Cel codes, 0138 and 0606

So I gotta say first time in 7yrs and 130k by me, my truck has thrown a cel light.
I was also just hitting 173000 on odometer.
I’m thinking it was a quirk.
We’ve had 20” of snow and -10 w/-35 wind chills.
Now it’s 50 degrees raining and storm drains are all frozen so a lot of water on the road.
I got the light minutes after leaving work, stopped at the beer store and got gas for both of us.
Restarted truck light was still on.
Looked at the codes took pics and cleared them.

Drove the 20 miles home without the cel returning.
Frame was done about 8k ago but I have had no issues with swap at all.
Just curious if should be looking at cats or a pcm maybe?
Not super worried, it’s prolly not coming back.
But she could have something going on.
If it returns I’ll crawl under and look at wires and connections.


2008 AC bsp
4 banger base
5 speed MT
170k

 

It’s back I’ll replace the sensor and see what I get.

 

Jeff, I think this thread will help with the P0138 and P0606 codes, as it solved it for the person who started the thread with the same codes. Here: https://www.tacomaworld.com/threads/help-with-code-p0606.356734/

If that thread doesn't solve your codes you can try what worked for this person: This person posted his solution on a 4.0l Tacoma, so I don't know if it will fix yours but here it is: Just wanted to post how I fixed my truck. The check engine light came on for p0138, so I replaced the sensor. Next day light was back on. My wideband afr sensor was reading 13 the whole time, so I pulled it out and checked to make sure it was working properly. Once I new the sensor was working I figured let me swap air fuel sensor from bank 2 to bank 1 and see what happens. My wideband afr went back to reading 14.7 or so at idle. Being I just spent almost $300 On sensor I was hesitant to keep changing them out if they were still good. So I installed the new one and everything is fixed now. No more check engine light. So if you have p0138 code and a new sensor didn't fix the problem, check the air fuel ratio sensor. Mine didn't throw a code for that sensor, but that's what was causing my bank1 sensor2 to throw a code. Hope this helps anyone with 2 generation Tacoma 4.0 v6.

Edit: This person who is a professional mechanic also had some good advice: So Toyota's have a thing about high voltage to the downstream O2 sensors, often it's caused by erroneous readings from the upstream A/F sensors.

It's more of an issue with the 3.5 2GR's but it can happen on any engine.

That said, one code is high voltage (which we usually suspect the A/F) and one code is opposite bank low voltage (we suspect the o2 sensor itself)

The sensors are faulting because they are working, just not in the perimeters set by the ECU. Also if the cat was failing you would have P0420 and P0430 associated to your o2 codes. If they were plugged you'd have a misfire and lack of power.

I would need a freeze frame for any further advise, I'd need to know voltages of all the sensors and the fuel trim on each bank.

You're gonna need them to look at it.

 

Yea I’ve read up on them since.
Always gotta go for the worst case lol when it comes to the truck.
I have only 2 sensors and I actually pulled the bank 1 #2 and cleaned it.
I used a scope to see what the end of cat looked like. I’ve been thinking I’m not getting back the oil I put in at oil changes so thinking or over thinking I’m figuring my cats getting plugged.

This is what I saw.
I’m sure it doesn’t mean much but looks pretty clean to me.
I cleaned the sensor and tried clearing the codes.
It would just come right back.
Now I’m thinking I made it worse.
Disconnected the battery for 20 mins and no more cel.
A/F is good and 3.2 on 1 and no more than .8 on 2.
I’ve done some miles let it idle etc while it relearned and it hasn’t returned yet.
I have both sensors in the cart ready to go.
I will get denso brand and have copper never sieze already.
I still wonder about the cat.
I’ve read the downstream should be hotter and my sensors show cooler on downstream end by like 50 degrees.
I will get a temp gun at work and see what I get with that.
I watch @TYetti ‘s build and he is in process of rebuilding because of oil rings.
Appreciate the help!
Funny I just got over stressing about the frame.
Got a new one!
And now I’m on the my rings are bad. Checking the dipstick for like the second time since 2011 between changes never really worried before.
Maybe 1/2 a quart not really sure where it was to start.
Tyetti suggested I pull the plugs to look for oil build up on plugs and pistons, and I plan to do this as soon as it gets warmer.

Thanks bud!

 

Just a thought but generally when temps are hotter before the cat an cooler after it's cause they're taking longer to move through the cat

That probably doesn't help

 

How did your cat look?
Could you see it was plugged.
I was thinking it would be darker at least.

 

It's pretty black I haven't had time to cut it open yet

 

Well no light so far.
Hard to believe I got lucky and cleaning seems to have helped it.
I’m gonna pull the a/f also and clean it to.

 

Jeff, any updates I have been reluctant to ask, after reading the previous threads I linked to with the same codes and the person doing the same as you, only for the CEL to come back? (how many miles have you driven since you disconnected the battery and cleaned the sensor?)

 

So I have about 400 miles since and no cel.
So far so good!

 

So the code returned yesterday.
My obd showed high voltage bank 1 sensor 2. No battery disconnected this time I was able to clear codes.
New senors will be here tomorrow.
Plugs eta not sure.
I will post pics when I do the plugs.
But with reading about cats and bad rings and valve seals plugged cats etc.
I’ve noticed I really don’t get the cat hot enough to work.
Not sure but I’ll post some cylinder pics when I get plugs.

 

So I changed both sensors this am and did oil changes.
I was only missing a little over 1/2 quart at 3k.
Got a pic of the front of the cat.

Thinking I’m over thinking it!!
Or so I hope.
Also the cel did not return after being cleared the other day.
Plugs will be next weekend seeing they didn’t make it here on time.

 

So I’ll post this here.
Thinking maybe oil rings are sticking weak maybe.
I did BG epr before last oil change.
Shit was black as black but still liquid after a week in the below freezing. No sludge and no metal at all some sand like shit very little, maybe from the pan?
I used chevron Techron seemed to help maybe?
Used

$24 BG44k BG 44K Fuel System Cleaner Power Enhancer 11oz.

BG44k and damm really seemed to do something.
I bore scoped my piston crowns before and am hoping to do it again this weekend.
Figure I’ll clean both sides of the rings.