The Service Engine Light illuminates regularly on my S40. The Volvo tech told me to loosen the gas cap and retighten. The light will go out but only temporarily. It is approaching it's recommended maintenance mileage. Could that be why the light keeps illuminating?
I had this problem on my 2000 S40. The htird time I brought the care in with this problem, I was angry, and the service manager decided to work on it himself. He suggested trying a new gas cap. As he put the new cap on, he commented that the design was a little different than the old one. The new cap fixed the problem. It seems that Volvo knows there is a problem with the cap that the car came with.
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