"Service Engine Soon" light on a 2002 Mitsubishi Diamante

[bennyandthejets]

You should get a code for the exact sensor not providing the signal the PCM is looking for. Not necessarily a bad sensor, but a sensor not providing a signal the PCM is looking for. It will say sensor 1 bank 1 or sensor 1 bank 2 or sensor 2 bank 1, etc. This will isolate the sensor. THe guys at autozone should know enough to give you that information. But wait a minute, maybe not. They do get training, but for many of them, it is all module training, and no hands on training. You might have a bad sensor after all, if you had someone experienced watching the cross counts in a “monitor” mode on the sensor, they can determine whether or not the sensor is bad. If it is totally dead, then yes, your sensor needs changing. This is why some mechanics get paid what they do, because they are more than parts changers. They have the ability to understand what’s going on with your engine, versus just reading a computer and changing parts that are suspect. While I’m on my soap box, let me share one more thing that grinds my gears: everytime I hear someone tell me they got their car fixed at the shop and paid $800, because the car computer and the ignition module went out, or the yada, and the yada (fill in your own parts) went out, I immediately suspect they threw parts at the problem until they found the root cause. Sometimes, but not often, one part can in fact, cause another to go out. But usually, it is a bad initial diagnosis, so the general rule is to say "yeah, the flux capacitor caused your widget-mabob to go out. Thank you for listening. (stepping down off soap box) That is all I have to say about that.