Catalyst System Efficiency Below Threshold

[Batmanntexas]

Anybody got any ideas on how to go about correcting an "Catalyst System Efficiency Below Threshold, banks 1 and 2 (codes P0420, P0430)? The rear O2's have already been tuned out. The car is a 2012 LS3, LT's, HF Cats, Whipple, LS9 cam, and custom tuned. I run a wide band O2 sensor as well, and the AFR is always good. It also throws these two codes:

P1133 Oxygen Sensor System - Too Few O2S R/L and L/R Switches . (Bank 1 - Sensor 1)
P1153 Oxygen Sensor System - Too Few O2S R/L and L/R Switches. (Bank 2 - Sensor 1)
Do I need new O2 sensors? The car has about 15K miles on it, only about 4K since the upgrades. Thanks for any help/advice.

[Sp00ner]

Is the wideband installed completely separately? I had that issue when initially installing my LC-1 in place of the factory O2 sensor in my Saturn, before I tuned the narrow band output correctly.

[Batmanntexas]

yep, the wide band is in its very own bung, offset from the front O2 sensor.

[litle88]

I bet the cats are trashed. S/c and cats don't mix well together due to the higher exhaust temps. They'll clog up.

[axis]

Originally Posted by litle88

I bet the cats are trashed. S/c and cats don't mix well together due to the higher exhaust temps. They'll clog up.

+1

Put it up on the rack and check the cats. It's very well known that aftermarket HFC's don't hold up to boost. Several threads on it in this section as well as the FI section.

If they're trashed, just run a pipe through them and hollow them out. No sense in buying a set of offroad catless pipes to do the same thing.

[3rdgen3]

The bottom line is, they were not tuned out PROPERLY.

You will need to have a competent tuner look at your tune.

Even with trashed cats (or no cats) you should NOT get an efficiency code below threshold if they are tuned OUT.

HP tuners gives the tuner the option to put the rear o2's in an 'ALWAYS READY' state and to NOT trigger a CEL. This isn't happening in your case.


Get your tune checked..and if you do have real cats on there, get them checked (and punched) as well.

[Batmanntexas]

Originally Posted by 3rdgen3

The bottom line is, they were not tuned out PROPERLY.

You will need to have a competent tuner look at your tune.

Even with trashed cats (or no cats) you should NOT get an efficiency code below threshold if they are tuned OUT.

HP tuners gives the tuner the option to put the rear o2's in an 'ALWAYS READY' state and to NOT trigger a CEL. This isn't happening in your case.


Get your tune checked..and if you do have real cats on there, get them checked (and punched) as well.

The rear O2's are turned off, I have verified it myself, as I have my tune file loaded on my computer. It is calling out the front sensors as opposed to the rears.

[Batmanntexas]

Originally Posted by axis

+1

Put it up on the rack and check the cats. It's very well known that aftermarket HFC's don't hold up to boost. Several threads on it in this section as well as the FI section.

If they're trashed, just run a pipe through them and hollow them out. No sense in buying a set of offroad catless pipes to do the same thing.

Thanks guys. I'll check out the cats when I get back home on Monday and post the results.

[Batmanntexas]

Well, I pulled the cats today, and they are in perfect shape. O2 sensors looked fairly clean as well. I am at a loss here.

[Batmanntexas]

Somebody mentioned that with putting long tube headers on, the O2 sensors are farther down stream now, causing the codes. Thoughts on this hypothesis? I have contacted my tuner, now I'm just playing the waiting game...

[axis]

Originally Posted by Batmanntexas

Somebody mentioned that with putting long tube headers on, the O2 sensors are farther down stream now, causing the codes. Thoughts on this hypothesis? I have contacted my tuner, now I'm just playing the waiting game...

It's the rears that throw the code when you have LT's. Since yours are suppose to be tuned out, THAT shouldn't be it. Sounds like something your tuner should deal with.

[3rdgen3]

Originally Posted by axis

It's the rears that throw the code when you have LT's. Since yours are suppose to be tuned out, THAT shouldn't be it. Sounds like something your tuner should deal with.

Which is exactly what I said earlier.

If it's not a tune issue, then their has to be an exhaust leak.

[Batmanntexas]

Thanks all for the advice! I can definitely say there isn't an exhaust leak, anywhere. Looking through the tune file, those codes were (P0420,P0430, P1133, and P1153) were never disabled. Once I get with my tuner, or somebody else with the HPTuners program, I'll get that remedied. Thanks again to all for their advice and $.02.