jcather

So last Friday I swapped my stock exhaust for a Corsa extreme. (cat back)

Today the engine light came on.

Could be a coincidence, but could be something else.

So I was thinking that maybe I need the computer reprogrammed since I changed the exhaust.

What have you guys seen ?

Thanks

Dcasole

Coincidence ...... maybe , did u install the afm valves , at any time did u unplug them ? just read the code and see why its on ...

Internets_Ninja

Cactback shouldn't cause a CEL but it can if you have a leak near an O2 sensor or if you tightened the AFM valve modules or NPP valve modules down too tight. They have a resistance area they operate in and if it is too high due to over tightening the small bolts it will throw a CEL. It would be much more helpful to determine the issue if you could get the codes from the ECU.

jcather

thanks guys I will get the codes and post back

jcather

Code was increased flow at cat, had tech clear it and we will see if it returns.
Talked to shop that installed exhaust and they said they have seen this on other cars where they installed a Corsa system
It usually clears once the computer has sync'd up

Will keep you posted if it returns

jcather

Well it came back after a few hours, I guess I will contact corsa

Internets_Ninja

Never heard of increased flow at cat code before. A P0XXX identifier would help.

Also, what exactly did you install? And what exactly did you remove from the car in regards to the exhaust system?

jcather

P420 bank 1

Internets_Ninja

Do you have headers? That is a cat efficiency code.

4XLR8N

jcather

no headers

Dcasole

Look for exhaust leaks especially if they loosen all your pipes to install and line up the cat back

Also check the rear 02 sensor wires to make sure they are clipped on tight and the wires are not pinched

Lastly make sure they did not break the O2 sensor

No Cat back install should throw a CAT efficiency code and then after reset , set the code again something else is wrong , My bet is one of the wires is off or cut

Dave

Dcasole

HMMMMMMM That code has nothing to do with what he told you …In creased Flow at the cat …… omg that's a new one and I am sure he told you that he sees it all the time , its because he is doing something wrong

I might just take it somewhere else as this guy is full of SOUP …..


here is what P420 is and what it means …...has absolutely NOTHING to do with more airflow thru the cat , if anything its less airflow due to a plugged cat or a malfunction with the o2 sensor

https://www.obd-codes.com/p0420



Dave

Internets_Ninja

Do you still have the factory exhaust manifolds and primary catalytic converters in place?
Have you checked the drivers side for exhaust leaks?

jcather

Factory manifolds and cat's are in place.

Internets_Ninja

Then it is likely a leak near the rear O2 on the driver side. It could also be a loose or damaged O2 sensor. But take a look at the driver side rear O2.

jcather

Just to be clear, the rear CAT's were removed when the new x pipe was installed.

And you are referring to where the front CAT connects to the x pipe, correct ?

sTz

I never had an issue after installing the Corsa Cat-backs... Hopefully the cleared cel won’t return.

KemahGT

Rear cats will not cause a problem when removed. Front cats will.

KemahGT

The installer likely screwed something up. A cat back installation will not cause these codes. As a matter of fact, the installer had no reason to touch anything upstream from the rear most O2 sensor. You’re getting good advice in this thread. Check your O2 wiring.

The installer had absolutely no reason to touch any of the four O2 sensors. They are not in the way and all of the exhaust to the rear bumper from the mid pipe forward connector is the only thing that they would need to remove, replace or adjust.

Good luck!