QuestionQUESTION: My check engine light comes on and Auto Zone tested it and it reads there is a problem with the Oxygen and/or Knock sensors. The Oxygen sensor has been replaced. How do I find and replace the knock sensor?
ANSWER: Hi Chris,
I'm not going to tell you where to find your engines knock sensor and here is why, because there's nothing wrong with it.
Your knock sensor probably isn't bad just like the O2 sensor probably wasn't. AutoZone monkeys only know how to hook up the device and read the DTC's. They don't know what they mean and it's apparent you don't either.
DTC's are given as an indication as to what the problem could be. They are NOT telling you the pieces are bad and need replacing, the codes are pointing you in the direction of the REAL problem which is affecting the O2 sensor as well as the knock sensor. If I were to guess, I'd say you are using 87 octane gasoline and your engine wants something sweeter.
Increase the octane rating of the fuel you are buying, you know, buy the next highest grade which is probably 89 octane and run a tank-full through your engine. If it likes it, it will cancel the code and the check light will go out.
The computer is telling you that there is a lean or rich bank on the engine and that the knock sensor is out of spec. This, to a certified technician, is pointing right at cheap gas. But if you'd like, keep replacing the working components on your engine until you find your way to the fuel tank. I can't help you replace parts until you find the right one, have the vehicle diagnosed by someone who DOES know what they are doing and stop guessing.
Looking for a reputable service technician? My advice on finding a good technician is: Steer clear of the dealership and 'chain' stores like Firestone, Sears, Pep Boys, Monro Muffler/Brake, Midas, etc. as they usually only employ ONE ASE Certified Tech just so they can say they do and chances are, that guy is the asst. manager or manager and is not in the store to diagnose/repair vehicles anyway. Find a service location in the link below or get some names out of the yellow-pages and do a drive-by. Garages that employ ASE Certified Technicians will be marked with the 'Blue-Seal' insignia. If unsure about whether a place employs Certified Techs, just ask to see their credentials. ALL ASE Certified Technicians will be PROUD to show and display their certificate(s).
Thanks for the question, I hope this information was helpful to you.
Fred
Knucklebusters Used Auto & Truck Parts, Inc.
www.knucklebusters.us
570-453-0910
"Re-use is the best form of recycling" Help us recycle by purchasing used parts from us!
Looking for an ASE Certified shop near you? ASE Certified Technicians are the BEST of the BEST!
Click here: http://www.ase.com/bluesealsearch/locator.php
---------- FOLLOW-UP ----------
QUESTION: I bought this car after the oxygen sensor was replaced and the ex-owner said his mechanic said the light was coming on due to cheap fuel being used. Since I received your response, I have ran several tanks of higher grade gas and the check engine light stays on. The car is running great. Any other suggestions?
AnswerHi Chris,
You may have to access the computer and remove the stored codes. Sometimes if a code is present for a long time, the computer just stops listening to it and keeps the SES light illuminated. When a new sensor is installed, the resistance value is different which immediately alerts the ECM to a change and it runs a quick service diagnostic which will usually turn off the SES light after it finds that the sensor is not the same as the old one. Typically, the light will come back on as soon as the new sensor gets coated with whatever additive the other ones got, probably carbon since something is not operating as it should. You really should take it to a tech that can do a live-scan. A live-scan allows the tech to see what the readings of each sensor are in real-time with the engine running. A good tech will be able to determine from the raw sensor data what setting or sensor is out of range.
Looking for a reputable service technician? My advice on finding a good technician is: Steer clear of the dealership and 'chain' stores like Firestone, Sears, Pep Boys, Monro Muffler/Brake, Midas, etc. as they usually only employ ONE ASE Certified Tech just so they can say they do and chances are, that guy is the asst. manager or manager and is not in the store to diagnose/repair vehicles anyway. Find a service location in the link below or get some names out of the yellow-pages and do a drive-by. Garages that employ ASE Certified Technicians will be marked with the 'Blue-Seal' insignia. If unsure about whether a place employs Certified Techs, just ask to see their credentials. ALL ASE Certified Technicians will be PROUD to show and display their certificate(s).
Thanks for the question, I hope this information was helpful to you.
Fred
Knucklebusters Used Auto & Truck Parts, Inc.
www.knucklebusters.us
570-453-0910
"Re-use is the best form of recycling" Help us recycle by purchasing used parts from us!
Looking for an ASE Certified shop near you? ASE Certified Technicians are the BEST of the BEST!
Click here: http://www.ase.com/bluesealsearch/locator.php
