Car trouble? Check engine light wont go off.

BlindedByTheLite

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the light is a constant on, not blinking.

i accredited this to me driving thru a huge snow drift and the steady -25ºF below the past 3 nights. i figured i had a bunch of snow in the engine or something. could the cold weather keep the engine from drying out or do you suspect it's something else?

how many things can cause the check engine light to come on and stay @ a constant on? i just don't wanna take my car in and have to pay a bunch of money for them to hook it up to their diagnostic equipment just to find out if i waited a couple weeks it'd have gone away on its own.

whatcha think?

/ubbthreads/images/graemlins/help.gif /ubbthreads/images/graemlins/icon11.gif
 

raggie33

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ive heard of some companys who have that light come on at a certain milage but im not to up on this stuff
 

iddibhai

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drive thru snowdrift? maybe the O2 sensor wire came off or became loose. check under the car, ahead and behind the cat. conv. to see if wire to O2 sensor is ok. or it might be too cold for the o2 sensor to light up (which, depending on the car, is either heated by exhaust gas or internal heater; the former will have a hard time warming up in such conditions).

the easy one, of course: did you check the gas cap is on tight till it clicks? any loose vac. hoses underhood that got knocked when you hit the snow drift?
 

LukeK

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FYI, Autozone will check the code that the car computer is putting out and tell you the probable cause for free.
 

greenLED

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The light on my car comes and goes and nobody's been able to diagnose what the problem is or turn it off for good. I've gotten used to it now. Unless it flashes or it annoys you, I wouldn't worry too much.
 

Minjin

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Get the code at a local auto parts store. Then come back here and tell us what the code said and we'll advise you. Or you can just take it to the dealer... /ubbthreads/images/graemlins/wink.gif

Mark
 

LifeNRA

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[ QUOTE ]
raggie33 said:
ive heard of some companys who have that light come on at a certain milage but im not to up on this stuff

[/ QUOTE ]
This is true. Sometimes it is even stated in the owners manual.

Our vans check engine light came on a few months ago. My wife said she had gotten gas at a different station that week. She was sure it was the gas but I was not so sure myself. I had never heard of a check engine light coming on because of changing brands of gas. Well she used up most of the gas and then refilled at the normal place and the light went off that same day. Has not been back on since. I guess I should listen to my wife more /ubbthreads/images/graemlins/blush.gif.
 

turbodog

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disconnect the battery for several hours..... that should clear the computer and make the light go off

if it was an one-time occurrence then the light should stay off, if not....... oh well


for what it's worth..... you know that my lawn mower has a check engine light!
 

mattheww50

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No limit to the things that it can be. On many cars, once the light comes on, it stays on until cleared. One of the great frustrations in fixing cars was fixing problems that were not easily reproducable, and the Industry responded by having the engine control computer latch up these error codes in a non-volatile memory, and leaving the check engine light on to tell a technician that there either is a problem, or has been one that has been latched up. In early versions, these were lost once the ignition was turned off, although the dealer could install a jumper to keep the computer memory power on so they wouldn't be lost. I had a Mercury Mystique where it came on. It turned out the computer was occaisionally losing the input from the crankshaft position sensor.

You need to take the vehicle to someone who can read out the code, and reset it. Depending upon what it is and how many times it has occured, you may have to do something, or you may be able to ignore it. With my car, since it didn't cause misfiring, overheating, or any noticeable impact, I knew there wasn't any hurry to do something. Took me a couple weeks to get it in. They read out the code, the car was still under warranty, and they simply replaced the sensor. The extreme weather may have created one or more out of expected tolerance conditions, which actually requires no remedial action.

Oh yes, and BMW's used to do it at 30,000 miles to indicate the need for a specific emission control service. The way it was turned off (according to the factory service manual) was to remove the little light bulb (I used to own a 5 series)...
 

Draco_Americanus

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[ QUOTE ]
LifeNRA said:
[ QUOTE ]
raggie33 said:
ive heard of some companys who have that light come on at a certain milage but im not to up on this stuff

[/ QUOTE ]
This is true. Sometimes it is even stated in the owners manual.

Our vans check engine light came on a few months ago. My wife said she had gotten gas at a different station that week. She was sure it was the gas but I was not so sure myself. I had never heard of a check engine light coming on because of changing brands of gas. Well she used up most of the gas and then refilled at the normal place and the light went off that same day. Has not been back on since. I guess I should listen to my wife more /ubbthreads/images/graemlins/blush.gif.

[/ QUOTE ]

She could have left the gas cap on lose, that will cause the service engine soon light to come on.
 

Draco_Americanus

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[ QUOTE ]
greenLED said:
The light on my car comes and goes and nobody's been able to diagnose what the problem is or turn it off for good. I've gotten used to it now. Unless it flashes or it annoys you, I wouldn't worry too much.

[/ QUOTE ]

Personaly I would find a diffrent mechanic then. The service engine soon light can come on for many many diffrent reasons. You need to know what the car is telling you before you can decide to ignore it and not have futher repairs and or damage to your vehical.
I learned the hard way, some mechanic did not wish to bother fix My truck right and I followed his advice, untill My catalytic coverter failed and cloged. It was the O2 sensor the whole time, it was interminit but still killed the coverter. I also got better mpg after a new O2 sensor too!
 

mapson

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Jul 25, 2004
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So far, I know of two simple reasons the engine light may come on and they have been stated above.

1. Due for maintenance.

2. Loose gas cap after fillup.

Look into those two before a trip to the dealer. For the maintenance one, usually the manual will have a page on how to reset the light. For the gap cap, just rescrew until you hear several clicks.
 

BIGIRON

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It could be, literally, dozens of things -- some as simple as overfilling the fuel tank (no joke) to an impending explosion. Most major auto parts stores and independent garages can quickly read the code for a small or no charge. You really should consider having it checkd out. Replacing a O2 sensor for a few $$ might save you a catalytic converter and EGR valve at like $400.
 

LifeNRA

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[ QUOTE ]
Draco_Americanus said:

She could have left the gas cap on lose, that will cause the service engine soon light to come on.

[/ QUOTE ]
Actually I checked the gas cap and made sure it was tight. Maybe the gas had water in it? Not sure really. /ubbthreads/images/graemlins/confused.gif
 

BIGIRON

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Coincidence. Just received a Harbor Freight sale flyer advertising a universal code reader for $39.99. Check their website for part # 46030. This is a very basic unit, but should give you the code readout and, surely the dealer will tell you what the code represents.
 

eluminator

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Apparently it's difficult to see the trouble codes on most cars. Why is that?. My 1994 Plymouth makes it easy. Just turn the key on 3 times in 5 seconds and the check engine light blinks the codes. Why don't all cars do this?
 

markdi

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if what ever is wrong causes the car to run really lean
catalytic converter and valves-pistons could be damaged if you run the engine at sustained high speed on the freeway.

- freeway driving is high speed compared to around town driving.

a friend of mine had the carpet in his car catch fire from a glowing red hot catalydic converter.
 
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