CEL Codes 25 & 26 (1 Viewer)

[BTLSHP]

These codes popped up for the first time two days ago. I have read what I can find on the issue and seen the OTRAAM video. I suspect O2 sensor related issues based on my limited diagnostic skills and tools.

In the week ending July 21, I replaced all cooling, vacuum and transmission hoses. Except for a knock sensor wire I broke in the process, it has run fine without codes until two days ago. Then 25 & 26 appeared. Separately, I purchased a Toyobd 1 tool and connected it to an old Android phone.

What I see is as follows:

The Bank 1 O2 Sensor comes online quickly after start-up and on the short term fuel trims you see the expected pattern flipping between rich and lean. I have not timed it at 2,500 RPM yet, but I would expect it to be in excess of 8 cycles per 10 seconds.

The Bank 2 O2 Sensor is different. From a cold start, it flat lines and shows +20 Rich until the coolant reaches about 160 degrees and then begins in the normal pattern of flipping between rich and lean. That is until I let off the gas as in a descent or coasting at which point is shows +20 Rich and stops cycling between rich and lean.

In looking at the O2 Sensors, I have several immediate issues:
- I can't get the plastic connectors apart after soaking in PB Blaster and Silicone, the things seem fused together. So, I can't test the heater circuit per the FSM but I suspect the bank 2 is shot.
- How the hxxx does anyone access the nuts (or what is left of them).
- Which Cat is bank 1 and which Cat is Bank 2?

I am happy to buy two new O2 Sensors. The outboard stud of the outboard sensor is dust, nothing remains there is something on the inboard stud but not much. On the inboard sensor there are remnants of nuts but nothing that a wrench will bite on. I have been soaking them in PB Blaster.

One sensor is original to the car the other was replaced in 2015 per a service receipt. I never loved the people my father used to service the car in that era, but I have no reason to doubt their invoice.

Am I correct in being focused on the O2 sensors at this point? I can't imagine a vacuum leak affecting Bank 2 only and I have no hint of an exhaust leak. the down pipes are relatively new and the manifolds seem fine.

Who do I go to to remove these sensors? Muffler shop?

Thanks in advance for any thoughts and guidance.

 

[BTLSHP]

Ok, Bank 2 is the outboard sensor? with the short lead?

 

[Rifleman]

- How the hxxx does anyone access the nuts (or what is left of them)

Remove the exhaust system
If you end up dropping the exhaust system to get at those nuts here are the part numbers for the exhaust system gaskets to put it back together
90080-43036 for head pipe to exhaust manifold gasket, 90917-06076 cat outlet gasket, You'll need 2 of each gasket

 

[Rifleman]

When you ran your test on your O2 sensors ,does your testing tool give you the voltages that each sensor is running at?
Below is a link to a web site that talks about O2 sensor voltage and what they mean,

Vf1 voltage

Vf voltage information about Oxygen Sensor

alflash.com.ua

 

[BTLSHP]

When you ran your test on your O2 sensors ,does your testing tool give you the voltages that each sensor is running at?

At this point I do not know how to extract the data file so all I have is a visual. I expect I can get voltages by running the test with a DVM on the Diagnostic port. When the engine is warm and both O2 sensors are working normally the ST fuel trims seem to be good.

Dropping the exhaust looks like a nightmare. It would have to be split before it crosses above the frame rail.

 

[Rifleman]

Dropping the exhaust looks like a nightmare. It would have to be split before it crosses above the frame rail.

Here's how to do it, First jack up the truck and support it on jack stands, next disconnect both O2 sensors, then disconnect the exhaust where the head pipes connect to the exhaust manifolds, Next place a floor jack under the exhaust system to support it's weight,

Then disconnect the hanger clamp on the exhaust pipes in the engine bay on the passengers side firewall, Last unbolt the exit side of the cats from the Y pipe, and lower that part of the exhaust system out of the truck ,

 

[Rifleman]

The outboard stud of the outboard sensor is dust, nothing remains there is something on the inboard stud but not much.

This is all the more reason why you're going to need to remove the exhaust system so you can repair those missing O2 mounting studs

 

[BTLSHP]

This is all the more reason why you're going to need to remove the exhaust system so you can repair those missing O2 mounting studs

Yes, not wanted I wanted to hear, but what I fear. Oh well, I am doing the front and rear hub bearing next week anyway.

Ironic because the lower

portion of the body mount at the forward "Y" has basically perished. I have the replacement and have been curious about how to get it in place.....

 

[BTLSHP]

...and, of course, if I knew I were dropping the Cats I could have replaced the rear most heater pipe section with real pipes not hose.... Oh well.

 

[Rifleman]

Yes, not wanted I wanted to hear, but what I fear. Oh well, I am doing the front and rear hub bearing next week anyway.

Ironic because the lowerView attachment 3704095 portion of the body mount at the forward "Y" has basically perished. I have the replacement and have been curious about how to get it in place.....

Oh man i didn't know you had a rust problem, i hate working on anything that has rust!

 

[BTLSHP]

I find the rust assessment very subjective. That is by far the worst body mount and I attribute that to the heat in the area as well as corrosion.

I am going to focus on protecting smaller brackets underneath and then perhaps Nuoxudol or similar. The body has one spot on the Pax inner fender liner where the forward mount for the air cleaner rests. That is basically it. I cleaned the fender liners well in the engine bay and used Q-Tips on the threaded holes which are rust free. Then without much thought I lightly scuffed the area with #600 and sprayed on several coats of clear coat. Who knows?

