CEL on then off
 

I was coming back from home after thanksgiving break when about 30 minutes left in the trip the CEL came on. Due to this being the last week before finals, I've had 2 projects, a paper and a quiz to study for so my first available chance to go to see what the CEL is would have been this weekend.

The thing is, when I got in my car to head to class today the CEL was gone. Now I'm rather sure CEL codes are stored in the PCM even when they go away, but I wasnt sure if the CEL was supposed to go off unless something was done about it. So should I still have it checked? While it was on I couldnt notice anything specifically wrong aside from the light being on so I honestly have no clue what it was (did check gas cap and oil level). Thanks for help and sorry if this is a repost... didnt find anything about CEL just going off after a couple days...

If Autozone nearby, then go have the code read for free. At least you will know what was stored. I'll bet a misfire, but go see what it says.

I recommend getting this http://www.scangauge.com/
Then you'll be able to read your codes etc.

Misfires are fairly common and happen every so often.. But if they become more numerous time to check stuff.

it happens all the time man, no sweat, unless u get 5 in a row, then its time to check ur coils and plugs

Are coils and plugs the source of all RX-8 problems? ;)

The first step when chasing down the cause of a CEL is to read the code.

Ken

would it stay on for misfire? it was on every time I drove and stayed on from sunday night when it came on until thursday morning when it just didnt come on at all. If it was misfire I thought it would have gone off? might be wrong though. If I have time I'll try stopping by an autozone to check the code or something

Did the day's temperature drop significantly? CEL can also be caused by the seal around your gas cap warping because of high/low temperature. Happened to me last winter and again a couple days ago. When the area warmed up yesterday, CEL disappeared.

I was actually wondering if temperature mattered cause today was a very little bit warmer... maybe 10 degrees max... and drove tonight when it was a little lower again but remained off... next time it drops a decent amount I'll keep an eye out.

about to head off to work... but will any other places like advanced auto parts pull the codes? The closest autozone is like 20-30 minutes I think but there's a series of other stores within 10 minutes... probably gonna check after work but figured I'd see if anyone knows before I drive out there.

cat or no?

"P0420 Catalyst system efficiency below threshold ON 2 Catalyst"

I have the RP supercat... if I remember right there have been a few people having their supercat fail prematurely so could it be that?

yes.

beers :beer:

lol... is it likely that? and has there been any reason given as to why that would happen? I know some people in the past have had them replaced for free but I dont seem to recall there being any changes in the catalyst

sorry for spam but bump!
been busy last couple of days so havnt had the chance to ask...

is this something I can assume is the case? Since others have had their faulty supercats replaced in the past for free, I assume I'd be able to get the same deal, but should I have it physically checked before pursuing a replacement? I dont exactly have the means to check it myself and I dont want to waste the time replacing it if it is still in good condition and such... so any replies are appreciated once again

I had a supercat that was fine and it gave me the CEL on a regular basis. You can unbolt the cat and look at the comb and see if it seems broken down or 'burned'.

In the end it was enough to make me decide to just go to a full straight pipe.

+1

Hmm... this is the first issue and it's been around 10k miles but not sure if that really means anything. I did consider the straight but wouldnt that have a constant CEL? I've seen threads asking about if you can fake the sensor for it to prevent CEL but dont ever remember seeing a definitive answer. guessing since your hadnt actually failed you didnt get one for free or anything..

mines come on a few times for a misfire, itll stay on for a day then when you fire it up the next morning its off.

Bump.

Same thing happend to me last week. but it stayed on for 2 days then went off.

happend 7 months prior to that too. same thing, it was a misfire in cy#2.

guess it's time to change plugs and check the coils!

well, back for an update. I havnt changed anything so far since it could have been an erroneous code. I did, however, notice today that my mileage is quite terrible. I'm going to actually pay a bit more attention to my driving style over the next couple of days and try to drive a bit more efficient to see if it was just how I was driving recently. If my mileage is correct, I'm getting about 10 mpg which seems quite low. I know for a fact there were a few times I drove spiritedly but still seems low even for that. I'm going to finish off the tank and see how that goes for now.

bump! just wanting to see if someone could confirm if the CEL code I got could be related to the low mileage I've been getting.

yes a failed cat could cause bad gas mileage.

beers :beer:

well, went to the dealer finally and got coils and plugs replaced under warranty and was told I need a new cat but cant be replaced udner warranty since I have aftermarket. Going to email RP tonight to see if I can get it replaced since it failed in under 15k.

continuously reviving this thread it seems :sweatdrop but I just remembered something else from my trip to the dealer yesterday. A couple things actually, but the first is a lot less interesting. First thing was the tech who worked on my car came in and had a bottle of synthetic oil I had in my trunk and said that I shouldnt use that because it will void the warranty and then asked if I had used it (giving me a look like "say no and you're free") so I just said no and he said good and went back to work.

The next thing interested me though. When I was leaving to go to my car after they had finished the plugs, coils and my tail light, the tech told me that the coils will go bad again (matter of time kinda thing) and said something along the lines of "and when that happens we'll see if we cant get a new engine in your car for you. But that's just between you and me". Just struck me as kinda odd. Not sure if I should feel good that a dealership is willing to hook me up or if I should be worried lol. Either way, all is good for now. Going to be getting my supercat switched out for a new one so that worked out well.