First of all, diagnostic fault codes never say to replace parts or that parts are defective. They only indicate the circuit or system that needs further diagnosis. About half the time there is something else wrong like corroded or stretched electrical connector terminals, bare wires, corroded splices, etc.
Second, there are a lot of codes related to each sensor and they mean vastly different things. Some get very specific, and some are not real descriptive. We need to know the exact code number to have a better idea of where to start.
Also, you should understand that the computers on the car detect problems by comparing sensor readings at different times to different things. As an example, the Engine Computer knows that when the engine has been off for a specific amount of time, the coolant temperature sensor and the intake air temperature sensor had better be reading the same temperature. If one of them sends an unacceptable voltage signal that results in setting a fault code, the computer knows it can't use that one as a reference for the second one, so even if the second sensor develops a problem, no code will be set because no tests will be run on it. It's not until after the first problem is fixed that the computer can resume running all the tests, and that's when it will detect the second problem. That could be why you are seeing the Check Engine light again. You have to start over by reading the codes again to see if it's the same one that is setting. If it's the same code, the sensor wasn't the cause and the circuit must be tested further. If there's a new code now, the computer wasn't able to detect it while the first problem existed.
Wednesday, June 5th, 2013 AT 12:22 AM