"Service Engine Soon" light is on, need advice.

[JohnCU]

I filled up my car last week and I am pretty sure that I tightened on the cap correctly, but a day after this my "Service Engine Soon" light came on. This is not the first time this has happened after I filled up with gas. There is a label on my gas cap that says the light may come on if you do not tighten the cap fully. So, the last time this happened, I took it to the dealer and he plugged it into the computer and said it was just a fluke or something.

So now, the light is on again. It isn't on in the morning when I start up, but in the afternoon it comes on when I start up. The car is running fine and I don't want to take it to the dealer, is there anyway I can get it to go off?

 

[Hayabusa Rider]

What kind of car?

 

[AreaCode707]

*ear out for the answer* My car's service engine light is on too, and I recently got the oil changed and stuff.

 

[JohnCU]

1997 Chevy Lumina.

 

[Jzero]

What kind of cars, dangit???

 

[Hayabusa Rider]

You need to have it reset, but computers can be found at service stations, so you don't have to go to a dealer and pay big bux. If you are friendly with any gas station owners who service cars, it is no problem. Usually this happens when you don't tighten the cap enough or if you try to fill the tank while it is running. I don't know about Luminas, but this is true for late model VW's. It may be a bad sensor too. In any case, have it taken care of in case something bad really does happen.

 

[RSMemphis]

You can reset the engine chip quite easily yourself by unplugging the battery. Well, at least it works for Fords...

 

[AreaCode707]

mine's a 00 Pontiac Grand Prix ??

 

[ShallowHal]

One small piece of electrical tape will fix that annoying light.

 

[fastz28]

<< *ear out for the answer* My car's service engine light is on too, and I recently got the oil changed and stuff. >>



On newer vehicles, you need to reset the computer after oil change. Read the manual on how.

 

[Jfrag Teh Foul]

Sometimes it can be the O2 sensor on the exhaust going bad. I have had that happen to me two times on seperate vehicles.

 

[Pacfanweb]

First of all....don't overfill the tank. When it clicks off by itself, don't run another buck-fifty or whatever you can squeeze in there. That can cause the problem also.

Are you sure the cap is sealing properly? Take it off and see if the o-ring is twisted or cut.

To reset the computer, you can remove the negative battery cable for a few minutes, then reinstall. That resets everything.

If the light comes back on soon after, you have a genuine fault and it needs to go into the shop to diagnose properly.
Myself, and others here can tell you different sensors it COULD be all day long, but guessing doesn't usually work.

 

[flot]

Someone please tell me what sensor exactly it is that gets triggered if you don't close the gas cap?!?

I always fill up my car with it running (don't try to tell me that it's a bad idea unless you have some factual proof), and I went to do the same in my girlfriends car (an 00 mazda) and she freaked out and told me the same story, she did that once and had to take it back to the dealer to reset the light...

I assume it's some nonsense emissions thing, but what exactly is the sensor for and what is triggering it, just the lack of a pressurized fuel system??

 

[walrus]

THe light on my honda 2001 Civic can be reset by pushing in the odometer trip reset button for 5 sec.

 

[lepper boy]

I am very familiar with this problem.. 1st to find out what it means, you really need to get someone with a computer to plug in and talk to the computer and see what it says is wrong. Or how many miles do you have on it? I know my wifes Honda Accord, Has a engine light that comes on every 7500 miles. But you can reset it manually using the odomoter controls.. look in your book and see if it has someway to reset it manually. Or as was mentioned about you can unhook your batterty for a few minutes then hook it back up... and bang, your ready to go....

 

[GrumpyMan]

My check engine light has been on for 7 years, maybe I should have it looked at when the van hits 200,000 miles. :Q

 

[wyvrn]

I can reset my Honda's by inserting the key into the slot on the odometer. Sometimes the dealer forgets to do this and the red light stays on.

 

[Gonad the Barbarian]

Leave the battery unhooked for 30 minutes. Hook it back up and if the light is still on or comes back on take it in.

 

[desertdweller]

<< Someone please tell me what sensor exactly it is that gets triggered if you don't close the gas cap?!?

I always fill up my car with it running (don't try to tell me that it's a bad idea unless you have some factual proof), and I went to do the same in my girlfriends car (an 00 mazda) and she freaked out and told me the same story, she did that once and had to take it back to the dealer to reset the light...

I assume it's some nonsense emissions thing, but what exactly is the sensor for and what is triggering it, just the lack of a pressurized fuel system?? >>




It is an emmisions thing, because what most people don't know is that raw fuel vapors are alot of the cause of
air polution in big cities. Thats why in a lot of places they have those things on the nozzle at the gas pump, to keep
those vapors out of the air.

What your car does is to pressurize the fuel vapor recovery system with a couple of PSI and test to see how long it
stays pressurized. If it looses pressure it sets an engine code and turns on the Check Engine light. The fuel vapor
recovery system goes from the fuel tank to a canister and to the engine with some other lines going to a pump. This is
only on newer cars. Thats how leaving the gas cap loose will set the check engine light.


DD

 

[ucdnam]

For those with Honda Accords, this guy's light is equivalent to a service light, not the maintenance required one. There's a difference because you can turn off the maintenance one yourself and it tells you how in the manual, while the service one is possible due to some malfunction or other "bad" problems. I've never read on how to turn that one off and I know that the dealers in the Sacramento area actually charge like 40 bucks to turn it off if you initiated it by not turning your gas cap atleast 3 clicks.

 

[LAUST]

Isn't ODB2 great :disgust:

You can reset the engine chip quite easily yourself by unplugging the battery. Well, at least it works for Fords

On the GM's to reset the computer it's with the ECM fuses, they are usually pretty similar

 

[Pacfanweb]

<< Someone please tell me what sensor exactly it is that gets triggered if you don't close the gas cap?!?


On Fords it's called the FTP sensor....fuel tank pressure.....the tank is a sealed unit that has vacuum applied to it at times to pull the vapor into the engine and burn it.
Gas vapor is a hydrocarbon, and therefore pollution.

On a Ford, if you leave the gas cap off you'll get a code PO455 which means gross air leak in the evap. system. I can't tell you how many people I've walked out to the car with and found the cap loose.

 

[Hayabusa Rider]

Now this is interesting. I was told that on my car, the memory is non-volatile. I would hate to clear out the memory before the codes were checked.

 

[LAUST]

<< Now this is interesting. I was told that on my car, the memory is non-volatile. I would hate to clear out the memory before the codes were checked. >>


If it's an actual problem the trouble code will come right back, when I don't have my secondary computer plugged in my system goes nuts from the blower, you clear it, boom right back. but if it's a problem like the gas cap and you fix the problem it's no big deal.

After you clear the ECM your vehicle will run funny for the 1st few minutes as it calibrates for the Fuel and Air density, in that process it'll also rediscover any real problem you might have.