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I stopped at 'business name removed' (a local auto parts store) because my check engine light was on. One of the staff hooked up some type of scanner to my car and told me I needed to replace the "oxygen sensor". I called a local repair shop to see how much replacing the sensor would cost. The shop I spoke to told me that the sensor may not be the problem, and that "diagnostics" should be done to identify the actual cause of the check engine light. They want $100 just to do the diagnostics! I have two questions: 1) which person was right? 2) is the diagnostic charge reasonable? (it seems very high)

Answers from the Automotive Experts

Stephanie Gutierrez, Marketing Communications Coordinator at Victory Auto Service & Glass Hi Chris! Great question. It can be so hard to know who's telling the truth in these kinds of situations. Here's what I would recommend. Many times when scanning for codes, auto parts stores can mislead people (intentionally or unintentionally) into thinking that what the scan tool says is the one and only problem. Sometimes they are right, but a lot more often they are wrong. A car, like the human body, is complex, and problems are often caused by more than one thing. Diagnosing a vehicle with a scan tool is like a doctor diagnosing someone after running only one blood test. There's often a lot more to it than that. Personally, I would recommend having the problem diagnosed at a trustworthy, reputable repair shop. Some vehicles have more than two oxygen sensors (some have four). So if it was an oxygen sensor, a technician should figure out which one has failed. And even though the scan tool picked up the oxygen sensor code, it could be something else that is the issue (several things could cause this). Every shop has different charges for their diagnostics. Some problems are difficult to diagnose and can take a while, and technicians charge an hourly wage, so that would account for the high fee. But you could call around to a few shops and ask for their approximate diagnostic fee. It also never hurts to ask if they are currently running any specials or have any online coupons you could use to lower the cost. I'm a big couponer, myself :) But it would be awful if you spent the money to replace the sensors and then found out later that that wasn't even the real problem. I have found tremendous value in sticking with the same technician for the last few years. I have saved SO much time and money by not taking my car from shop to shop, never knowing who will say or do what. My trustworthy tech keeps me and my family safe and my mind free of worries. Best of luck! Stephanie Gutierrez

Amanda J. Pierce, MBA Chris, Most certified repair facilities charge around $75-$100 diagnostics. This is based upon shop labor rates per hour in your area. Yes, there are other factors that may cause your check engine light to come on related to the O2 sensor that can cause drivability issues and poor fuel economy. I would call and get various quotes on diagnostics to have an average cost.

Audra Fordin, Owner at Great Bear Auto Shop Hi Chris, Well, both shops are kinda right. Sometimes the scanner does give a code that will direct you directly to the cars trouble. Sometimes, further diagnosis is necessary. As for the reasonable charge, well, I do not charge to give estimates or to run scans on a car. Im sure many shops do not charge for that as well. However, if there is extensive electrical diagnosis necessary, I do charge for that. Without looking at the car, I can only assume that a scan will reveal the necessary repairs. The oxygen sensor is usually a common problem that frequently requires replacment. If it is more than the O2 sensor, still, a simple scan will determine that. The place that wants to charge you, ask if they incorporate the diagnosis fee into the repairs. Mechanically yours, Audra www.womenAUTOknow.com

Lori Johnson, Owner and Instructor at Ladies Start Your Engines Dear Chris, While the check engine light gives you a code, it is true that simply replacing that part may not fix the problem. Sometimes there is another problem that causes the sensor to go bad. I would call around to get other prices for diagnosing your problem. A Nissan dealer I called recently told me it would be $105 to diagnose my check engine light. Good luck. Lori Johnson www.ladiesstartyourengines.com

Pat Fleischmann, Director of First Impressions at Community Tire Pros & Auto Repair Both answers are correct, but for a shop to make the correct repair and warranty the work- the shop needs to perform its own diagnostics and find out "which" Oxygen sensor is out and if the others are weak and may go out soon. $90.00 to 110.00 are accurate pricing. These diagnostic machines are very expensive and complicated as today's vehicles are mostly computer...that being said~ I always compare it like going to a Dr. and the first thing they require is usually an Xray or blood tests for a Diagnosis! Kinda the Same analogy? We can't take the diagnosis from another shop as we don't know if they've missed something or have UP-To-DATE software!

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