Eliot Silverman

Eliot Silverman
Owner

Wednesday, June 6, 2012

That Darn Pesky "Check Engine Light"

Check Engine Light
The computer’s function is to minimize pollution. It has many sensors and solenoids it can actuate (cause to turn on and off) to monitor, adjust and fine tune your car to minimize its pollution.  When there is a problem with a component in the computer control system, the computer illuminates the “Check Engine” light or it illuminates the “Picture” of an engine.  For the rest of this article, I’m going to refer to these lights as (check engine light) CEL.

When you see the CEL on there is a problem.  I shake my head, and quiver when I hear a customer say, “The last mechanic said there was nothing wrong with my car.” If there was nothing wrong, the light would be off!  I am also amazed when I’m told by a customer that the last mechanic said they did not need to repair the problem.  Later you will know why this is a bad, bad idea.

When a car is here because the CEL is on I use a tool called a  “Scanner”  to connect to your computer.  One of the displays on my scanner is a number which is referred to as a code.   This first step is referred to as “Pulling a Code.”  Each problem for which your computer turns on the CEL has an associated number or “Code.”  Pulling a code does NOT tell me what part is bad- it tells me what area in the computer control system is/was malfunctioning.  I then print out a diagnostic chart related to this code, and I print out an electrical schematic for the problem area.  With these two print outs, and some other diagnostic tools, I can diagnose your computer system’s problem.  Most of computer diagnostics take between 30 and 45 minutes.

Three Possibilities When Your CEL Is On:
1.        The problem will affect performance.  For example, if your ignition coil went bad your car to run rough.
2.       The problem will NOT affect performance.  For example a bad gas cap allows the gasoline fumes from the gas tank to leak into the atmosphere.  A bad gas cap does not affect performance but it does pollute the air.
3.       The part which is bad will not affect performance, but left unchecked, it will cause another part to go bad.  For example, a bad oxygen sensor, on most cars, will not affect performance, but if it went bad and you left it on your car it will cause the catalytic converter to go bad.  Replacing the oxygen sensor when goes bad saves you a lot of money. 


Here’s another reason to repair a part that will not affect performance
Let’s say your last mechanic said the CEL is on because of a bad gas cap.  You choose not to replace it since it will not affect performance, nor will it cause any problem to any other part in your car.  That is correct….. but, three months later the oxygen sensor goes bad.  You don’t know it went bad since the computer does not have a ‘second’ CEL, nor can it make the CEL get brighter to inform you that another part went bad.  By the time your car is not running well, and you bring it in for repairs, you’ll need to replace the oxygen sensor and the catalytic converter.  Therefore, not replacing an inexpensive part, cost you hundreds of extra dollars in repairs.

Can The State of Illinois Make Me Fix MY Car?
Cars 1996 and newer need to have an emission inspection every two years.  These inspections, to be official, can only be done by a State of Illinois Emission Center, and you may only go for an inspection after you receive a notice from the State of Illinois.  If you pass the inspection, the test center notifies the Secretary of State, and your license plate is renewed. 

If your CEL is on, you’ll fail the emission test, and the State will not renew your license plate until you repair the car or they issue you a waiver.  Basically, waivers are only issued after you have spent money trying to repair you car. 

98 comments:

  1. The check engine light is obviously one of the most common things related to automobile repair but it can mean many different kinds of things.

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  5. Thanks for the advice. I ended up taking my car into a shop that does auto repair in Langley because my Check engine light was on. It didn't end up being a big deal, but it could have been. Glad I didn't do any real damage to my car.

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  7. I just wonder how often your check engine light comes on? is it supposed to be something common? or can i get it fixed at auto repair langley? thanks :D

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  10. The check engine light is certainly pesky. My light kept going on because the catalytic converter was messing up and each time I went to the mechanic, he would do something to turn it off but it would come on again real soon and it was such an annoyance. Plus, if it is always on for a non significant reason, then if there really is a serious problem, you won't know it because you will just assume it's on for the same old reason. It's like the boy who cried wolf. Anyway, thank you for this post, really interesting article.

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  11. My check engine light was on so I figured it was just time for an oil change. I took my car in for auto repair near Kelowna and when I got my car back, the light was still on! Turns out, sometimes a guy can just forget to turn it off. It happens to all of us, doesn't it?

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  12. You know what is hard sometimes? My engine lite always turns on, even after I just took my car into the auto repair in Victoria, BC. I just ignore it now because nothing has been wrong and my car is working great. Hopefully I am doing the right thing.

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  13. I just recently got in an accident and I am in need of finding an auto repair shop in North Vancouver. I just moved to the area too and I am hoping to know what is going on.

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  18. Another informative post from you about engine light, however I am hoping to read something like auto bearing service in your future post because I am interested in this kind of topic.

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  20. This week my check engine light came on, so I took my car to the local shop. Come to find out, there were many other problems with the car. I had to also fix my alignment and one of my tires had a hole in it. I had to take the car to a place that offered tire services in Champaign, IL. Now my car runs much better than it did before.

