About a week or 2 ago my SES light came on with the P0420 code (Catalyst System Efficiency Below Threshold (Bank 1)). This was a day after I had taken my car in to get TPMS sensors programmed and they also flashed the ECU for an AWC recall.

Anyways, after using Cataclean and resetting the code, it still has not helped, and I've lost several MPGs. Yesterday, there was a faint "rotten egg" smell after I drove home, which apparently is indicative of the cat taking its last breaths.

My question is why did it happen? I've got the Perrin downpipe with high flow cat, and its barely 2 years old. The cat shouldn't die this soon. Haven't done any performance mods since getting tuned at Ivey. Spark plugs were changed around 15k or so (car at 34k miles now). I fear that just replacing the cat will be a band-aid fix, and may not address the root cause of the problem.

Any suggestions? Also, I will have to replace the downpipe/cat. Any suggestions as to what I should get?

Any help would be greatly appreciated,

thanks

 

Hmmm, this might be a long shot, but perhaps they flashed over your tune? Most tuners disable P0420

 

Thanks for the suggestion, but I would really like to resolve it rather than masking it. I'd like to take care of the lowered MPGs and higher emission levels.

What would typically cause a cat failure on a fairly low mileage car?

 

I think what he was getting at was the possibility of the flash putting you on a stock tune, and the appearance of the code being a symptom of that.

 

my bad, when I got the notification, it came through as "Just get them to disable P0420". may have been an edit or something.

I thought of that too, however they insisted that the AWC was on a standalone and wouldnt affect my tune. Annoying to say the least.

Dropping several hundred for a new dp+hfc doesnt sound fun to me right now.

 

Highflow cats don't last as long as oem catalytic converters

 

replace it sooner than later, especially if it is one of those spiral designs over the honeycomb matrix. I had one of these spiral designs break loose and it ended up about 6 inches down the catback and may have contributed to the failure of my engine.

 

^^ Always hate hearing horror stories like that. I checked the Perrin one and its >$500. Any cheaper options you guys would recommend?

 

why not just get a test pipe?

 

I would say if this happened after dealer work, then yes they reflashed your ecu. Have you had any misfires? That could tear up a cat too. Noticable drop in power? Running rich? do you have cable to read out the ecu? Maybe you can send your current rom to your tuner for hime to check out?
Also, instead of getting a new dp, you could just have a new cat welded in place of the old one, or if you dont care about emissions, have straight pipe welded in its place. Just a thought.

Good luck man. Hopefully theres a simple solution here.

 

the P0420 code for inefficiency catalytic converter just mean ur cat is not reading the right amount of oxygen that is stored in the substrate in the cat. Aftermarket HFC doesnt have much precious metal in them, they may not even have Cerium in them which stores oxygen, which that rear o2 sensor is looking for.

If you dont want that po420 code to come on then either put on the stock cat or get a 02 sensor simulator or reflash ur ecu to bypass it, like what others have mentioned.

 

The car seems to run fine from what I can tell. I don't have a cable to confirm my AFR however.

Also its my DD, so unfortunately sending my ROM to a tuner might be out of the question.

Since my downpipe and HFC are one piece, I would have to change both. GRR, and being environmentally conscious (as much as I can be), as well as the smell and added sound of a test pipe, I think I'm going to stick with the HFC.

Thanks for all of the suggesetions

 

You can put on an 02 bung extender on the rear so you don't get the code. I would check under the car and look at the cat to see if there are any dents on it. If a rock hit it, it can crack the materials inside the cat. If that is the case, you can take off the cat and knock off all the material inside and use it as a test pipe.

N

P.S. if the cat did breakup inside..it can make the car lose power from the flow being clogged.

 

I think i'm going to cancel my tmps programing this Friday lol I was just happy when he said $51 to do it.

 

Any number of issues can cause a cat failure. Too rich of a mixture. Too much heat. If raw fuel gets on the cat, it ain't going to last long. With our cats, we have had (off the top of my head) 4 failures in 5 years and 3 of those were in racing conditions (20 minute sessions, tons of heat, etc). I took the original prototype (pre-production unit) off my own car, and the cat core looked brand new after 4 years.

Don't know how much power you're running, but around 500whp is when I recommend running two cats in parallel (Supra guys do this with our units).