My wife took her 2002 RAV-4 for a service, which was uneventful. However, a few days later the engine management light came on, so back it went. The service dept at the Toyota garage said (and I paraphrase as I wasn't there) that it was one of the 'oxygen sensors', which I believe to be something in the exhaust system that tells the engine computer how much fuel to squirt in. The mechanic said it often comes on if supermarket fuel is used all the time, which in this case is true as my wife is averse to spending money (a trait I admire). Does this mean that supermarket fuel is actually deleterious to our car and if so should we claim against them for the repair?