Meaning of Check Engine Light?

Hi. Is there a list somewhere that tells all of the reasons that the Check Engine Light might come on? The last time it came on ('92 EB) I found that the power steering fluid level was low. I filled it and the check engine light went off. Coincidence?

I found information about how to get the test codes but sometimes it might be something really simple that would not require meters and deciphering.

My timing chain is apparently loose which probably is affecting the timing and that might be why my check engine light is on, but at the moment I am forced because of dirt road conditions to drive my Explorer a couple of miles a day and risk the chain breaking. It's either that or my kids can walk home 2 miles in the rain and mud or I can get stuck with my '78 F350.

Also, in case everyone doesn't know it Auto Zone has troubleshooting and repair information on their web site

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Not only did they have the timing parts I needed but had step by step repair instrucitons with photos. They also seem to have recall notifications etc.

Thanks.

Reply to
Ulysses
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Check engine light and low PS fluid level???? About a big a coincidence as you could hope for.

As far as repairing a malfunction that illuminates the MIL without knowing the code and the proper diagnostic tree for that code....." my computer doesn't work... how do I fix it?"....... Your computer is trying very hard to give you information yet you don't want it...... the word goofy comes to mind.

I can't ever recall seeing any timing chain concerns with the OHV 4.0 but (somehow) you know the chain is loose and find it grand that AutoZone has parts that you really have yet to prove to yourself that you need.

If it is all as easy as you assume, why am I still employed?

Reply to
Jim Warman

On my 94 it means "emissions control problem".

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Reply to
SmartyPants

According to my Hayne's Manual there is a sensor for the power steering pressure. I don't know if this particular sensor will activate the "Check Engine" light. Apparently you know but don't know how to give a direct answer.

OK, you can call me goofy. This a a risk we all take when we post on newsgroups. There may be somebody out there who has very little useful information to contribute but a very high opinion of themselves and wants the world to know how wonderful they are.

Meanwhile, I found the list of trouble codes easily enough but I was thinking there may be a short list of problems that actually cause the "Check Engine" light to come on. I do not know if all of the codes cause the warning light to come on. I'm trying to find out. It may be that there are things that cause it to come on that I can easily check.

We are only talking about $60 here. I'll bet you get that much from your customer(s) for a quart of oil. I don't know how you go about diagnosing a problem. Do you take the entire engine apart to find out if it needs new spark plug wires?

This newsgroup is filled with people who have actual, practical working experience that have discovered how to fix many problems on Explorers and are willing to share their knowledge with other Explorer owners. I guess you are not one of them.

For posterity (cause I'm sure you don't care) the symptoms my engine is having is pinging upon acceleration and a metallic rattle that is not consitant with engine speed. The rattle still exists with the serpentine belt removed. The only engine component that I can think of that could cause such a situation is the timing chain. I will post my results so in a few months when somebody else has a similar problem they can do a Google search, find my post, and decide for themselves if they have the same problem.

You are still employed because your typical motorist of today is not willing to research the problem, find the parts, open the hood, remove the radiator, remove the belt, remove the water pump, remove the pully, remove the timing chain cover, and replace the chain. How much do you get for such a job? $1000? $1500? Most people would take a $3000 car to the junk yard rather than spend that kind of money on it.

deciphering.

Reply to
Ulysses

Thanks.

Reply to
Ulysses

Yes... it is for power steering PRESSURE. It tells the PCM that the pump is adding load to the motor and the PCM increases the idle speed. The only time this switch is "tested" by the PCM on this year is during the dynamic response portion of the KOER test. If the fluid level is low enough to show this problem you would a whole pile of physical stimuli long before any code generation could occur.

As for the balance of my response I thought I went above and beyond the call of duty and offered up some good info. And we can even take it a little further. Depending on year, make and model, some codes will not turn off the CEL until the code is cleared (and the CEL will reset if the original problem remains unfixed). Some codes require the problem to occur on consecutive drive cycles. Some codes require multiple instances - some on the same drive cycle, some on consecutive drive cycles.

On OBD2 Fords, misfire codes will not set if the "misfire profile" hasn't been learned. Yes, there are many "pattern" failures that will set the CEL - ask anyone that has been on the receiving end of good ol' P0401 (the infamous DPFE sensor)... but it remains that the code needs to be known before anyone can hope to address the concern.

BTW.... this is all free so I get to be any way I choose. You will also have to realize that much of my employment is derived from DIYers that wont listen to advice and make a complete "c*ck up" of it. Some days I'm terse... some days I'm playful and some days I'm facetious - feel free to add me to your killfile...

instrucitons

Reply to
Jim Warman

Thanks. I just want to say, just so you'll understand, that I usually research everything I can find before I ask questions on newsgroups. If I have a problem with my car I make every attempt to solve the problem or find the answer elsewhere first. Maybe I sound like an idiot, and maybe I am, but as long as I get the information I need to fix my car I don't really care if someone calls me "goofy" or worse.

All my Explorer Handbook says is that the check engine light is for the emissions system. Well, a lot of factors effect the emissions so that could mean a lot of things. And since there are sensors all over the place under the hood I though some of them might trigger the CEL.

. If the fluid level is low enough to show

This is what I wanted to find out. For all I knew the check engine light would come on if a taillight burned out. Ford and Hayne's don't seem to supply specifically what it means. They just say "have your car serviced as soon as possible." They also say that if it comes on then goes off "don't worry about it." Hmmm.... If it keeps coming on and going off then I would worry. At that point I would get out the voltmeter and read the codes. But if something like low power steering fluid could have caused it then pouring in some goop is a lot easier than reading codes.

You will also have

I freely admit that I am not by any definition an "auto mechanic" unless shadetree or backyard types qualify for that. I know enough to know that there are things I don't know that are not in the books that experienced mechanics all know. Know what I mean? So maybe I ask some real dumb questions sometimes but so far the result has been that I learn enough to not "c*ck up" anything so bad that I can't undo it. Besides, my truck is worth so little now that about all I have to lose is some time and a few bucks worth of parts.

Reply to
Ulysses

I put myself in the same category as you, Ulysses. In my experience with the CEL, my GUESS is that it is caused by the "good ol' P0401 (the infamous DPFE sensor)" as Jim calls it. BTW, don't try to get the vehicle smog checked in Calif with that CEL activated. DMV computers are programmed to

*assume* its lit up due to an emission problem, such as clogged catalytic converter, and your vehicle will FAIL the smog test. Test stations generally won't tell you this beforehand. They'll just run the test, let you fail, then say get it fixed and come back to pay for the test all over again! Sweet deal, huh?
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DAVMO

Reply to
Big Shoe

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