Monitors not completing 2001 v6

Okay so I can’t get the catalyst and (I think) Evap monitors to complete. For inspection I can have one not complete but not two. No CEL. See the pics for what the scanner says. Catalyst system efficiency below threshold bank 1. I’ve researched and am curious what the most likely issue is for the catalyst. I went ahead and ordered a new charcoal canister.

 

Your exhaust catalyst (catalytic converter). No idea why you ordered a charcoal canister.

https://www.tacomaworld.com/threads/addressing-some-common-misnomers-of-the-p0420-code.396763/

 

Update. So CEL just came on 62 miles after reset and now I’m up to 6 monitors ok and down to 1 incomplete. Progress???

 

I think what your scanner is saying, is even though you don't have a check engine light on, (MIL = OFF) that you have a pending P0420. The monitors will not complete with a pending code. You should replace your O2 sensors (with Denso parts purchased from a reputable source), clear the pending code, and try to retest the monitors. There are specific requirements to take to clear the monitors. If the codes come back, you need to check for exhaust leaks, and or replace the cats, and try again.

Edit, also don't know why you sent it hard on the canister.

 

Good question on the canister folks.
when I first purchase the truck, a couple months ago, it had a p0441. I changed out gas cap, iffy hoses and dirty air filter and that code went away. Plus PO put some Jb weld on the charcoal canister so that seemed suspicious And some threads say a canister can cause p0441. Plus it’s returnable and cheaper than another $200 ticket for no registration Driving around w no plates is stressful.

 

Thanks for that. The upstream o2 looks new via PO. Can’t tell if it’s denso or not. Downstream o2 looks original so I ordered a sensor to replace. Cats ‘look’ fine. No crushing it dents. Upstream looks like it’s relatively new and it says made in the USA
the truck runs great…. I would think if it was having some of these issues it’d run rough, smell bad and or have bad mileage.

 

That's the thing with this stuff- you can have the smallest thing throwing off the ecu. It's going to notice way before there is a bigger issue.

If the one of the cats have been replaced, I'd be really meticulous in checking for exhaust leaks.

 

I had this issue years ago. Replaced both sensors, didn't fix it. Only new cat did.

 

You'll wanna look at H02S volt data. Upstream H02S volts should "look busy" constantly monitoring fuel ratio and the PCM making it's adjustments. If the upstreams are looking good than the downsteam H02S should be relatively straight line with small movements. If this is the case the Cats are doing their job. If the downstream volt data is still fluctuating and busy looking, than the cats are not doing their job.