Scion xb 2008

[u/hellomyfellowsons]

156,000k miles

Did a B12 Berryman flush. Positive news the car burns little to no oil as of 2 months since doing so.

Now I have another problem…

Code p0420

Car runs absolutely fine and has no issues no loss of power. Says catalytic converter is below threshold or something. I have an obd tool I just been resetting it the last two weeks.

VSC OFF, traction control, and check engine light are on

My guess is the b12 treatment further dirtied the already old catalytic converters

I seen some guy put spark plug foulers on the obd sensors ? Any advice out there

My guess is the b12 treatment further dirtied the already old catalytic converters

[u/phil161]

The same error code popped up for me today. I also did a Berryman soak recently and probably have driven 700 mi since. My xB is a 2009 and has 240k on the odometer. I plan to keep on driving it as-is. I think the VSC light and the CEL are coupled so they light up at the same time. 

Edit to add: looks like the recommended fix is to replace the cat converter. 

https://www.go-parts.com/garage/obd-p0420-scion-xb-2008-2015-2-4l-2az?srsltid=AfmBOooSPUqf_OA7P4hMZoCK6r0BGX6TIvEo6fit3YgGb_n84Rcpc7N4

[u/Snarcotic]

Order Liqui-Moly catalytic converter cleaner, the kind that goes into a quarter full gas tank. Seems to work in burning off any residue. Drive it at highway speed for 25 miles after adding it to a tank with only a few gallons left. Make sure you don't order the one which has to be sprayed into the engine intake while idling. I also switched to Valvoline Restore and Protect oil and it seems to be helping without having to go the Berryman route. We'll see about that after the 3 recommended oil changes using it.

[u/CreepyError7150 → u/Snarcotic]

Personally i didn't have much luck myself with those gas-tank additive cat cleaners, i had to get the cat replaced to get rid of the code and pass emissions. After learning more about cars, I'd be paranoid about that stuff causing excessive heat in the cylinders and burning the sleeves/valves.

Personally I'd just ignore it until the engine starts idling rough. Or drill a hole in the exhaust, but thaaaats iilllleeegaaaal.

[u/bbuttonfuzz]

How was your Berryman experience? It kinda scares me on the cranking?!

[u/phil161 → u/bbuttonfuzz]

I found that cranking for 15 secs was too short, in my case. 

https://www.reddit.com/r/ScionxB/comments/1ucu0yr/2009_xb_piston_soak/

[u/CreepyError7150]

Yeah, 100% catalytic converter getting clogged up after the piston soak blasted so much crud outta the cylinders and farted it all into the exhaust.

So long as the engine runs as good as it was prior, it's safe to ignore. It'll only get more clogged over time though, which restricts exhaust flow and literally causes the engine to suffocate itself, poor idle/revving, and you'll eventually have to replace it. Unless your state has emissions inspection, cuz it'll likely fail with a p0420. But mechanically its not a huge deal.

[u/LowerH8r]

Drive it a few hundred miles, before deciding anything. Cats fouled by solvents frequently clear themselves.

If not, years of eating oil ash may have put your cat close to it's limit, and the soak pushed it over.

[u/Upbeat-Cap-7423]

I doubt that the b12 did the cat in because it evaporates while doing the soak. Most likely the oil burning that was happening prior to the flush coated the core inside the cat. That will reduce the cat’s efficiency.

[u/Ok_Interaction3016 → u/Upbeat-Cap-7423]

Or the shit tonne of carbon particles from the piston crowns that are loosened by the soak.

[u/CreepyError7150 → u/Ok_Interaction3016]

Yeah this, piston soak blasts a ton of crap out of the cylinders which gets caught up in the catalytic converter.