I am going to look at the exhaust more closely in the morning. Pretty certain the front will come off reasonably, it is the rear section that worries me. Bit if I have to drop it, I will re-evaluate the rubber hoses I ran to the rear heater and perhaps just buy the metal lines and re-finish them per @Kernal 's suggestion.

 

[BTLSHP]

I was able to disconnect the O2 Sensors to test them. The outboard sensor has an open heater circuit. So, I have ordered a new NTK that will arrive Friday.


I would appreciate thoughts/experience, but visually I think this one is accessible without dropping the exhaust. I will have to remove the heat shield and at least the forward running board bracket if not the running board, this is what I will be confronted with:

- Soak in what between now and then? PB Blaster and/or naval jelly
- Try and melt wax into threads?
Then:
- Nut extractor or splitter? The lower nut is mostly gone.

Thanks

 

[BTLSHP]

I have found this P/N for the flange nuts, 90179-08059

Does anyone know the gasket part number offhand? Tried to find a parts diagram that include th sensors and could not.

 

[jonheld]

I have found this P/N for the flange nuts, 90179-08059

Does anyone know the gasket part number offhand? Tried to find a parts diagram that include th sensors and could not.

O2 sensor gaskets: 89466-20020
O2 sensor nuts: 90179-08101
O2 sensor covers: 89437-60030

For exhaust hardware, I use Loctite LB 8023.

 

[BTLSHP]

O2 sensor gaskets: 89466-20020
O2 sensor nuts: 90179-08101
O2 sensor covers: 89437-60030

For exhaust hardware, I use Loctite LB 8023.

View attachment 3705278

Thank you - totally different diagram than I was finding.

 

[Rifleman]

I was able to disconnect the O2 Sensors to test them. The outboard sensor has an open heater circuit. So, I have ordered a new NTK that will arrive Friday.


I would appreciate thoughts/experience, but visually I think this one is accessible without dropping the exhaust. I will have to remove the heat shield and at least the forward running board bracket if not the running board, this is what I will be confronted with:

- Soak in what between now and then? PB Blaster and/or naval jelly
- Try and melt wax into threads?
Then:
- Nut extractor or splitter? The lower nut is mostly gone.

Thanks

View attachment 3705158

After looking at the condition of the O2 sensor nuts in your photo, i think the only way you're going to be able to remove them is to drop your exhaust system,

Now I've been wrong before, but seeing as the nuts have ZERO flats left on them, i don't see how (or what type of tool) you're going to be able to grab a hold of them with from underneath the truck,

As for what type of deep penetrating oil i would use on what's left of those nut's, I'd try using some 50% ATF mixed with 50% acetone,

 

[BTLSHP]

After looking at the condition of the O2 sensor nuts in your photo, i think the only way you're going to be able to remove them is to drop your exhaust system,

Now I've been wrong before, but seeing as the nuts have ZERO flats left on them, i don't see how (or what type of tool) you're going to be able to grab a hole of them with from underneath the truck,

As for what type of deep penetrating oil i would use on what's left of those nut's, I'd try using some 50% ATF mixed with 50% acetone,

I have acetone & ATF. The O2 Sensor won't arrive until Friday and I have to leave town Thursday. So, I am going to try to soak the nuts this week and see if moving the heat shield and running board out of the way to see what the access is like. I am going use a bit of a mild acid on the rust and then your acetone/ATF mix.

I can probably manage the task of dropping the exhaust. The forward section is fine, the downpipes are done 5 years ago.

I never worry about advise being right or wrong from this group. I know all of it comes from people willing to help and we (my family) really appreciates the assistance. We know my father (the original is slipping at 90), there is nothing more he would like than to see his favorite car end up with the real outdoors person in the family (my daughter). IHMUD is making that happen.

PS Are there any tasteful IH8MUD bumper or window stickers around?

 

[Brindleboxer]

Wishing you luck with the exhaust.

Here are a couple links for "tasteful" mud stickers.

Pink IH8MUD.COM Sticker

Postage included This is a one piece vinyl sticker Easy to install Will make your Cruiser way cooler……and you didn’t think that was possible did you…

www.ih8mud.com

IH8MUD

IH8MUD - The online bible for Land Cruiser owners online Merch Shop.

reefmonkey.com

 

[BTLSHP]

Well, I have ben chipping away at this in between bouts of frustration with the rear parking brake/axle work. Here I have had a bit of success. I took off the running board and since I have painted once in a while, I will scrap and paint again. This gave me access and I went at the studs with mild acid and acetone/transmission fluid. Then I got out a wire brush and the lower stud all but cleared itself. The upper stud came clean with help from the edge of a small cold chisel. I literally unwound metal from the threads.

So, the sensor is free. I do n0t think any threads were damaged with the chisel as it was resting on the gasket plate and directed at little nubs of the rusted bolt. It is pretty clear that there is still material in the upper threads.

How do I remove this?

a

 

[BTLSHP]

The new O2 sensor arrived. My remaining issue is the bits of rusted nut threads left in the studs. I can't thread a nut past the residual. I have wire brushed the studs with moderate force - I am worried about debris going into the exhaust. I have also tried to pick with a pick tool.

Is this a job for a re-threading die? Not a lot I found on Youtube

Also, the original sensor wire has a little body plug. Is this some thing generic of is it unique to Toyota.

Thanks,


I found out there are little shields for the O2 Sensors, are these important? Should I replace them?