how much for ultratune for the CEL diagnosis? That report is very responsible.. For your O2 sensor, they do need to change after certain kilometers for every car no matter what brand and it did trigger a CEL, so it is normal I have to tell you one story about Toyota for checking the spare tyre, most people did not check it. My friend has deliberately took out the spare and took the car to service, and the report comes with spare tyre being checked !!! My friend called up and complain straight away, and the manager asked my friend to bring the car back. WTF !!! For toyota, you have to think the other way round, how much salary did the mechanic get paid per hour? Do you think they will take care of you..They got loads of customers, they don't mind losing one... Also, last time I brought the car to Bob Janes T Mart for a free inspection, I was watching them far away.. One of the item is to check the wheel alignment, they did not do it. Another item is to check the battery, they did not do it.. I won't bring my car to them next time.. I always go to private mechanic, if they do not do a good service, you won't find them next time..and they care about you. Of coze, you have to deal with the owner... It has come to my conclusion that cutting corners are common for mechanics. Bit hard to trust mechanics these days