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  22. Oh, definitely, one should never just ignore a warning light. I mean, even if it turns out to not be a big deal, it's always better to know what's wrong than not know. "There's this blinky warning light on my dashboard. It's probably nothing. Doo de doo de doo..."
    (engine blows up)

    As for not getting auto repair to replace a minor part, then having to pay much more when that minor part causes a major problem? There's a reason the phrase "Penny-wise, pound-foolish" was created.

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  24. I need to take my car in to get looked at. My car is pretty old and I've noticed it hasn't been driving well lately. I don't know if it is just old, or if there is a problem.

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  25. Last week, my check engine light came and I panicked. Isn't it a bad thing if that comes on? I need to find an auto repair shop in Waterdown to help me fix my car.
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  26. Thanks for this post! My check engine light came on twice in the last month, both times because the gas cap was loose. I didn't know that could cause the light to come on! I felt really silly when my mechanic told me that was the problem, but I feel better knowing a professional diagnosed the issue.
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  27. The check engine light turned on while we were driving in Death Valley last summer. It was 120 degrees, and I didn't know what to do. My family was already getting fussy from the long drive, and I didn't want to have to pull over to the side. How do I avoid having this happen again?
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  28. I have only had the check engine light come on for me twice. I take my car in for regular checkups and you would be amazed at what they can prevent. I am just happy that my little car has help up as well as it has for the past 15 years.

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  29. My check engine light is on all the time. I don't know how to get rid of it. I think I'm just going to have the car repair place turn it off for me. I'm pretty sure my car is going to be fine even if that light is off. http://www.jensentireandauto.com/service.html

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  30. It's really important to pay attention to the check engine light. Mine has only come on a few times in my car. Each time I took it to the shop right away, and it has saved me a lot of trouble that would have happened later on.
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  31. I have a red Hyundai that is a couple years old and lately the check engine light has been coming on. I have taken it in to the shop several times, but the light never turns off. I don't know how to turn it off, but I guess if it's still running I should be ok.
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  32. Funny story about the check engine light. The light in my grandpa's car was on for years and he got annoyed with it, so he just taped a piece of black tape over it and that was that lol. Not the best thing to do of course. Anyway, great post man.

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  33. My mom's car had the check engine light stuck on for about six months. We went to a mechanic and they looked at everything. They reset the light after they determined it was nothing. Now it's back on and I have to help my mom find someone to help her with it.
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  34. Last week, my check engine light came on and I don't know what to do. I'm sure that it is nothing I can fix on my own. Hopefully I can find an auto repair shop to take the car to near Tacoma, WA. http://www.coopersautorepairspecialists.com/services.asp

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  35. There's nothing worse than being out in the middle of nowhere and having your check engine light turn on. You never know when your car could just break down. I always make sure I get my car checked before I take a long road trip. http://www.earls-garage.com

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  36. This is great advice for auto repair services. I always feel like people ignore the check engine light for too long. And I am guilty of that. http://www.japshopinc.com/Transmission-Maintenance-Brake-Repair-Wilton_Manors-FL.html

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  37. My brother had an old Nissan Altima that he loved. As soon as the "check engine" light would appear on the dash, he would take it straight to an auto repair place close by. That car has lasted 15 years thanks to making sure everything ran perfect. You have great advice on keeping your car running smoothly for as long as possible.

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  38. Great post. If ever that your vehicle has a problem don't hesitate to bring to a shop with auto repair services. Don't ignore those small problems because it may cause big big problems to you.

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  39. Thanks for this information on the check engine light! My check engine light always seems to come on and I'm sure what to do about it. I also didn't know that if my CEL light is on it wont pass emissions. Thanks again for the tips!

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  40. I would never risk driving with my "check engine" light on. I am very cautious when it comes to cars and driving. I take my car into auto repair shops frequently to make sure that everything is running okay. I don't want to risk any accidents that I could have prevented.
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  41. A couple of months ago we had some problems with our engine. Luckily we were able to catch it early on, and diagnose that the spark plugs were the problem. It is really true what you say, paying 100 bucks to replace spark plugs is so much cheaper than replacing your entire engine. http://www.autorepairandtires.com/Auto-Repairs-Auto-Maintenance-Huntington-Beach-CA.html

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  42. This is a great post. So many people ignore the check engine light because they do not know what it means, but it is a very obvious sign that something is wrong! I always recommend that you bring in your car to a car repair service when that light comes on. It may be inconvenient, but you can save a lot of time and money by getting a problem fixed early.

