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Discussion Starter #1
While setting the emissions monitors for inspection I got a pending p0136. This morning I was able to get the catalyst monitor to set with the pending P0136 code. After first seeing this code pop up I checked the connections to the sensor. It was wet due to just pressure washing the engine bay. Anyway I dried it out and tested the sensor with propane and multimeter. Voltage would climb with heat but would drop off quite quickly when heat was removed and even while gradually trying to reduce the temp.

Anyway I finally got the o2 monitor to set after coming to a stop. So I turned around and headed for an inspection. The first stop I made after turning around the CEL came on for P0136 Bank 1 sensor 2 circuit malfunction. Fuel trims are as follows.

STFT B1 -5.4
LTFT B1 13.2
STFT B2 0
LTFT B2 11.7

Does this indicate a failed or failing sensor or another problem?
 

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Discussion Starter #2 (Edited)
Few more things to add. I checked the exhaust for leaks and didn't notice any. I was checking the sensor output with vehicle idling. I don't get any voltage at idle. Minimal rise while revving. I threw a 2nd P0136 code from having the sensor unhooked. This tells me its functioning to a degree, but probably toast.

I find it odd that the catalyst monitor will set to ready indicating the o2 sensor is functioning, but the sensor faults out when its check runs.
 

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Discussion Starter #3
Still waiting on a sensor to arrive in the mail. I hope this fixes it. I see this problem quite often and nobody seems to post a remedy. I saw one or two posts where a new sensor fixed it. Others don't seem to ever reply.

Finally off work for a few days. I'm going to be poking around for a pin hole exhaust leak. I really hope I find one so I can get inspected.

I guess these Toyota sensors are very sensitive. I had a 2000s chevy truck once that blew a cat out the tail pipe due to a faulty fuel regulator. I actually pinched the louvers in the sensor closed, the light turned off and never returned. Wish this was that easy.
 

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Discussion Starter #5
Thank you. I saw you posted this in a recent p0136 thread. Just now I soaked the sensor it in carb cleaner. Blew it out with compressed air. Heated it up with propane and repeated this a few times. I'm getting higher readings now with it off the torch cooling. A less rapid drop in voltage than before. I think the ceramic was real dirty. I don't know if this is a fix yet, but the readings are much steadier than the last time it was heated up.

With the catalyst monitor set I know the sensor is partially working. Its just not sensitive enough at idle. Also, there doesn't seem to be an exhaust leak anywhere.
 

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Discussion Starter #6
Update on this situation. I may have found the fix on my car, but it hasnt been tested yet.

The farthest left two exhaust manifold studs were loose. The farthest left one was barely hand tight and wasnt touching the flange. The next one over got a 1/2 to 3/4 turn to snug it up. If there was an exhaust leak that was it.
 

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Discussion Starter #7
Well this fix didnt fix the code. It did however bring the fuel trims very close. I'm happy about that. Sensor is in the mail. Hope it works.

B1ST -6.7
B1LT 3.1
B2ST -7.1
B2LT 3.1
 

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Discussion Starter #8
79539

79538

I did a detailed inspection of the underside of the manifold and noticed some soot. I proceded to saturate with soapy water and started the motor. There were bubbles on cylinders 2 3 and 4. So I pulled the gasket.

I will pick one up tomorrow at the parts house. Currently I have three of the studs soaking in panther piss to free the nuts off before install.
 

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Discussion Starter #9
Ok. This time I think I figured it out. Someone soldered on a pigtail to extend the o2 sensor connector. The signal wire on the factory pigtail has a ground running through it along side the signal to filter out noise. The splice at the bottom of the signal wire and ground/filter wire were heatshrinked together. So the signal wire was grounding out. When I removed the heat shrink and separated the two the main signal no longer gets ground.
79546
79547
 

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Discussion Starter #10
The saga continues. Luckly this wiring repair fixed my o2 monitor. The o2 monitor set within 10 minutes of driving. A new record. Only this time the catalyst monitor was taking a while. Eventually it threw a pending p0420. Not sure if its a fluke or an actual problem. I guess I'm glad to see another code. At least my o2 sensor is working now.

I wont be able to check on this until next week. I have another cat I can weld in, but I would prefer a short term solution like an antifouler or one of those mini o2 cats.
 

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Discussion Starter #11
Solved. This morning I picked up an anti fouler set. I drilled it out to 1/2". Stacked the two foulers and screwed in the sensor. For reference there is about 1/32nd space around the sensor in the top fouler. I did clear the codes on the way to get the anti fouler because light came on for p0420. When I got home it had set a pending p0420. I screwed in the setup and went for a drive without clearing the pending code. Within five minutes the o2 monitor set to ready. I kept driving to see if it would end up throwing a code. After about a 60 mile round trip into town no codes were set. The pending p0420 cleared itself. No DTCs present and all but the evap monitor ready. I can get inspected tomorrow. This was a real success. 🏁

As long as they dont stick one of those probes up the tailpipe I will be good. I don't think this car requires that in Texas, but with the other surprises who knows. I didn't check to see if the cat was intact. I do know that within a 20 miles the o2 sensor is carbon black.
 

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What is the oil consumption?
 

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Discussion Starter #13
I'm not entirely certain at this time. I'm estimating half quart per 1000 miles with various leaks.
 
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