I recently replaced the A/F Sensor after the CEL codes read P0125, P1133 and P1135. I bought this 99 ES300 from my uncle about a year ago. He was the original owner and kept EVERY service receipt. I dug through the records and found where he had the A/F sensor replaced numerous times. The last being in June of 2016. This is exactly what I just replaced in the vehicle. More searching found that he replaced it in 2015 as well. What in the world would cause the A/F sensor to fail so many times?? The codes were cleared and would not reappear for several months. Thanks

 

What brand parts were used?

 

The one I pulled out was a Denso. I replaced it with the same thing.

 

I don't know what think, can't imagine bad wiring or even a bad ECU killing the sensor. Exhaust getting too hot?

 

Not where I notice anything unusual. I never see smoke.

 

That is weird. Was it an eBay "Denso" or something from a known/trusted outlet like RockAuto?

 

I think I got it on Amazon. If not, eBay. One of the 2.

 

Oh, okay. It's a crap-shoot on eBay with fake "Chensos," and Amazon's having problems with fake parts as well (personal experience with Amazon, sellers sold me fake VVT solenoids).