Catalytic converters for a Gx470 (1 Viewer)

[Bamagirl]

I've been having issues with my GX for the past couple of weeks. Two weekends ago I replaced the alternator and now I'm getting codes for bad catalytic converters. The right is completely stopped up and the left is almost stopped up. This was verified at a shop that ran diagnostic testing on it and measured the exhaust output.

Had anyone ever replaced these? Is there a good aftermarket OEM part I can use to replace them?
Lexus part is $635.42 a piece. Called Toyota dealership and it uses same part as Lexus but wouldn't sell it for the Lexus or something like that. This may of been a break down of communication between my dad and I over the phone. He's the one who talked to them.

 

[GXO]

The cats are attached to the exhaust manifold. They are not cheap to buy or to install. Good luck

 

[Hoosier Daddy]

My father-in-law just replaced one of the cats on his 2003 Sequoia. OEM cost was $950 for the part at discount sites online, so we decided to go aftermarket.

Here's what I learned from my research:

Look up the federal law on catalytic converter replacement. His old one had rusted off and his truck was old enough that we could replace the cat with aftermarket.

There are different grades of replacement cats, and you should determine if your truck has California emissions or 50 state emissions. There should be a sticker under the hood. The two versions of cats are not interchangeable.

The two brands of aftermarket cats with the best online reputation are Magnaflow and Eastern. I could find a huge amount of positive reviews for Eastern with a few negative reviews. Magnaflow had fewer positive reviews in my research but also had a smaller proportion of negative reviews.

We decided to go with Magnaflow, found on Amazon for $250. The Eastern cat was $150. Fit and finish of the Magnaflow was impeccable.

You can sell your old cat to a salvage yard or metal recycler. If there are none local to you, there are places online that buy cats.

Looks like Dan is right about the manifolds. Good grief, that could complicate things. On the Sequoia the cats had their own section of exhaust pipe.

 

[Bamagirl]

Yeah the estimate to replace is very painful. It's been a rough month where the GX is concerned. I'm researching and asking questions and trying to get as much info as I can, hence why I posted here. I figured I could reach way more folks here with some experience and knowledge.
The GX has one more chance or it's going to the glue factory.

 

[kbahus]

Are there any driveability concerns or does it run and drive normally? Would you know if there was an issue if the check engine light was not illuminated?

 

[Bamagirl]

When I noticed the lights on it didn't seem to change the way it drove but I didn't take any chances. I drove about 5 miles to my dads farm and parked it.
The weekend before it went totally limp and then finally died on the side of the interstate. I replaced the alternator. It's been driven less than 25 miles since all that. I was going to make the 100 mile drive home when the lights came on so I left it and have been researching and talking to mechanics since then.

 

[HomersCanyonero]

What's the CEL code that you are getting? I remember getting several lights on the dashboard including CEL, but I just replaced both O2 sensors and everything is good. It's been like 5K miles since I did this and no more CEL or other lights on the dashboard. I forget which CEL I got.

Also, there are some shops here in California that will try cleaning the cats. It doesn't always work, but sometimes it does and it only costs like $30 or so to clean them.

Finally, what are the laws in Alabama with regards to cats? I googled it and got mixed results with some people saying there's no smog checks.

 

[Bamagirl]

P0430 is the code.
We don't have smog checks in Alabama.

I thought I'd go to the muffler shop that added my exhaust and see if he has had any experience with this and see if he has any suggestions. Maybe there is an alternative to cut the old one out and weld another in place.
I've been told to clean the MAF and see if that helps. I plan to do those things today. After that I will be on hold until I learn more from others.

 

[GXO]

Typically the P0430 has data behind it (Bank #, Sensor #) and is usually related to either an O2 sensor being bad or a Mass Airflow Sensor being dirty. A clogged cat is not normal. If you get the Bank and Sensor and it shows ALL bad (bank 1 and 2, sensors 1 and 2) you can maybe have a cat issue, but I doubt it. Bank 1 is driver side, Sensor 1 is pre-cat O2 sensor.

 

[GXO]

Also, in terms of cheap alternatives...replacing O2 sensors is simple, and cost about $30-60 a sensor. That and a can of MAF cleaner is a lot cheaper than a whole new manifold + labor to install.

 

[Bamagirl]

The code said bank 2 and I believe that meant right rear. I agree with you about cheaper alternatives.

 

[GXO]

Bank 2 is passenger side. So sensor 1 is front, sensor 2 is back. If it is just one, I would totally do the sensor only as a first step.

