error codes P3190 and P0420

I would first of start by replacing the oxygen sensor. See if that takes care of the problem with that. Second when you look at the exhaust you will see a valve on the exhaust, see of that moves freely. If it's tight, squeaky, lubricate it with anti seize. If the cat is bad, you can get aftermarket replacements easily that are way cheaper. The speed sensor ill look into.

 

Hello,

As I was reading your post, I got the impression:

• not technical
• frugal

Would you consider changing your profile or let us know what area of the country you live in? That way the independent mechanics who hang here and those we know of can be shared.

Toyota service centers have some pretty strict requirements that includes standing by their work. New parts they can warrant but used parts . . . no way. In contrast, an independent mechanic is more flexible about parts but as a general rule, they will go for a known source, a rebuilder or known 3d party supplier. Scrap yards are more the home of owners, shade-tree, and folks like me. <grins>

You've got the right idea, two separate issues:

• catalytic converter, oxygen sensor - the oxygen sensors have two functions, mixture control and monitoring the catalytic converter. The sensors detect the boundary between a rich and lean mixture so the engine controller can adjust the fuel injectors to provide optimum mixture, stoichiometric. There are two oxygen sensors with the catalytic converter between the two. The ratio of the oxygen signals lets us know if the catalytic converter is 'burning off' the hydrocarbons from a rich mixture or 'reducing' the nitrogen oxides from a lean mixture. If an oxygen sensor fails, the mixture control would not work and fuel efficiency would be bad and there would be an indication that the catalytic converter has failed.
• wheel speed sensor - this is how traction control works so if a wheel starts to spin, the car 'adjusts' so it remains steerable and brakes straight. It is a safety feature.

The oxygen sensors are in a terrible place, the very hot exhaust. So one reasonable approach is to start with just the oxygen sensors. This should restore mileage and finally provide a true metric of the catalytic converter. However, there is a risk that the catalytic converter has been 'poisoned' by a too rich or lean mixture. But there are 3d party, catalytic converters and approaches IF you have a cooperative mechanic.

Please read the sticky about 'who should own an NHW11' and lets start with:

1. self-assessment - your skills, interests, and availability of a cooperative mechanic to help on some of the harder to repair parts.
2. a plan
   1. wheel encoder - could be a loose connector but really is for stopping in wet, snow, slippery, or emergency situations . . . I would defer until we know you will keep the car BUT do it once a decision to keep it is made.
   2. oxygen sensors - there are two and some have swapped front and back but this is a poor practice as it may simply swap the position of two, failed sensors. Buy replacement oxygen sensors and for $500 (or less) find out.
   3. catalytic converter - if you live in a state with annual inspections, there is no choice. But I know of at least one Alabama (not mine) NHW11 with a totally inert catalytic converter and it runs fine ... the oxygen sensors are the key part.
3. you and/or a mechanic - turning a wrench is not that hard but having the confidence to do it is. The oxygen sensors could be handled by any independent mechanic or take it to the Toyota shop. Tell them you don't have enough to do all changes at once so you'll bring it in as you can afford it. But there may be local, evening courses that teach people how to do light-duty car repairs. It can be terribly empowering to go from always having to 'ask' versus having your own tools (not many are needed) and doing it yourself.

GOOD LUCK!
Bob Wilson

ps. We're all volunteers here and our 'pay' is feedback that we've helped someone. So even if you decide on another approach, please post a 'good bye' note and summary. <GRINS>

 

Wow! I'm a pre-Facebook artifact so I'm not in the habit of clicking Like buttons on things, but Bob, that was a fantastic model of an informed, informative, attentive, helpful post. Even if we were never to hear back from the OP, I'd still have been reminded why I keep coming around.

Thanks!
-Chap

 

Avi's Advanced Automotive frequently posts here with impressive technical content and details:

7776 Foothill Blvd Unit 4​

Tujunga, CA 91042​

818-352-0997​

Their web page says they are "Open 6 Days" which is a sign of customer respect. I have never met them but I would follow their lead.

BTW, if you'll check, there are two oxygen sensors and I'm seeing the parts running between $50-$150 (the cheapest ones require some soldering to reuse the old connectors ... labor). I would let Ari provide the parts as they know who are good and not-so good suppliers and not blink an eye if they suggested replacing both rather than one. They will also get a first idea of the health and status of the exhaust system.

I know time is precious but would suggest taking a peek at the Environmental forum. I met Doug Schaffer (tochatihu) at a tour of the Toyota Camry factory in Georgetown KY who is an environmental scientist currently in China doing field work and training. But in spite of being on the other side of "the Great Firewall," Doug still frequently posts informed and insightful news about current environmental research. In the seven years or so I've known him, he has always been even handed and fair in spite of the 'spiteful' who like to pester us. <grins>

GOOD LUCK!
Bob Wilson

 

+1 on Avi's Advanced Automotive. He is always willing to help and is very knowledgable. Even if you have to drive a ways to get to him I would think it to be worth it in your case.

 

And hopefully you don't need a new CAT in CA.

I don't think there are any legal aftermarket CATs for CA and the OEM is $$$$$$$.
It's also against the law for shops to sell used CATs.