I was driving today, just like cruising and all of a sudden I turn to look at my dash and I see my engine service light is on. When I first started and drove the car this morning there were no problems, but after about twenty minutes of driving the light game on. This never happened while I was stock. My mod's are in my sig and all of which I am tuned for. I let the car idle and that was fine, I put it in fifth and floored it to make sure there were no leaks or anything and the car is boosting around 21 psi and holding so no problems there (its like 85 today in Michigan)....I have no idea what it could be somebody help....please

 

do you have a tbe?
If you do, it might be code p0420. Cat deficiency (hence no cat).
Go to autozone and get the code pulled to find out exactly what the car is saying to you. It's free of charge.

 

I have the Buschur TBE with Bullit Muffler...but the car never had the light on before why would it do it after I got tuned for everything....becasue there was a time where just the TBE was on my car and it drove fine

 

Its its prob your cat...I had the same problem

 

auto zone will tell you everything i got engine code reset the battery

 

sounds like the cat what else could it possibly be?

 

As FAR as I know. And this is most likely not your problem, but just something I am almost positive on. When you're in 5th gear, even without an MBC or EBC, you should be pulling more then 21psi EASY. Since there's so much load on the car. 5th gear you should be like 23 - 25psi if you floor it in low RPMs.

 

Do you have an O2 simulator fix for your TBE?

 

go pull the code!

 

im throwing the same code, replaced the front o2 and it went away for about 2days, then i got on the car a little and the ses came back on again, and i have a high flow cat. this only seemed to happen when i vta with my hks. when i had my forge on recirc it didnt throw a code. so if it keeps happening im gonna throw the forge back on. the code keeps saying below efficiency threshold. whatever this means, but i want to take care of it, so if anyone has any suggestions on this, please post.

 

jason900rr, do you have a mechanical or electric o2 fix for your high flow cat? you need one for the high flow cat.

 

how about the hose going to the egr valve?
It's right under the intake

 

That code is for the rear 02 sensor its saying that the crap coming out you tailpipe is hurting the enviornment. Get an O2 fix.

Original poster:
Its probably the p0420 cat code but the best advice to everyone that gets CEL's is to get the code pulled. I laugh everytime somone posts up saying they threw a cel and ask the board "what can it be". We're not OBD-II scanners

 

Will this help?
http://cgi.ebay.com/ebaymotors/WRX-S...spagenameZWDVW

 

good info,I was just about to seach for the part number but this is much easier.