With fuel prices continuing to rise, UK drivers are facing yet another financial headache: inflated repair costs. New data from automotive diagnostics specialist Carly has revealed that motorists could be paying up to five times the standard cost for a simple oxygen sensor replacement. While the expected price for this repair is around £110, Carly’s undercover investigation found quotes reaching as high as £672 depending on the garage.
The nationwide mystery shop, conducted using the same SEAT Ibiza with a known fault, uncovered significant price inconsistencies across ten UK garages, spanning both independent and main dealer networks. While all garages correctly identified the fault code, P003100, many proposed repair costs far exceeding the expected standard. A Leeds-based national chain quoted £672 for replacing both oxygen sensors, a Stoke-on-Trent main dealer quoted £618, and a Sunderland dealer offered £328—highlighting how unpredictable pricing can be.
Beyond inflated costs, the investigation revealed a trend of unnecessary upselling. Four out of ten garages suggested additional services unrelated to the known fault, including brake replacements, spark plugs, air-conditioning servicing, and duplicate diagnostics. These add-ons could have increased bills by £400 to £950, often without clear explanation of urgency or necessity, leaving drivers feeling powerless and unsure.
The findings are supported by a OnePoll survey of 2,000 UK drivers, which shows widespread confusion and distrust. Over half of respondents feel garages have the upper hand in repair costs, with 45% unsure whether quotes are fair. Four in ten drivers say additional work is frequently recommended without a clear explanation. Confidence in self-diagnosing faults is low, with 51% admitting they cannot identify serious issues before a breakdown, yet 69% would still attempt a diagnosis themselves. The survey also highlighted perceptions of vulnerability, with 62% believing women are more likely to be overcharged and 53% feeling that drivers with limited car knowledge face the greatest risk.
Stuart Masson, Editorial Director at The Car Expert, said: “Rising fuel prices are putting extra strain on drivers’ finances, making it more important than ever to avoid unnecessary repair costs. Carly helps motorists identify, understand and solve issues early—keeping them in control of their maintenance spend. The real challenge isn’t just the cost, it’s the lack of clear information about what work is necessary and what a fair price should look like. Carly gives motorists the clarity and confidence to question quotes and make informed decisions before stepping into a garage.”
Emma Brown, UK Growth Manager at Carly, added: “This investigation highlights a clear information gap between drivers and garages. Many motorists don’t have the tools to understand what’s wrong with their car or what a repair should realistically cost. Carly is designed to close that gap, translating complex diagnostics into plain English and providing clear guidance on typical repair costs. It’s not about replacing mechanics, but helping drivers feel confident they’re paying a fair price.”
Carly’s smartphone app and scanner deliver real-time manufacturer-level diagnostics, fault code explanations, and repair cost guidance, helping motorists avoid overpaying and unnecessary work. By providing clear fault information and typical repair costs, Carly empowers drivers to approach repairs with confidence and avoid financial surprises. With prices starting from £40, Carly offers an accessible solution to one of the most unpredictable aspects of vehicle ownership.
