ENGINEERING CONFUSION; car clocking affects more than just the price

HPI & One Show reveal car clocking affects more than just the price

The BBC’s One Show last night put the spotlight* on used car clocking and the real issue facing consumers; seemingly anyone is able to take advantage of unsuspecting car buyers by winding down the clock and cranking up the value. But it’s not just the value of vehicles that is being affected; used car history expert HPI warns that the techniques used by modern clockers are affecting crucial readings in Engine Control Units (ECUs), potentially leading to both legal and safety issues.

As reported by the One Show’s Dan Donnelly, HPI has long been a forerunner in the fight against used car fraud, and continues to campaign against so-called ‘Mileage Correction Firms’.  These outfits are widespread throughout the UK, despite there being very few legitimate reasons for a vehicle to have its mileage altered.  HPI says due to the computerised systems on modern vehicles today, winding the clock back on a car can have serious ramifications over and above a false mileage reading.

Around 10% of all the modules in a modern car, such as the airbag, ABS and ignition, feed information into the central ECU system, and each time an event occurs – such as a faulty airbag warning – a ‘snapshot’ of the vehicle’s mileage will be recorded on these modules. Therefore, unless a vehicle’s mileage is wound back by a particularly ‘diligent’ and skilled clocker who alters the mileage readings on all potentially affected modules in addition to the odometer, these will be out of sync, leading to issues with safety warnings – and potentially legal cases in the event of an accident.

Shane Teskey, Senior Consumer Services Manager for, explains further, “Clocking is a blight on the used car industry. It’s too easy to do and quick to make money for a dodgy seller that many think, ‘Why not?’.  But here is a perfect example of why not – serious problems can be caused within a vehicle.

“Firstly, there is the potential to miss important servicing and warning light indicators, as the car’s various different components will be reading different mileages. By changing the mileage, a clocker will actually be causing conflicts within the cars electronics and interfering with the normal routines for servicing and repair. In addition, a manufacturer’s warranty is likely to be void if the car is discovered to have been clocked.

“There is also a very serious legal issue to be considered. In modern vehicles crucial evidence of a car’s performance and speed at the time of an accident will be stored in the cars on board computer. Such evidence may have an important contribution to make in a accident investigation but sadly if a vehicle has had its mileage tampered with, the integrity of the data could be said to have been compromised and likely inadmissible as evidence in court. So an innocent party in an accident could find themselves unable to prove this if they had been driving a clocked car without realising.”

The HPI Check produced at includes a mileage check against the National Mileage Register, which contains over 170 million mileage readings – and offers vital protection to consumers against buying a clocked car. will also uncover other potential problems such as if the is registered with the police as stolen, has been written-off by an insurance company or has outstanding finance against it.

Teskey concludes, “What this illustrates is how serious a problem clocking really is. We want to remind both used car buyers and the legislators that enable ‘Mileage Correction Firms’ to continue isn’t just a ‘financial fraud’ issue – as important as that is – but more vitally a question of safety, which no-one can afford to ignore.”

*HPI Reports on problem of clocking to BBC One Show:

About HPI:

Originally established in 1938, HPI Limited is a primary source of vehicle information for the UK motor industry and motoring consumer which, since December 2008, has been owned by Solera Holdings, Inc.   Solera Holdings, Inc. is an integrated group of leading automotive claims solutions companies. Founded in January 2005 by Chairman and Chief Executive Officer Tony Aquila, Solera has expanded its geographic reach and now serves more than 55,000 business customers in over 50 countries across six continents.

HPI encompasses both the HPI database of all UK road registered vehicle descriptions and histories, and the National Mileage Register (NMR) which holds in excess of 160 million mileage readings.

Together, HPI and NMR represent one of the UK’s largest vehicle information sources, combining and interpreting data from government agencies, industry bodies, private organisations, the police and the general public. Registering with HPI helps companies to protect their financial interests in motor vehicles and a wide range of other mobile assets. HPI Checks give purchasers instant confirmation of whether vehicles are correctly described, known to be subject to outstanding finance or serious accident damage, or recorded as stolen or “clocked”.

‘HPI’ and the HPI logo are registered trademarks of HPI Limited.

(1) All prices include VAT and are correct as of 2nd January 2014
(2) Mileage Data is not covered by The HPI Guarantee
*(3) The HPI Guarantee is subject to terms and conditions

Scroll to Top