Can anyone tell me why my Check Engine Light (CEL) just came on?

[potator]

I've got an 02 EP with about 9,600 miles on it right now. I've been doing everything regular, oil changes at 3,000 miles, etc. My car is bone stock except for my Magnaflow Cat-back exhaust system. Absolutey no other mods. I got my Magnaflow a few months ago - I think late 2003 or early 2004. I've had no problems since, car ran great, never felt weird, or smelled weird whatsoever. But today, driving back home on the freeway, I noticed my Check Engine Light just came on. I know for a fact it wasn't there when I left my house. So it came on anywhere from the time I started my car to leave and go back home, to the time I noticed it on the freeway. Even now, my car feels absolutely normal, runs perfect, can't tell a single difference, besides the light. I haven't resetted my ECU when installing the Magnaflow. Can anybody tell me why my CEL came on, and what I should do?

[4g63dsm]

your exhaust should give you a CEL even if you didn't reset your ecu,because all the sensors are earlier in the pipe. Just take it in to honda and it should be covered under warranty.

[Civicvtec1ps]

Aftermarket exhaust shouldn't even give you CEL.
Just lift up your car and check O2 censor.
Reset ECU by pulling out ECU fuse.
It should be good.

[potator]

Thanks for the replies, and by the way, I just checked in my owners manual about the light, and in the book they call it the "Malfunction Indicator Light", correct? Is this the same as the "Check Engine Light" everyone seems to call it here? Because I don't see another light in the manual called the Check Engine Light.

[oogy-boogy]

Originally posted by Civicvtec1ps
Aftermarket exhaust shouldn't even give you CEL.
Just lift up your car and check O2 censor.
Reset ECU by pulling out ECU fuse.
It should be good.

Exactly....exhaust will not cause you to throw a cel unless you play with the cat (remove/replace, etc).

Hit up the local Auto Zone as they will do a free scan and let you know what code you're throwing.

[dc5-K20A3]

check to make sure your gas cap is tightened properly. My check engine light came on once because of this. Once you tighten it, it should go away after a couple of driving trips

[the JigGa mAn]

Originally posted by Civicvtec1ps
Aftermarket exhaust shouldn't even give you CEL.
Just lift up your car and check O2 censor.
Reset ECU by pulling out ECU fuse.
It should be good.


thats what i was thinkin maybe an o2 sensor problem...

[glw]

Originally posted by dc5-K20A3
check to make sure your gas cap is tightened properly. My check engine light came on once because of this. Once you tighten it, it should go away after a couple of driving trips also check the oil level...

[potator]

Thanks for the replies, I just checked my oil level and it's fine. I've gotten an oil change about 1,600 miles ago. I just took off and retightened the gas cap too. I haven't looked under the car yet. I'll drive around today and see if this light goes away. And can someone explain to me what exactly is 'running rich'?

[oogy-boogy]

Originally posted by potator
Thanks for the replies, I just checked my oil level and it's fine. I've gotten an oil change about 1,600 miles ago. I just took off and retightened the gas cap too. I haven't looked under the car yet. I'll drive around today and see if this light goes away. And can someone explain to me what exactly is 'running rich'?

Why not just go to Autozone and have them hook it up to a reader for free?

[younggotti266]

Originally posted by potator
Thanks for the replies, and by the way, I just checked in my owners manual about the light, and in the book they call it the "Malfunction Indicator Light", correct? Is this the same as the "Check Engine Light" everyone seems to call it here? Because I don't see another light in the manual called the Check Engine Light.

MIL = CEL

Same shit

Manufacturers are now calling them Malfunction Indicator Light(MIL)

[Kal]

running rich is when you have excess fuel squirting to your combuston chamber. usually using a vafc and leaning it out will result in some gains.

[cpu519]

I ran over some debris and it hit the O2 sensor wiring and pulled one wire slightly out of the connector, that caused a CEL. I pushed the wire back and it fixed the problem. Check to see that all the wires on both sensors are completely pushed into the connectors. Maybe you didn't notice you ran over something.

[chunky]

do NOT reset the code w/o first checking it. it is probably a catalyst operating below threshold efficency or other o2/catalyst code, but it could be something else, and wouldn't you want to know for sure?

when I get home from work tonight, I'll link you to a page that shows how to read the CEL by jumping two pins on the obd II connector.

[potator]

Ok, I don't really know why, but yesterday after I filled up my car with a full tank of 91 octane Chevron (what I always use), the light just suddenly went away. I guess this is bitter-sweet, because I'm *assuming* whatever problem it may have been is now gone. But at the same time, I don't know what the problem was. During the time my CEL came on, I had about 1/4 tank left of gas. And the car seemed to have been wasting more gas that time too, or it may have just been my head messing with me. But yesterday was the first time I filled up after I got the CEL (which is 1 day after), and it just went away. The gas mileage seems to be perfectly normal too. Could it have just been bad gas that was in the tank before? It may seem a bit far stretched but the gas I was running on before was also 91 Octane Chevron, but this was from a different Chevron station I've never been to other than that one time. I always use the ones in my area, which never gave me problems. I'm not too sure, but I'll keep my fingers crossed and hope the CEL doesn't come on again. And does anyone know if I can still take my car to a place with a reader to see what was throwing the now-gone CEL? I'm not too fond of any of the mechanical stuff under the car, so if this comes on again, I'll just take it to the dealer.

[dc5-K20A3]

hehe..i think you just didn't tighten your gas cap enough previously.

[Hatchtastic]

Honda says we need a service every 5000 miles. In my car I get the check engine light 1000 miles before service time. you being at 9300 makes me think its time for your 10000 mile service;) My engine light went on and off until i took it in. Nothing wrong with my car just needed to pay 200 bucks for an oil change and to turn off the check engine light. I doubt many people take it to honda for service
but that seems to be the time my light comes on