Sensors going off because of non oem catalytic converter?

Better to say what the codes are than just to give paraphrases. I assume the one being paraphrased as "needs OEM converter" is P0420, no?

P0420 would not be causing your ((!)) and VSC lights to come on, and probably not the triangle. Those are likely telling you about something new from 3 days ago, not the year-old news about the converter.

If the OBD tool you are using won't show you the codes behind the ((!)) and VSC lights, you can get those this way:

Blink (a/k/a Flash) Codes – How to. | PriusChat

Regrettably, though, that doesn't work for why the triangle light is on. (And there's a very good chance that you will have only code 58 on the ((!)) light and 51 on the VSC light, which only mean "go find out why your triangle light is on".)

And only a scan tool capable of reading those codes will tell you.

Besides Toyota Techstream, there are some third-party options reviewed here:

Gen2 OBD2 app review | PriusChat

 

If a Toyota Dealership did this job then I'd put pressure on them for installing a CAT that's not compatible and demand they resolve the problem at no cost to you. If they disagree you can go over their heads and call corporate customer service.

 

As I suspected.

That still leaves finding out why the brake/VSC lights are on, and why the triangle is on.

You can quickly find out why for the brake/VSC, from the blink codes. But they might only blink 58 and 51, which would leave only to find the reason for the triangle light.

 

Yup P420.

A good non compliant cat should work perfectly on a G2. I had one installed for almost a year on mine and sold my cat on ebay $$.
Sold my car a year a year later with this $129 cat and NO codes.

Not sure why you used a Dealer to install it as its a very easy very straight forward cat install and a dealer will really bend you over at what $200+ an hour now labor?

I brought my after market cat to a local muffler shop and they removed my OEM cat & installed my new after market cat for $80 and I duked the guy $20. Car actually ran better with this cheapo cat. BUT.. I did it to sell may Cat on eBay it was not stolen. 3 people I knew with a G2 had there cat ripped so I preemptively sold my cat.

Now...having said that your O2 sensor or its wiring may be damaged and the dealer did not address that. The cat and its install may be fine but they just may have not noticed any damage to the O2 sensor wiring or using an after market O2 sensor. I assume your OEM cat got stolen and the awful shenanigans that go with it.

 

link to the aftermarket CAT?

Posted via the PriusChat mobile app.

 

Here is one known to work.

In our case the body shop that installed it initially misswired the replacement Bosch O2 sensor. Not your code but after the wiring was straightened out no codes at all.

Some discussion about this cat including success stories at one shop.

Napa 16337 Catalytic Converter? Check Engine Free? | PriusChat

 

No in your case the code is unlikely to be wiring. In our case it was wiring after a stolen cat was replaced with the 16337 which worked from an efficiency standpoint.