P0138 code

TOKITAN

MEMBER
2010 TOYOTA COROLLA
1.8L
4 CYL
2WD
AUTOMATIC
314,000 MILES

First time I have p0136 and p0138 codes I changed downstream o2 sensor (denso), clear code. Light coming back p1201 and p0138 codes. Then I change to Toyota OEM part o2 sensor, clear code. Light coming back show only p0138 code now. Can I fix this myself? Previously I was having the Toyota dealer to install and I pay the labor charge only. I do not want to pay diagnose fee ($136.00). Today I drop off to my close mechanic near my house, they said bring it to dealer to reprogram the computer due to your sensor high voltage. Please teach me how to fix it with myself?

5 Replies

JOHNNYT73

MECHANIC
924 POSTS

From the research I have found is that this issue is only corrected by the dealer or if you find a shop that has the equipment and knowledge on how to calibrate the PCM (power-train control module). There is known issue that Toyota is aware of with this code. You replace the sensor and you must also install a new software in the computer. Here is the TSB# (T-SB-0066-10).

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Wednesday, February 7th, 2018 AT 5:44 AM

TOKITAN

MEMBER
3 POSTS

If my p0138 is not really trouble from o2 sensor? Then I should reprogram the ECM again? How much the dealer charge approximately? Dealer will need to diagnose first right to fix your problem. How do I check my sensor cable or connector are short or not? My fuel injector insulator is leaking could it be from this cause? Thank you. I already purchased catalytic converter cleaner. It will take one week to arrive. I am going to try it out. Please give more advice and store recommend even New York is okay for me.

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Wednesday, February 7th, 2018 AT 6:28 AM

KEN L

MASTER CERTIFIED MECHANIC
47,207 POSTS

Hello,

I would check the wiring and connections first. Here is a guide and the engine wiring diagrams so you can run tests:

https://www.2carpros.com/articles/how-to-check-wiring

If the wiring checks out you will need to have the PCM reprogrammed for about $130.00.

Here are the engine wiring diagrams.

Check out the diagrams (below).

Please let us know what you find. We are interested to see what it is.

Cheers, Ken

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Friday, February 9th, 2018 AT 11:32 AM

TOKITAN

MEMBER
3 POSTS

Ken, are you mean if I use multi-meter to check the wiring I will need to reprogram the PCM by dealer?

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Friday, February 9th, 2018 AT 9:07 PM

KEN L

MASTER CERTIFIED MECHANIC
47,207 POSTS

Sorry, I mean you can check the wiring and it is okay you will need to go to the dealer to have the PCM reprogrammed.

Please let us know what happens.

Cheers, Ken