P0420 CEL 2017 Toyota Tacoma TRD Sport DCLB 3.5L V6 AT

Update** Installed new exhaust manifold/CAT and cleared CEL and CEL has not come back.

Sprayed PB blaster a few days in a row before install and had no issues at all.


2017 Toyota Tacoma TRD Sport DCLB 3.5L V6 AT

I did quite a bit of research, There wasn’t anything I could find on the internet about my year and model taco. Only 1st and 2nd Gen tacos with over 400,000kms that had a P0420.

P0420 comes up as emissions system. Which could be a few things, O2 sensors, catalytic converters, and or exhaust manifold.

Im pretty disappointed considering my truck only has 120,000kms on it and Catalytic converters are supposed “to last the life of the vehicle”. My best guess was a dud O2 sensor which caused my engine to run rich and clog up my CAT.

I tried duralube catalytic converter cleaner which others had some success with. You pour it into a full tank of gas and go for a drive and get your engine nice and hot. I had no luck as the CEL stayed on.

I don’t have a fancy scanner but it told me two codes P0420 for bank 1 (passenger side), so I started off with replacing the O2 sensors Denso brand. Air-fuel Ratio sensor in the front and regular O2 in the rear.

I cleared the code, but it still came back. I didn’t want to bring it in to the stealership as they charge a fortune and I haven’t had the best of luck dealing with them.

I ended up taking it in to get a diagnosis after putting it off for a couple months. They said my bank 1 CAT converter had 0% reserve capacity, and that I needed a new Catalytic converter and new exhaust manifold gasket. They quoted me $2564CAD to fix it!!!

I’m balling on a budget so I went on rock auto and found an OE replacement Exhaust Manifold/CAT converter (all one piece) for $496CAD which comes with the necessary hardware (nuts, bolts and gaskets) and bolts up to the existing exhaust.

The CAT should arrive next week. The biggest complaint I have read that people have with working on the exhaust manifold is snapping studs, I’m crossing my fingers and hoping that I’ll get away with reusing the same studs and that I won’t have to drill them out of the engine.

 

More than likely a gasket leak. A catalytic converter failure so soon out of the blue is not likely

 

We've seen gasket leaks cause p0420 on 3rd gens, its definitely worth a shot. Don't throw sensors at it.

 

If you are worried about snapping studs, Iwould start soaking them now with PB Blaster or something similar.

 

It would cost less to pay an actual tech to properly diagnose, rather than throwing parts at it.

 

Have you looked into the Emissions warranty in Canada? In the US it is 8 years or 80,000 miles.