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  43. I've had this issue with my car so many times -- I turn it on, and up comes the check engine light! However, your post shows that there may or may not be something wrong with it, which is great to know. I never thought about your third possibility, that it could cause something else to go bad. I'll have to see if I need anything fixed or if it is just a glitch. http://www.prairietire.com

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  44. I think the check engine light is the number one problem I've had with my cars. It seems that every once in a while they decide to just get stuck on. I sometimes it's something wrong with the car, other times it's just a short. Either way, it's rather frustrating. http://nationaltransinc.com

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  45. How do make sure my check engine light is working? It's on and has been for a long time. I haven't had any problems. I've had it checked several times and no problems have been found. is there a way to make sure the light isn't just broken? http://www.showroomimport.com/Marietta-import-foreign-auto-repair.html

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  46. My wife's CEL light has been on in her car for a long time and since she will have to get her car re-registered soon I need to find a cure, this article was very helpful and I will make sure to get it repaired as soon as possible. I didn't realize that it could be polluting the air. http://www.bluevalleygarage.com/our-services

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  48. I don't think that my car's check engine light has ever gone off. It never really concerned me until I read your article. I just had to have my timing belt replaced, and it was not cheap. If I had paid more attention to that pesky light, I may have been able to avoid that major repair.

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  49. My check engine light has been on for the past two years. I haven't had any problems with my car yet, but it just won't turn off. I'm really nervous because I won't be able to pass the safety and emissions test with it on. http://www.minittune.com/en/

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  50. My car is about to break into pieces. At least that's what it feels like when I drive it around. I really need to find a car repair shop close by soon. I don't want to break down in the middle of no where. http://www.southsideautorepairlex.com/services.html

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  52. Me check engine light has been acting funny. It will turn on and then off several times. Should I get it looked at? http://www.xlautony.com/about

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  53. I honestly have never really taken the check engine light too seriously. It does get me a little worried but it usually turns back off after a few days. It was nice to get some more information about what that little light means. I may have to take my car to an auto repair shop.
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  54. I have the biggest issues with my check engine light. The computer reads that the gas cap is leaking really. I have already replaced the cap and I reset the light but it keeps coming on. The error code is the same, but it doesn't seem to be the other issues like air intake etc. Should I just take it in to get repaired or is it just the pesky light trying to push my buttons?

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  55. Fixing my car has been an adventure like none other. I have taken my car to five different places to have it checked. Everyone has given me a completely different quote. What are these people doing?

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  57. I recently got into a car accident. I took my car to a couple of auto shops to get the damages fixed. Each one of them had different quotes, and different policies. I am so stuck, and I really need some help with what to do in my current problem.

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  58. My engine light went on in my truck. I know that my struts are pretty bad in my car could that be causing the problem? Or are, they haven't connected, I really need some help. What do you suggest I do?

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  59. You never know as to why a check engine light comes on, but it comes on for a reason. When it does come on, it is a good idea to get auto repair services or at least take it into a shop to be checked. That way you can find out what is truly going on with your vehicle and you can go about things the right way.
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  61. I just bought a used car a couple of weeks ago. Just last week the check engine light came on. I have heard lots of people say the same thing and that there was nothing wrong with the car. I am wondering why the light is on and what should I do about it?



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  62. I honestly think that they need to make more lights that let you know specifically what is wrong. I get very anxious when the check engine light comes on because I think something huge is going wrong. Lately, my light comes on and off because there is a problem with my gas cap. It isn't causing any harm at all. It comes on and off all the time which is really annoying, but I know nothing is wrong. http://www.autorepairhighdesert.com/

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  64. I never knew that the check engine light functioned as an emissions regulator also. Now I understand why my light has been going off and I have checked the engine multiple times and seen no problem. When I get the funds I will have to take it into a professional and see what they can do about it.

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  65. Thanks for sharing this! I just noticed the check engine light on my car, and I am not sure what to do. It was just serviced last week, so there shouldn't be anything wrong with the car! I guess I'll go have it checked out soon, especially if not doing anything can cause more damage to the car. I definitely don't want that! http://www.timscollision.com/about

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  68. It's very interesting that repairing parts that don't directly affect performance is still a really good idea. I didn't realize that there were so many other issues that could be caused by a small problem with the check engine light. It seems like that's always the first thing to go crazy in a car. I'll have to make sure that I stay on top of the CEL and keep it functioning properly. http://www.tyreandwheel.com.au/mechanical

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  69. I recently had a check engine light coming on and off in my car, and it was actually a really easy fix. I got a diagnostic test and found out the problem was just a loose gas cap. I was able to repair it for only a few dollars. http://palmertireandauto.net

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  70. This was very insightful. I don't know much about cars and have assumed that as long as the problem does not affect performance then it is not actually a problem. I'm curious, what are all the systems and functions that the check engine light computer monitors? http://www.transmissionclinic.com

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  72. It is great to know the three reasons why your check engine light would be on. Mine has been on for the last couple days and I have not been able to figure out why. Perhaps I should just take it to a shop so that the problem does not escalate. http://www.dicksautoservice.com

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  91. The light could mean a costly problem, like a bad catalytic converter, or it could be something minor, like a loose gas cap.

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