Faulty Engine Control Units (ECU) topped a list of the most frequent enquiries to Motor Codes’ UK advice line.
The top five reasons for calls to the helpline also included drivers who were seeking advice for vehicle problems in the following areas: Cam Belts, Head Gaskets, Oil Leaks and Injectors.
Car owners in the South-East and London had the most trouble with vehicle maintenance, making up a third of the total calls about car servicing and repair.
The East of England followed the South's lead making up 15% of calls to the line.
The regions with the lowest advice line usage were Northern Ireland and the North East, both at a figure of 1%. This was closely followed by Wales at 3% and Yorkshire at 5%.
Chris Mason, Motor Codes managing director, said:
"The good news is that the vast majority of calls to our advice line are for exactly that - advice - and the serious side of looking at where the most satisfied customers are is that only 7% of calls last year relating to Motor Codes garages required any formal intervention."
Motor Codes, the self-regulatory body for the motor industry, is hoping that its Garage of the Year contest will give drivers guidance on where to locate quality UK garages.
More than 6,500 garages have already signed up to the contest, which is based on public votes. Garages, both independents and franchised dealers, will be scutinised in terms of their quality of work, value for money, and customer service levels.
"Motor Codes exists to provide peace of mind for motorists, directing people to a nationwide network of garages committed to government-backed codes of practice," Mason adds.
"By nominating your garage, you help others choose a reliable business with confidence, cutting out the cowboys."
