automotive questions

Lathum · 08-01-2005, 10:46 PM

So the check engine light in my truck came on a few weeks ago, I was a little worried but it seemed to be running fine. So then the light went off on it's own. A buddy of mine said he thinks that light may come on after a certain amount of miles. Anyone know anything about this sort of thing?

Airhog · 08-01-2005, 11:27 PM

The main problem is that many different sensors tie into that one light. So any number of problems could have caused the light to come on. I have seen cars that ran fine, but had the same problem you describe, with the light coming on every once in awhile.

The only way to know what is wrong with your truck, which I am assuming is a newer model, is to read the error codes from the computer. If you had an older model truck, you can actually get the computer to show you the error codes through the engine lamp. You will need a manual though.

If you have a newer model truck, say from 94 or 95, then you will need to either take it to a shop to get the codes read, or try a place like autozone. If a part failed intermittenly, the error code should be stored in the computer still.

Swaggs · 08-02-2005, 12:26 AM

Hondas do this as a reminder at certain mileage points to have your car serviced or oil changed. You do some type of ritual where you hold in the mileage reset button while starting up the vehicle and hold it in for like 10 seconds and it turns off.

Rizon · 08-02-2005, 01:46 AM

Quote:

Originally Posted by Airhog

The main problem is that many different sensors tie into that one light. So any number of problems could have caused the light to come on. I have seen cars that ran fine, but had the same problem you describe, with the light coming on every once in awhile.

The only way to know what is wrong with your truck, which I am assuming is a newer model, is to read the error codes from the computer. If you had an older model truck, you can actually get the computer to show you the error codes through the engine lamp. You will need a manual though.

If you have a newer model truck, say from 94 or 95, then you will need to either take it to a shop to get the codes read, or try a place like autozone. If a part failed intermittenly, the error code should be stored in the computer still.

Bingo.

Or just do what I do. Put a piece of tape over it and it's fixed.

(Ok, so I stole that from the Simpson's, but I really do it)

Airhog · 08-02-2005, 07:44 AM

Personally, I think its worth driving down to autozone and having them check the code for you. If there is a problem with your engine, you want to catch it early, before it becaomes a 1500$ headache.

cartman · 08-02-2005, 08:36 AM

Also, the check engine light is used for much, much more than the engine. It also alerts to problems with the exhaust, transmission, and sometimes even the general electrical system.

Wasabiak · 08-02-2005, 10:04 AM

It would have helped to know the year, make and model, but I'm going to make an educated guess based on your symptom and say that at one point, your fuel filler cap was loose, which probably set a code P0440 or P0442 (If it's a Ford, it might even be a P0456). This is a gross evaporative emission system leak (greater than .040"). If the cap has since been installed properly, and tight, then after a few drive cycles the PCM would see that the leak has been fixed, and thus would turn the light off.

This, of course, all depends on the year, make and model of the vehicle. I don't have enough info to pinpoint it. Let me know if you need any help. Don't pay someone lots of $$$$$$ to look into this. I'm here for you bro. =)

Todd

rkmsuf · 08-02-2005, 10:12 AM

Do you drive sans underwear?

Bee · 08-02-2005, 10:31 AM

Just so you know, taking it in to have mechanics look at it may not work either. My uncle took his car in several times and they kept replacing different sensors and finally the mechanic told him the only solution they had was to unhook the light from the dash. (This was all under warranty and at the dealership, so they weren't trying to take him for money). This became somewhat of a running joke in my family, whenever anything went wrong we always suggest unhooking the sensor.

Wasabiak · 08-02-2005, 01:56 PM

That's the most ridiculous thing I've ever hear. No dealership with any cred would do such a thing.

I used to work at a Lincoln dealer where the owner went to auctions and bought RAV's (reacquired vehicles). They were mostly lemon law cars and stuff like that. Then he'd have them delivered to the dealer, and we, as techs, would have to fix them so he could turn around and sell them for an incredible profit. So I've seen some pretty weird shit happen on cars (Wiring harnesses, RF interference, water damage, etc.) I never EVER had to unhook a warning light or anything like that. Needless to say, I do not work for that slimey, money hungry prick anymore. I now work at a very reputable Subaru dealer just across the street.

BTW, if anyone is in the market for a car, Subaru makes the best cars on the road IMO.

/shameless plug

Lathum · 08-02-2005, 03:50 PM

My truck is a 97 explorer. Thx for the info guys

Wasabiak · 08-02-2005, 04:17 PM

Quote:

Originally Posted by Lathum

My truck is a 97 explorer. Thx for the info guys

4.0L or 5.0L? If it's a 4.0L V6, it could also be a DPFE sensor (Delta Pressure Feedback Exhaust). Ford had problems with this particular sensor getting water/condensation contamination and setting a code P0401 or P1401. Just an FYI.

