Good Morning, and I have a Lexus ES300 with 221,000 miles that runs like a top. The check engine light has come on. I was told it was the oxygen sensor that needed to be replaced, which I did for about $150.00, only to have the light come back on a month later. Now I am told that it is the catalytic converter that needs replacing. I am told that only an original Lexus unit will solve both the emissions issue, and also make the light go out. An after market cheaper unit, I am told, will solve the emissions issue, but not the light.My car looks original, and I want the light out. A Lexus catalytic converter costs $1,450.00, with installation extra. Any ideas, and thank you.

 

do a search on "oxygen sensors" and you will find many threads. Bank 1 Sensor 1 is the harders to get at. It is between the cylinder head and the cat. on the rear bank of cylinders. It is a tight squeeze to get your hand in between the exhaust manifold and the firewall.

The sensor will cost over $200 from the dealer and then another 1 to 1 1/2 hours in labor (at close to $100/hr.) if you have it done at Lexus. A toyota dealership may be cheaper as the same sensors are used in many Toyota models.

The sensors can be had online for cheaper and you could do it yourself if you have the tools, time and knowledge. If not, seek out a reputable independent mechanic in your area.

When the trouble code (P1135) was read, they may have cleared it, thus the CEL being off. It may come back. The sensor may not be totally faulty, just on its last legs.

The last point I must make, is that the trouble code you get may not always point to the culprit at hand. Problems further upstream from the indicated trouble spot may trigger codes from different sensors. It takes a knowledgable diagnostician to figure it out. Replacing every part that every code points to can get expensive.

Good luck.
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Ratatouille
monster milk

 

I agree with the comment you made, especially the last para. In my case, I was told the CEL being on was due to the ECK valve, in particular the vacuum modulator (not sure what that meant). But if the diagnostics becomes a hit or miss thing it surely can be expensive.

I also have a 95 es300 which has given me a bit of concern lately:

I am noticing my temperature guage increasing (almost hitting the red mark on the H side) especially when I am driving in traffic. Just also noticed hearing a whining sound when I start accelerating from traffic, almost feeling that it might have something to do with the drive belt or sepentine belt.

Any suggestions on what to look out for?