Engine check light, how do I turn it off and why does it go off?
- Thread starter Imaginer
- Start date
Post make and year of car. I can do it on a nissan, but other cars im sure are different.
On another note. If the car is drivable, go down to autozone, they will pull the codes for you. I don't think they are allowed to clear the codes anymore though. But at least you will have an idea of whats wrong.
Could be a HUGE list of things wrong. Mine has gone off when my Mass Air Flow sensor died, and then when the ECU died. It's good because you can look up what the code means and then go from there.
On another note. If the car is drivable, go down to autozone, they will pull the codes for you. I don't think they are allowed to clear the codes anymore though. But at least you will have an idea of whats wrong.
Could be a HUGE list of things wrong. Mine has gone off when my Mass Air Flow sensor died, and then when the ECU died. It's good because you can look up what the code means and then go from there.
yes they will Imaginer. More often than not it is one of the many sensors on your car that is malfunctioning or that is not working at all.
Autozone Diagnostic Service
edit: fixed
Autozone Diagnostic Service
edit: fixed
They can tell you the codes. The codes do not tell you what is wrong or what to replace, all
they tell you is where to start your diagnosing.
Once you're tired of spending money on sensors they tell you to replace, then you can go to a real shop and get it actually diagnosed, instead of just having the codes pulled.
Again, pulling the codes is NOT diagnosing the concern.
I can't believe I didn't think about this first, and I apologize Imaginer. First thing you need to check is your gas cap. On a lot of cars, the check engine light will come on if you don't have the gas cap on properly or tighten down properly. Not sure if it does on that year model Ford Ranger., but you need to read your truck's manual as it will tell you about the check engine light and what you need to do. Pacfanweb is correct. The codes that autozone will pull won't tell you what sesnor or part is malfuctioning, but they should let you know if it is a serious malfuction or not.
In my experience it could go either way. The code they pull could be dead on, exactly what is wrong. Or it could be related to a bigger problem. In my most recent car, it has been dead on, exactly what was wrong. Call me fortunate.
I say it could not hurt to see what codes come up. Usually some degree of description will come up on the scan tool. But to learn more you can always go online and do a google search for the code.
You can also call up local mechanics and see if any diagnose for free or for a small fee.
As opposed to somebody who can barely operate the scanner pulling codes for you and
offering advice as to what to replace?
I can't tell you how many cars I've had come in where the owner was pissed because he/she had already spent 2-400 bucks at either some "tune up" shop, or buying sensors at Auto Zone or Advance, only to come to us and get the proper diagnosis the first time.
And every time they'd say basically this: "What do you mean it'll be 150-ish to fix it? I've already spent 300 bucks for this same problem".
Not with me, you didn't. You could have spent 150-ish with me from the start, which includes the 70 or so buck diag fee. But no, you thought that was too much, so you tried to get it diag'd for free.
Now, as a caveat, I was working at the largest Ford dealer in the Southeast. At the time, we had over 70 techs.
If we couldn't fix it, it couldn't be fixed. There is no way that SOMEONE in our shop wasn't able to figure out what was wrong with even the most stubborn problems. The Ford engineers in our district brought their problem-child cars to our shop so we could help them figure out the problems.
So that's my definition of a "real' shop, but as I said, it really isn't a fair comparison to most shops. I'll still take most any factory-trained mechanic at at dealership's diagnosis over some code-reader at the parts store, any day.
usually.. its for an oil change, unless u got one recently and you're sure u don't need one then just read ur manual or use GOOGLE and reset it
try disconnecting the battery from the truck for 1min the reconnect ( you will have to reset your clock) but this has taken care of 80% of the ones i have encountered in the garage in the past. its basically rebooting the computer in the truck. if not id get the codes checked and go from there.
Check and make sure you put the gas cap on. If it's there, just take it off then screw it back on tightly.
If car is recently idling roughly, perhaps you got a bad tank of gas recently? (this happened to my mom's car a couple days ago; tank was about 3/4, so I topped it off with some quality 93 octane and light went away). I'm guessing she got some borderline 87 octane stuff before.
Other than that, I definitely concur with others about going to Autozone and have then evaluate the check engine light for free.
If car is recently idling roughly, perhaps you got a bad tank of gas recently? (this happened to my mom's car a couple days ago; tank was about 3/4, so I topped it off with some quality 93 octane and light went away). I'm guessing she got some borderline 87 octane stuff before.
Other than that, I definitely concur with others about going to Autozone and have then evaluate the check engine light for free.
- Oct 15, 1999
- 8,076
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Thanks for the input everyone, I am sure the gas cap is on good but will check that, otherwise I will check with seeing what Autozone pulls up for codes and do a bit of info search of what caused it. Taking it to a dealer and having it checked out sounds like a safe plan but I am not sure how much runaround they will give me if any. Same with other auto shops.
Well, a dealer will probably charge you $75 just to pull the code. Getting the code and the description is only really going to help you if youre good enough with cars to do something about it.
