• We’re currently investigating an issue related to the forum theme and styling that is impacting page layout and visual formatting. The problem has been identified, and we are actively working on a resolution. There is no impact to user data or functionality, this is strictly a front-end display issue. We’ll post an update once the fix has been deployed. Thanks for your patience while we get this sorted.

Engine check light, how do I turn it off and why does it go off?

Page 2 - Seeking answers? Join the AnandTech community: where nearly half-a-million members share solutions and discuss the latest tech.
Ok right the next day after my post, about 10 miles or so, the light went off. First thing I did was readjust the gas cap. (It was on as normal the last time I filled up.) and it went on the day before as I was on my way home from work.

However, I will keep the advices here in mind just in case. Should I still be worried?

Originally posted by: Pacfanweb
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.
Click to expand...

Its like knowing what the symptom is but the symptom could be caused by anything related to said symptom. And you have to know how the mechanics work to generate the symptoms that does show up. Am I on a tangent with your post?
 
Originally posted by: Imaginer
Ok right the next day after my post, about 10 miles or so, the light went off. First thing I did was readjust the gas cap. (It was on as normal the last time I filled up.) and it went on the day before as I was on my way home from work.

However, I will keep the advices here in mind just in case. Should I still be worried?

Originally posted by: Pacfanweb
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.
Click to expand...

Its like knowing what the symptom is but the symptom could be caused by anything related to said symptom. And you have to know how the mechanics work to generate the symptoms that does show up. Am I on a tangent with your post?
Click to expand...
Yes. Certain cars are bad about getting a code that tells you "EGR has insufficient flow". So what the Autozone and lesser independent shop guys do is recommend either the EGR valve, EGR sensor, or both.
Neither of which, on said car, are the problem....the problem is, it actually DOES have insufficient or even no flow. The ports clog up. Dealership techs and sharp independents will know this, and recommend the appropriate repair.
Parts boys and less-competent independents will start off with the basics...sell the sensor, valve, and recommend tune up, injector flush, etc. And while you're at it, when's the last time you flushed your tranny? And so on.

The right way to do this, and a honest and competent mechanic will do it, is first recommend the repair that's actually going to fix the problem it was in service for. Then you can recommend any needed maintenance or other repairs that might need to be done.

So can you simply get the code, replace whatever sensor triggers that code, and actually fix your car? Sometimes. But that's more blind luck than anything else.
 
depends some of the codes are very obvious. I had my light come on, went to Auto Zone they gave me the little computer I hooked it up, got the code. they checked it and it was from a faulty O2 Sensor. Was the sensor actually bad? I don't know as my car wasn't running rich, but replacing an O2 Sensor is pretty cheap and can be done yourself. Of course not all codes are so obvious. BTW I still haven't replaced my O2 Sensor and it's still not running rich. And my milage isn't dropping. (I drive very little) I plan to fix it this weekend maybe, the fact they rent tools will make it a snap for me.
 
Originally posted by: QueBert
depends some of the codes are very obvious. I had my light come on, went to Auto Zone they gave me the little computer I hooked it up, got the code. they checked it and it was from a faulty O2 Sensor. Was the sensor actually bad? I don't know as my car wasn't running rich, but replacing an O2 Sensor is pretty cheap and can be done yourself. Of course not all codes are so obvious. BTW I still haven't replaced my O2 Sensor and it's still not running rich. And my milage isn't dropping. (I drive very little) I plan to fix it this weekend maybe, the fact they rent tools will make it a snap for me.
Click to expand...
You can't always tell if the car is running rich...and BTW, a bad O2 sensor can tell you you're running rich or lean. OBDII systems are VERY sensitive, and it doesn't take much of a vacuum leak or a legitimate lean/rich condition to turn the light on.

What a GOOD shop will have is a computer to actually monitor all the sensors while running, to determine if they're all in range.
An Autozone has no idea what they are supposed to be reading at any given time.
 
Just to iliderate previous posts. o2 sensors don't even have to be that bad to set off codes. They could just be getting "lazy" we used to call them. They just wouldn't work as fast as they should to tell the computer what to do for lean/rich condition and would cause weird drivability issues.
 
Originally posted by: Pacfanweb
Originally posted by: Imaginer
2001 Ranger XLT

So any Autozone can tell me the codes of what is wrong for free?
Click to expand...
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.
Click to expand...

Who ever said it would "diagnose" the problem. The codes simply let you know a sensor has "tripped". This can be very beneficial in diagnosing the problem or it can be a wild goose chase. I've heard enough horror stories from shops where the codes left the service technician on a similar wild goose chase...so taking it somewhere doesn't not necessarily diagnose it either.

It is worth going to Autozone so you can find out what codes have tripped so that you can educate yourself on the problem. Then when you take it somewhere to be fixed, you'll have a better starting point to discuss the problem with the technician.
 
With some cars you can simply get the codes right from the car. My stratus would display the numbers where the odometer was (if I turned the key to Off->On repeatedly). My talon would flash like morse code (if I remember correctly). My Nissan has a trouble shooting center thing as part of it's smart computer options if I remember correctly (never had to use it).
 
My CEL came on in the Focus yesterday, I stopped in to Autozone to get the code pulled.

Minor Evaporative Emissions leak.

I just wanted to know that it wasn't anything serious. Off to tighten my gas cap and disconnect the battery for a minute. 😉
 
Could be some hidden problem waiting to burst out. My family's POS car started off it's "trials and tribulations" with a check engine light coming on after a half hour or so of driving. For a month or so, no visible problems. Then it started losing power... After a few more weeks, the engine would cut out or the car would be unable to go more than 20kph on a very very light incline. A year or so later, the light comes on after 20 minutes, the engine starts sputtering at stops, and can go a whole 15kph on an incline...
 
If you are keeping the vehicle get the Service Manuals and then get a scantool with bi-directional control in the price range you can afford, in the long term you will save a lot of money.





 
You must log in or register to reply here.

TRENDING THREADS

Back
Top