Toyota tacoma 2010 P0138

[Julien Ste-Marie]

Hello guys, I have a 2010 toyota tacoma Sr5 with the 2.7L 4×4. I have 60000 miles on it.

About a year ago i started to get the p0136 code. After a few time resetting the DLC with no success to clear the codes for good( the codes kept on coming back after 60 to 150 miles ).
Not long after that i got both the p0136 and the p0138 codes, and for about 6 months i only have the p0138 codes. The p0138 is about the rear oxygen sensor that has a high output voltage.

I replaced my rear oxygen sensor with a brand new Ntk oxygen sensor but that did not the trick. I also tried some spark plug non foolers without any success either.

I noticed that the rear oxygen sensor stay at about 0.835v when i keep the engine rpm constant, but when i let go on the throttle the sensor voltage come down to about 0.15v and goes back the 0.835v. While moving with the truck the sensor voltage moves but not a lot, goes from 0.780V to 0.955V max but usually stays at 0.835V.

I have checked the wiring and I don’t see any problems, and the wires seem good.

I have the software Scan xl the read the Obd2 data. I will attach the freeze frame data from my last DTC p0138 code.

What could this be?
Could it be the sensor even though i changed it? May I should have bought a Oem Denso sensor.

Some help would be extremely appreciated !

Attachments:

• 2_freezeframe.jpg
• 1_freezeframe.jpg

Topic

[Its me]

First I always recommend Denso, but NGK/NTK are not usually a problem…. Bosch on the other hand… cause issues…

The OEM is Denso, and with that, I would recommend the OEM Denso unit and see where that takes you.

-Karl

[none]

[quote=”ToyotaKarl” post=132094]First I always recommend Denso, but NGK/NTK are not usually a problem…. Bosch on the other hand… cause issues…[/quote]

Thank you! I got a service writer that thinks everything German is gold. I have three Bosch sensors going into an Avalon tomorrow because he ordered the parts. I’m already anticipating warranty repairs.

[Its me]

[quote=”no_common_sense” post=132095][quote=”ToyotaKarl” post=132094]First I always recommend Denso, but NGK/NTK are not usually a problem…. Bosch on the other hand… cause issues…[/quote]

Thank you! I got a service writer that thinks everything German is gold. I have three Bosch sensors going into an Avalon tomorrow because he ordered the parts. I’m already anticipating warranty repairs.[/quote]

Wow…. That service writer doesn’t know crap about Toyotas…. I often hear “Bosch invented the the Oxygen sensor”, well that is true, but it does not make them work well with Toyotas… You are right about having a very good chance to see that vehicle again… Sorry you got a service writer who is a dolt…

-Karl

[Brandon Garner]

It’s hard to tell just from freeze frame. The freeze frames you provided look normal. Can you see live data? Do you have an infrared thermometer? The readings I see and what you have said do not indicate a bad cat, but it’s always safe to check. You already replaced and said you checked the wiring. I would also check grounds, then connections at the PCM. Seems like you are having an intermediate problem. Sometimes the terminals can be the fault. They are a spring metal and can sometimes loose their spring and not contact as they should. My advice is to follow the wiring and look for anything loose, rubbed, burnt, the obvious. Then checking the contacts at the PCM. Best way to check is just to compare the terminals to each other. Just my experience. Hope it helps. Report back when you do find the issue.

[none]

He’s actually a really smart guy in most cases, he’s just got this absurd blind love for German engineered anything. I’ll post back when my customer comes back with their next check engine light.

[Julien Ste-Marie]

Thanks for your reply Ipdwntnd I will try to recheck the wiring.

Yes i can see live data, what should i check for?

Like I said above when i check the live data the output voltage of the oxygen sensor varies from 0.780V to 0.955V and only comes out of that range when i let go the throttle. So in other words it’s stays around 0.835V almost all the time.

With the infrared thermometer what do you want me to check?

thanks

jstem4

[Julien Ste-Marie]

OK thanks Karl, I will look into ordering a Denso if that can solve my problem!

[Author]

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