techiedude

I'm getting a P0135 error code on my 1996 es300 with 95,000 miles.

The code says
It seems that bank 1 sensor 1 is between the engine and firewall, so I guess I know which one to replace, but I bought a Bosch, and I guess Bosch is not recommended. I have all the tools and jack ready to get started. I was going to go back and get a Denso, but a guy in another thread said I'll fry it, and I should use an AFR senor instead. I went to the Denso site and looked for replacement parts. Searching for either O2 or AFR sensor points me to O2 sensors. I called Lexus and the woman said it's definitely and O2 sensor. I did some googling and I see that AFRs are wideband, but I don't see anywhere that I can replace an O2 with an AFR. The guys at the auto store tell me I should not use an AFR.

Anyone know why he's telling me to use an AFR and that I'll 'toast' an O2 if I use one? He hasn't replied, and his replies are so short they are not of any help anyway. He has 6000 posts though, so he may know something, or maybe not. I have the afternoon off and now I am not sure if I should go ahead with it.

Can I, or should I replace an O2 sensor with an AFR sensor?

thank you

Power6

Hey I'm a n00b here but not a n00b in general. Hard to say what the advice you got about AFR and O2 sensors is about, but any distinction between those two is generally a "lingo" issue, all "AFR" sensors are O2 sensors. This is how they work, Oxygen content of exhaust gas is sampled, and based on the results the air-fuel ratio (AFR) of combustion is determined. For the purposes of accurate AFR a "wideband" O2 is needed. Any "narrowband" O2 is only useful within specific parameters so one might not call that an "AFR" sensor. In general old cars use narrowband sensors and newer cars use wideband sensors, but it gets complicated from there.

Really what I think you want to be concerned with is getting the right part compatible with your car. I wouldn't be concerned about what it is called or whether it is a wideband or narrowband. Just get what is specified for your car. If you want to try the Bosch put that in, or otherwise get the Denso.

techiedude

Thanks for the reply, sir!

MattieVSS

Traditionally with Toyota vehicles in general, the "Air-Fuel" sensors are before the Catalytic converters and the "oxygen" sensors are after the Cat

Power6

Thanks for the Toyota lingo lesson, good to know!

Hayk

iTrader: (1)

It's not just a lingo issue. Wideband sensors are AFRs, narrowband are O2's.

I know for the 3rd gen ES, if the car is California Emissions Certified, then it uses AFR sensors before the catalytic converter. If it's not a CA certified car, then all the sensors are O2's

techiedude

Wow, it sure is hard to get at the thing -- both from above, and from below. No luck yet. I can barely get a wrench on it, let alone move the wrench.

From above is a little easier, but too many tubes and hoses to damage. Is there some trick to this? That split socket tool doesn't look like it would be any help. Maybe I'm supposed to take something off to open the area up.

Hayk

iTrader: (1)

There is a thread on here somewhere for sensor removal that you're dealing with and it just so happens that the person had a 2ES. I'll try to find it, but look around yourself as well.

EDIT: Here you go. Seems like the trick is in having the right tool.
https://www.clublexus.com/forums/es3...00-w-pics.html

Power6

Maybe to you there is a distinction, but the terms are rather interchangeable, though most would say "wideband O2" not to be confused with a narrowband.

I'll shut up now and not be THAT new guy ha

techiedude

Thanks, yeah, I think he has less stuff back there than I do. His engine looks more open. But thanks for taking the time to dig that up. I did go searching after your post, but couldn't find any tricks, or other tools except a guy who cut a box wrench open. That might be nice to have, but it seems like there's no room to swing a wrench.

I took it over to a repair shop and the guy put it up on the lift. It looked less difficult to work on that way (than laying on my back). I have to figure out how to get it lifted up higher in my garage. (it was too hot to work on at the mechanic's, and I couldn't wait for it to cool down).

Hayk

iTrader: (1)

I'm still learning about the difference between the two, so I really appreciate the feedback. That wiki page was very helpful as well. Now how can you tell one from the other without a scanner? I think one of mine is bad, but I'm not 100% sure if it's a narrowband or a wideband sensor.

Power6

Outwardly the sensors look similar or the same, the technology is much the same. Whichever sensor a car uses is whatever it is designed with. Of course as time goes on, newer cars, emissions and economy concerns have made the wideband sensor a given on newer cars.

Usually I learn from service manuals or message boards this sort of info. I haven't owned a car as old as the 2001 ES300 I am picking up tomorrow in some time, I've no idea if it uses an old school narrowband or the more modern wideband sensor!

Also note any OBD II car will use a second, typically narrowband sensor behind the cat, which performs a different function altogether, it simply verifies the catalytic converter works properly as required by the OBD II regs.