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Followup To
Question - It's not a question but a concern. When I took my car back, I was told that the brake pedal sensor was not seated properly (it wasn't turned enough) which caused the emissions problem. It was fix and, of course, at no charge. It is still a mistery to me why I did not have an emissions problem with the old brake pedal senor. However, thank you for your answers/comments. But please explain how sensors can fail because of neglect, overuse, and/or abuse. Thanks.
2000 S80 - What is the purpose of diagnostically testing if it does not let you know when a sensor is low or needs to be replaced? I had a 60000-mile checkup. Since then, I received the message "Performace Reduced," the throttle module, the mass air meter, brake pedal sensors and antenna ring around the key hole has been replaced. Today, I received the message "Emission System Service Required" and the check engine light. So why did that not show up on the diagnostic machine? Any comments/answers would be appreciated. Thank you.
Answer -
Well sensors do not have a predetermined amount of sensing they can do before they fail. Some fail due to neglect, some because of overuse, some for abuse, others for no aparent reason. The emmissions failure did not show up at your diagnostic appointment because it hadn't occurred yet. As much as we try to predict certain failures not all can be. It may be frustrating but your dealer will usually try to take care of you. If the problems were related (which they may be, upon further investigation), the repair shop would be obligated to refix the car if they either broke it or charged you for a repair that didn't fix the problem. Problems can only be tested and found when they're there so don't give your shop a real hard time about it. The only things we can accuratly measure life of is conusumable items like tires, brakes, fluids, and filters. Any further questions or specific concerns feel free to contact me.
James
AnswerHow sensors can fail (examples)
Neglect- If you fail to change your coolant as necessary, mineral deposits can begin to form which will coat all of the passages creating an insulator. This will cause your water temp to be measured in accurately and will have a significant affect on performance while warming up.
Overuse- Oxygen sensors. They go through a lot of warm up cool down cycles and they will give over time, always. If you plan on having a car for more then 10 years, you will be replacing an oxygen sensor. Plus they may form carbon deposits.
Abuse- Sensors/actuators that get alot of hands on from the driver fail this way if the driver goes over board. Accelerator pedal sensors, brake pedal sensors, window switches, door locks. I know not all of those things are sensor, but the corresponding sensors for those systems are just as likely to fail with abuse.
James
