GreenMM

Finally got an OBD II scan tool on my car today.
CEL been trippin' over a P0420 code.
It was intermittent the past, say 8 months. 208K mileage. Recently it stopped coming on for about a month of driving and then just came back as soon as I could get my car inspected early (while it was still off). Since my month to inspect the car (Nov), naturally it's been on consistently all month.

I re-set the code today but have not driven the car yet.

Could be an O2 sensor or wiring or short or ground issue to the heated O2 sensor, but likely a failed catalytic converter huh?
Bad gas used, lower octane (once in awhile guilty as charged er, 87 octane), sensors or cat needs cleaning or substrate blocking cat and could be removed? But most likely or certainly a failed cat?

Are there any other Honda or Acura models that a cat could fit from? Planning to hit up the local junk yards and no one has a early model year TSX.

Thoughts?

GreenMM

No smell at all, no sulfur. Mileage is ok, not fantastic. Probably around 28 mpg lately. But that's been about the same since I've owned this car for past two years. Could be a tad less efficient numbers than before.

GreenMM

18160-RCA-A00 this is the OEM 2004 Acura TL, Honda Accord V6, and 03' - '04 Acura MDX sells around $240 ish
18160-RBB-G00 this is the OEM 2004 TSX sells around $650 ish
Just wondering.

Or maybe an aftermarker high flo cat?

TexasHonda

If there are no exhaust leaks, check voltage output (scan tool) of rear O2 sensor for voltage pattern on fully warmed engine. An oscillating voltage from low (0.1-0.2) to high (0.9-0.7) confirms a non-performing converter.

I tried an aftermarket converter (Eastern not cheap) on a Subaru Forester several yrs ago, and it only lasted 1 yr before P0420 returned. My 06 TSX (now my daughter's) has run 10 yrs on original. If I had to replace I would go w/ OEM.

I don't thing converters are available as junkyard parts (federal law on emissions components is what I was told).

good luck

GreenMM

Thanks. Does that mean they are removed prior to being junked in the yard??
Seems odd.
I will try to check the voltage of that. I think my DVM is at another location several hours away.
I'm hoping I can drive the car about 30 miles back to my hometown and not re-throw the CEL and at least get it inspected and then deal with it.

I am also looking into this which I found online here:

"In reference to the anti-fouler here is some info you might need. It is a spark plug anti-fouler. You can find one at Autozone, part #42009 I believe it is made by Motormite. There will be 2 in the package. Take one of them and drill out the hole with a 1/2" drill bit. Then thread that anti-fouler inside the other anti-fouler. Then put your 02 sensor in the bored out fouler and thread into the cat or test pipe. The secondary 02 sensor is just there to see if the cat is doing its job. It will not affect A/F ratios. Now by pushing the 02 sensor further away from the exhaust stream and the fact that exhaust is only passing through that small hole will probably not cause to have a CEL."

link for part @ Autozone:
Spark Plug Non-Fouler for Cars, Trucks & SUVs

TexasHonda

Yes, used converters are salvaged for recovery of precious metals.

Anti-/fouler on rear O2 sensor will work sometimes. If you have an emissions inspection, you may have problems.

To measure rear O2 sensor voltages w/ a DVOM, you will need to back probe the electrical connector. I use sewing T-pins. You will get a confusing stream of digital voltages but watching long enough you will be able to observe max/min voltages.

Surprisingly., the catalytic converter for 04-06 models cost more than later models. Not sure why but it is bigger.

good luck

GreenMM

Thanks for metering tips.
I think I will cross fingers to see if the light will stay off driving to inspection, and then get my DVM next week for testing.

I think our state emissions check is turn key and see if CEL is on. About it. The more anal places will plug into the OBD-II port. There is no tail pipe emissions test here though.

Anyone have aftermarket recommendations? 1st goal is to get CEL off and stay off.
Performance gain or better exhaust note is a nice bonus.

ATLS_666

Coincidental that these codes seem to come on in the cold?

I got was getting a lean code last winter. I swapped out my pre cats and started using Shell 91 with no ethanol and I haven't gotten the code since...knock on wood.

netsx04

What did you end doing about the CEL and the bad catalytic converter? My car has 195k and I've been getting the dreaded 0420 code. Note, I had to replace the A/F sensor at ~170k. I found a used car from '04 TSX with 140k on it for $100. I'm hoping to get another car in the next 6 months so I don't need the cat to last forever. Any recommendations?
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GreenMM

Hi, sorry I saw this so late!
I haven't done anything with the car actually. I re-set the CEL and it was off for at least 200 or more miles, then came back.

It may possibly be related in my case to a failing ignition coil on the #3 cylinder. Not sure, but I'm in modest hopes so.

GreenMM

Btw... if you're in Boston too... we could always think of sharing up a parts car perhaps? I'm not far north from there.