CEL with catback
 

Hi I recently installed an AWE Tuning track edition catback with AWE link pipes that replace the secondary cats I’ve put about 500 miles on the system.

I got a CEL hooked up an OBD2 reader the code is P0420 catalyst system efficiency below threshold bank 1. Did some research and most say O2 sensor looking at the info from the reader both banks 1 and 2 #1 O2 sensors have no voltage while both banks #2 sensors have voltage.

Was wondering if others have experienced this with the O2 sensors not having voltage after installing a new exhaust system any info would be greatly appreciated Thank You

Sounds like the sensors did not get reconnected after installation. The connectors are in a tough spot from the factory, to be fair to your installer.

I did the install myself didn’t discount those sensors so I don’t understand why they wouldn’t have any voltage

If the sensors are connected, look for damage to the wiring and connectors. The sensor itself might also have been damaged.

Very possible that you could have pulled a wire loose in the O2 harness. Resistance test those bad boys. Or just bite the bullet and buy new sensors. ALSO I thee codes when I did my MBRP. Checks for leaks mainly that weird carbon ring on the driver side and the o-ring gasket on the passenger.

Replaced both 02 sensors codes cleared was running good put around 500 or so miles on the car sense replacing the sensors now got a CEL again same thing no voltage on sensors 1 both banks any info on why this is happened would be greatly appreciated

It's a very very small leak. I have I it. Comes on and I just reset it. I've no measure any voltage. Dealer says they'll Dix it. Put that little wire gasket on again. I used this but did a poor job. Many use successfully.

Drivers side where pipe slips on behind primary cat.

My guess from experience is an exhaust leak on the driver side where it connects to the first cat. My Stainless works did the same thing.
I fought with it for a few months and gave up and installed Headers and high flow cats. No problems now.

Had this same issue with my 2nd cat delete catback. Tried resealing it a few times, but it kept coming back. After some research it appears that others with this issue actually had a bad cat. Took it to the dealer and they replaced my drivers side cat under warranty and problem was resolved.

Thanks for the help on this issue looking at doing headers so will need a tune thanks again

Mine did the same thing, when I installed my Stainless Works Cat Back. I got it tuned and no more issues.

If the system, you installed, eliminates the secondary cats, then yes you will need a tune.

You will only need a tune if you have an automatic SS because it will delete the AFM valves by the rear axle.

I have a manual, installed the AWE catback w/o secondary cat delete. Same as OP. No CEL nor tune needed.

Secondary cats aren't monitored. OP most likely have a small leak right at the Catback and/or has an Automatic transmission

I have the M6 so didn’t think a tune was necessary doing a cat back I’ve seen lots of videos and read lots of posts with people removing the secondary cats with no issues went through and torqued everything can’t find any leaks like asrautox said maybe a bad primary cat

Had same code with AWE Catback. Need to put muffler paste on the joint connecting the PLP and Primary Cat Outlet. Once I did that, cleared the code, no more issue