 

[Bamagirl]

I took the negative cable off and cleaned the MAF and replaced the air filter. Put everything back together and cranked it and no lights. Drive it 3.5 miles and no lights. I replaced the cabin air filter too since I was doing the filter thing today.
Will drive it more tomorrow and see what happens.

 

[HomersCanyonero]

I had a smog check due when I purchased my 2003 GX470 and the CEL and the dashboard lights went on. I checked the CEL and cleared it. I drove it like 75 miles and no CEL. I took it in for a smog check and the computer was not ready. They shop told me to drive it some more. The CEL came back at 90 miles. I cleared it again and replaced both O2 sensors. I drove it another 90 miles and no problem. I took it in for smog check and it passed without any issues. It's been like 5K miles and no CEL has come back.

So, it takes like 100 miles of driving in streets, freeway, stop and go, etc. to go through the whole cycle. My experience was that changing the two down O2 sensors solved my problem.

I got the two downstream O2 sensor on Amazon. They are under $40 each right now on 9/1/2017
Denso 234-4261 Oxygen Sensor

 

[HomersCanyonero]

I have this diagram in case it helps. There are 4 O2 sensors. Two upstream and two downstream. The downstream ones I replaced are labeled 89465 in the diagram.

 

[GXO]

Get an O2 sensor wrench if you are doing it yourself. SO HELPFUL!!!

I believe they are all 22mm/7/8" bolts. I got one from autozone and it fit. Made it a breeze. Hit it with PB Blaster the night before.

 

[Bamagirl]

Lights came back on after 12 miles. Priced the o2 sensors and had code checked and still reading the same code. Upstream part is higher than down stream.

If I replace o2 sensors and still have issues and have to truly replace the catalytic converter, is the new catalytic converter going to come with o2 sensors? Replacing sensors is my cheapest option. I've been on multiple forums, YouTube, here and also talking to experienced Toyota owners. I'm so frustrated with it.

If I replace o2 sensor, should I replace one first and see if that fixes things? If so which should I try changing first? Upstream or downstream?

 

[HomersCanyonero]

Catalytic converters do NOT come with O2 sensors. You have to buy everything separate, so you wouldn't be wasting money by attacking the O2 sensors that might be bad per the codes that you say it's throwing.

In a previous post you said that the codes were saying it was the right rear. This usually means the downstream one. Pleae confirm that the codes are telling you a specific O2 sensor and just replace that one. In my case, I decided to replace both downstream O2 sensors because I was throwing a code for one of the downstream sensors and they were easier and cheaper to install.

 

[HomersCanyonero]

By the way, the O2 sensors and catalytic converters are common problems with a lot of cars. I'm having issues with my daughter's 2004 Acura MDX and those things are also a PITA and expensive. I had problems with the O2 sensors on my 80. So far, I've been lucky that replacing the O2 sensors has resolved my problem on 3 out of 4 cars/suvs that had this issue except the 2004 Acura MDX which wants a new cat!

Anyways, I know you are frustrated, but just try replacing the O2 sensors and see what it does. If it does need the cats, then I could see that you might want to cut your loses. GX470 is typically very reliable, but there are some common problems. Here's a list that I compiled from various posts....

Some common issues (unconfirmed list) with the GX470s are:

1. Chrome/painted rims corrosion issue in some regions (option to replace with deeper FJ alloy wheels)

2. A/c weak in some hot regions in 2003-04 models TSB

3. Dashboard cracking issues in most years

4. Rear air springs fail (option to replace with OME 2896 rear coils and N60004-S rear shocks)

5. Front e-shocks with coil springs (option to replace with OME 2885 front coils and N90000-S struts or Bilstein 6112 coilovers)

6. Ignition switch pins wear out (replace pins)

7. Transfer case o-ring leak (replace o-ring)

8. 2005+VVTi had air injection pump issues (AIP bypass kit $180 to $250 for part plus labor)

9. Seeping radiators (option to replace w Koyo/Denso rad when doing timing belt and water pump)

10. Rear doors may be difficult to open (listen for unusual noises when opening): redesigned lock assembly needed

11. Front brake calipers seize (flush brake fluid and clean or replace calipers)

12. Driveshaft clunk when braking ($260 OEM replacement part; DIY)

 

[Bamagirl]

Yeah I had to replace the radiator which started me putting money in it.
It got me out west and back and that's what I bought it for. I keep vehicles a long time and had intended to keep this one.
I've gone and bought the o2 sensor and the wrench Dan spoke of. I may need to listen to some spa or zen music before attempting to replace it. As mad as I've been towards the vehicle I need to be as chill as possible before attempting this step. No threat of small children or old church ladies being present while I do this so if I start cussing like a sailor only the dog will be near to hear it. lol