'Lambda sensor or engine management system failure, a faulty spark plug or air cleaner, a hole in the exhaust or coking of the catalyst are problems that would cause a car to fail the emissions test without necessarily requiring a change of catalytic converter,' said AA chief engineer, David Lang. 'This may avoid having to spend hundreds of pounds on a new converter.
'Far fewer catalytic converter-equipped cars are likely to fail the MoT emissions test than originally feared. Tests carried out this summer found a failure of 9% - compared with scaremongering predictions of up to 20%. This is in line with failure rates of 10% in Germany.'
Car owners or fleets affected by the new test are those with K-registered or later vehicles made by Alfa Romeo, Citroen, Daihatsu, Fiat, Ford, Isuzu, Jaguar, Lada, Mazda, Mercedes, Nissan, Porsche, Renault, Rover, Saab, Subaru, Toyota and Vauxhall. Catalyst replacements can cost as much as £601 (for the Peugeot 605 3.0-litre), £559 (for the Saab 9000) and £532 (for the Seat Ibiza 1.9D and 1.8), while Lambda sensors cost between £36 (for the Vauxhall Astra) and £284 (for the Honda CRX).