On my old dodge neon, you could get the codes on the dash by just flicking the key in a certain pattern - I pulled a code regarding my evap system, and after searching, it was just the infamous loose gas cap that throws that code.
Back when I bought my celica, the CEL light was on, the car was stumbling a bit, and I told the guy I at least needed to know the code before I'd consider buying it. He went to a mechanic, and it pulled a code relating to a misfire. The mech wanted to change all the plugs, wires, O2 sensors and MAF to the tune of several hundred. I searched the code on newcelica.org - turns out it's a common problem, the code fires when the MAF sensor gets dirty. I of course didnt tell the guy that, and bought the car at a pretty steep discount. Took it home, sprayed a little brake cleaner on the MAF (the recommended fix), and it drove like it was new.
So the point is...sometimes you can throw a code and it'll be a quick and easy fix, but no matter what code you throw, a mechanic will want to replace every possible thing related to it. It's at least worth a try to figure it out yourself.
More often than note it is a sensor ayabe, but not necessarily. Sometimes it can be a more problem other than a sensor which could lead to a more serious problem if you keep driving with the check engine light on. In some vehicles the check engine light may flash as well denoting a more serious problem than if it stays on all the time. I've been fortunate in that every time mine has come on it was the sensor. However, on my 92 GrandPrix, it was my dang gas cap. I bought a new locking gas cap for it about two years after I got it, and it would was a royal pain to get back on after you took it off to fill up. My check engine light started to come on. I was all set to take it to the shop until I read the manual. Got a another gas cap that fit better, and the check engine light went off. I wish all vehicle problems were that simple to fix.
There are something like 250+ codes that the engine light could be from, and most of them have little to do with the engine.
They're called "dummy lights" for a reason - you're a dummy if you ignore them. I wouldnt drive a car with the CEL on for very long unless I definitively knew it was something that could wait.
Keep in mind that for the CEL caused by a gas cap, it may not go off instantaneously...it might take ~100 miles or so for it to go away, depending on the car.
The ghetto way of figuring out how serious the CEL is is to disonnect the battery, and then see if it comes back on. I wouldnt recommend that unless youre broke and your car is already a POS though.
The easiest fix is putting a piece of black electrical tape over it, though I'd recommend removing the bulb.
Just reading the code is NOT what they charge you for. Again, getting the code only tells you where to begin your diagnosis. There is no code that you get that automatically means "replace xxx part". What the dealer is charging you for is taking that code and doing the pinpoint tests necessary to tell you what is actually wrong with the vehicle.
Autozones and the like cannot do this. All they can do is read the code, and look up what it means. So if they get a code that means "Oxygen sensor reads rich", that does NOT automatically mean you need an oxygen sensor. If the sensor is reading rich, that might mean the car is actually running rich. Which the oxygen sensor can cause, but lots of other stuff can cause that, too. Maybe you'll get lucky and the sensor that is setting the code is actually the problem....maybe not.
exdeath
Lifer
- Jan 29, 2004
- 13,679
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It could be one problem or a backlog of multiple problems. It could be a temporary problem that goes away after the computer sets a time out flag on that code if it doesn't occur again for x time.
Important thing though is: does it run any differently? Most of the time the light comes on for harmless emissions control junk, and the engine itself is just fine. (EVAP fault due to loose gas cap for example).
Last time the light went off on me, I pulled the code with a scanner and the result was multiple misfires on cylinder four. So pulled off the coil pack cover, pulled out the coil packs, and checked the plugs... in the process it was discovered somehow a little water worked its way down into the spark plug recess and was grounding the #4 coil pack directly and bypassing the spark plug completely. A little compressed air, and problem solved.
Nice thing about a V8 is you don't really notice you are missing an entire cylinder just driving around town.
Important thing though is: does it run any differently? Most of the time the light comes on for harmless emissions control junk, and the engine itself is just fine. (EVAP fault due to loose gas cap for example).
Last time the light went off on me, I pulled the code with a scanner and the result was multiple misfires on cylinder four. So pulled off the coil pack cover, pulled out the coil packs, and checked the plugs... in the process it was discovered somehow a little water worked its way down into the spark plug recess and was grounding the #4 coil pack directly and bypassing the spark plug completely. A little compressed air, and problem solved.
Nice thing about a V8 is you don't really notice you are missing an entire cylinder just driving around town.
exdeath
Lifer
- Jan 29, 2004
- 13,679
- 10
- 81
It can be pretty much anything you can imagine.
The engine computer pretty much knows everything. They are wired up in so many ways to the engine that most newer OBD II systems even have stuff like a power balance test you can run with a scanner that monitors undetectable RPM deviations when each cylinder fires in order to give comparative cylinder power contributions to communicate the same information as a compression test.
Nifty stuff, computers.
Well, in an ideal world at least. When they pulled the misfire code on my celica before I bought it, the mechanic wanted to change the O2 sensors. Like I said...if you know what youre doing and use car forums and other resources, you might be able to do more with the code than they can in certain cases. I know what youre saying though.
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