08-01-2005, 11:27 PM	#2
Airhog Captain Obvious Join Date: Aug 2001 Location: Norman, Oklahoma	The main problem is that many different sensors tie into that one light. So any number of problems could have caused the light to come on. I have seen cars that ran fine, but had the same problem you describe, with the light coming on every once in awhile. The only way to know what is wrong with your truck, which I am assuming is a newer model, is to read the error codes from the computer. If you had an older model truck, you can actually get the computer to show you the error codes through the engine lamp. You will need a manual though. If you have a newer model truck, say from 94 or 95, then you will need to either take it to a shop to get the codes read, or try a place like autozone. If a part failed intermittenly, the error code should be stored in the computer still. __________________ Thread Killer extraordinaire Yay! its football season once again!

08-02-2005, 12:26 AM	#3
Swaggs Coordinator Join Date: Oct 2000	Hondas do this as a reminder at certain mileage points to have your car serviced or oil changed. You do some type of ritual where you hold in the mileage reset button while starting up the vehicle and hold it in for like 10 seconds and it turns off. __________________ DOWN WITH HATTRICK!!! The RWBL Are you reading In The Bleachers?

08-02-2005, 07:44 AM	#5
Airhog Captain Obvious Join Date: Aug 2001 Location: Norman, Oklahoma	Personally, I think its worth driving down to autozone and having them check the code for you. If there is a problem with your engine, you want to catch it early, before it becaomes a 1500$ headache. __________________ Thread Killer extraordinaire Yay! its football season once again!

08-02-2005, 08:36 AM	#6
cartman Death Herald Join Date: Nov 2000 Location: Le stelle la notte sono grandi e luminose nel cuore profondo del Texas	Also, the check engine light is used for much, much more than the engine. It also alerts to problems with the exhaust, transmission, and sometimes even the general electrical system. __________________ Thinkin' of a master plan 'Cuz ain't nuthin' but sweat inside my hand So I dig into my pocket, all my money is spent So I dig deeper but still comin' up with lint

08-02-2005, 10:12 AM	#8
rkmsuf Head Coach Join Date: Dec 2001	Do you drive sans underwear? __________________ "Don't you have homes?" -- Judge Smales

08-02-2005, 10:04 AM	#7
Wasabiak High School Varsity Join Date: Jul 2002 Location: Beulah, ND	It would have helped to know the year, make and model, but I'm going to make an educated guess based on your symptom and say that at one point, your fuel filler cap was loose, which probably set a code P0440 or P0442 (If it's a Ford, it might even be a P0456). This is a gross evaporative emission system leak (greater than .040"). If the cap has since been installed properly, and tight, then after a few drive cycles the PCM would see that the leak has been fixed, and thus would turn the light off. This, of course, all depends on the year, make and model of the vehicle. I don't have enough info to pinpoint it. Let me know if you need any help. Don't pay someone lots of $$$$$$ to look into this. I'm here for you bro. =) Todd

08-02-2005, 10:31 AM	#9
Bee Pro Starter Join Date: Oct 2000 Location: Fairfax, VA	Just so you know, taking it in to have mechanics look at it may not work either. My uncle took his car in several times and they kept replacing different sensors and finally the mechanic told him the only solution they had was to unhook the light from the dash. (This was all under warranty and at the dealership, so they weren't trying to take him for money). This became somewhat of a running joke in my family, whenever anything went wrong we always suggest unhooking the sensor.

08-02-2005, 01:56 PM	#10
Wasabiak High School Varsity Join Date: Jul 2002 Location: Beulah, ND	That's the most ridiculous thing I've ever hear. No dealership with any cred would do such a thing. I used to work at a Lincoln dealer where the owner went to auctions and bought RAV's (reacquired vehicles). They were mostly lemon law cars and stuff like that. Then he'd have them delivered to the dealer, and we, as techs, would have to fix them so he could turn around and sell them for an incredible profit. So I've seen some pretty weird shit happen on cars (Wiring harnesses, RF interference, water damage, etc.) I never EVER had to unhook a warning light or anything like that. Needless to say, I do not work for that slimey, money hungry prick anymore. I now work at a very reputable Subaru dealer just across the street. BTW, if anyone is in the market for a car, Subaru makes the best cars on the road IMO. /shameless plug

08-02-2005, 03:50 PM	#11
Lathum Favored Bitch #1 Join Date: Dec 2001 Location: homeless in NJ	My truck is a 97 explorer. Thx for the info guys

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