1999 Avalon Check Engine Light - P1135 and P0125

[Saiki]

I have been maintaining my 99 toyota avalon pretty good. It has about 120k miles. I was surprised to see the check engine light come on yesterday :-(( I took for the bi-annual inspection just last week and it went thru fine!!

Took it to Autozone today and the gentlemen at the store said it shows P1135 and P0125. He advised that it should be looked by a mechanic. All I saw immediately was $$$ going out !!

What is wrong with the car and please advice if a local mechanic can deal with it or only a dealer. Any help is appreciated !!

Thanks.
-Sai

[pmesfun]

For P1135, bank 1, sensor 1, the O2 sensor needs to be replaced. Normal maintenance item, mine went out around 67k miles so you got a good life out of them. I would replace both since they are of the same age, and you car will perform MUCH better.
First replace teh O2 sensor because P0125 could be caused by the 02 sensor failure.

P0125 deals with the cooling system, ECT sensor could be faulty or thermostat is not operating correctly. Check for any loose connection around the radiator cap and the water inlet housing next to the starter. Does the engine normal operating temperature?

Without a doubt a local mechanic can replace all of these.
look at this thread for the location and how to get the O2 sensor out:
1995 avalon, need to replace O2 sensor, where is it?
Is you Avalon California or Federal Spec, its noted on the vacuum diagram in the engine bay.

[Saiki]

Thanks for the prompt reply.

I will take it to the local mechanic. Now that you have given me guidance on the issue, I will be able to "converse" with the mechanic.

Hopefully it gets fixed. I will post an update once I get it fixed.

Thanks again.
-Sai

[pmesfun]

Originally Posted by Saiki

Thanks for the prompt reply.

I will take it to the local mechanic. Now that you have given me guidance on the issue, I will be able to "converse" with the mechanic.

Hopefully it gets fixed. I will post an update once I get it fixed.

Thanks again.
-Sai

Sounds good, make sure Denso O2 sensors are used.

[Jack Deth]

been there, done that...
For the record : P0125 & P1135

[Saiki]

Originally Posted by Jack Deth

been there, done that...
For the record : P0125 & P1135

Thanks to one and all who diligently replied to my post.

My local mechanic was able to fix the issue. Ad you guys rightly pointed out... for P1135, bank 1, sensor 1, the O2 sensor had to be changed. He said the other code P0125 is also an "offshoot" of the same issue and it should go away once the O2 sensor was changed.

Didn't take risks -- asked the mechanic to put in genuine Toyota sensors $245 and the total cost including labor was less than $300. The car has been running smoothly for over a week now.

Only thing I wanted to know was should I have changed the other 2 two also? What benefit would I get (or lost) since I did not change the other two?

Thanks a bunch!!!
Appreciate all of you guys... you are a wonderful helpful bunch..

-Sai

[pmesfun]

Which sensors were changed?