, said: “Although breakdowns can’t be avoided every time, with Green Flag Alert Me drivers will be saved from unnecessary breakdowns caused by faults they weren’t aware of. Now we’ll be with them on the whole journey, letting them know about potential issues before they turn into problems.”

The AA introduced its Car Genie product earlier this year, and the RAC is finalising its equivalent for release to drivers.

How much does diagnostic telematics cost from a breakdown provider?

Green Flag charges £35 a year for its Alert Me service in addition to the cost of annual breakdown cover. The AA’s Car Genie is £29 a year on top of a driver’s chosen level of breakdown cover.

Are there independent apps that claim to do the same job?

Mechanic using diagnostic tool to inspect car engine and find the problem

There’s a good number of car diagnostic apps on the market, across Apple iOS and Google Android operating systems. These tend to be either free or inexpensive at most. Drivers should browse reviews to decide which best meets their needs. They’ll also need to invest in a portable OBD port adapter. This typically uses Bluetooth or wifi to send data to the user’s smartphone app. Some apps, like Engie, come with the adapter included for £19.99.

Do users have to agree to share data and location details?

Location and data sharing doesn’t have to be used with smartphone app programs, or portable diagnostic tools that are developed by independent providers. But household brands, such as the AA and Green Flag, will monitor such information. This enables them to locate and rescue drivers should a breakdown be recorded.

How will a diagnostic app help technicians fix cars?

Car manufacturers, original equipment suppliers, vehicle franchises and independent garages are sharing more and more data. As this is made available by the manufacturers, it can help steer technicians in the right direction as they maintain or repair modern cars.

According to Mark Schaefer, director of marketing at Snap-on Diagnostics in America, technicians can now access a detailed analysis of millions of repairs performed by garages. This can give mechanics a head start when solving a problem with a car. “It gives the technician an idea of where to look,” says Schaefer. “We walk them through the process of where to connect, what to test for, and what to look for.”


James Mills

James is a motoring journalist and former magazine editor at BBC Top Gear and Auto Express. He has scooped, reported on and reviewed most new cars of the past 20 years, and currently contributes to the Driving section of The Sunday Times.