If you are having fuel consumption issues, changing your AF sensors may help with your mpg. Prior to attempting that, ensure you dont have any air leaks between your MAF sensor and the throttle body or any other vacuum leaks. Unmetered air might be telling the ecu to dump more fuel.

 

Great DIY, thank you for taking the time to do it! So my 2004 RX300 with 160k miles on it popped a CEL requiring me to change the bank 1 sensor 1 A/F sensor. I did that using this great DIY write-up, but 6 months later I got a CEL p0135 AGAIN popping up saying bank 1 sensor 1 A/F sensor is bad. I will try cleaning the MAF and put in a new air filter, and test the other sensor, but in case all those are normal and I still pop the CEL again, what could be going on?

Something upstream leading to damage/contamination to the A/F sensor?

Thanks for your help guys.

 

Hi 83corolla et al,

I know this is a very old thread, but just a heads-up on the pic that you attached of your new sensor's box:

The box end label correctly shows Denso P/N 234-9009 which is the right number for the Air/Fuel Sensor. However, that box incorrectly shows "Oxygen Sensor" on the box long side, which is not correct. I know for a fact because I have the same Denso P/N 234-9009 box, and it is correctly printed Air/Fuel Sensor on the box long side. HTH.

Btw, my new Denso P/N 234-9009 (on the box) has these numbers on the part itself: 192400-807O (yep, that's a Cap "O" as in o-ring), then 04S01 under that.

Btw, My job was the sensor up front (bank 2 sensor 1). Didn't even have to get my tee shirt dirty. The hardest part was getting the electrical connector off: I removed a little ring that holds some spark plug wires in place above the sensor, moved the wires back against the engine, and this allowed easier access to the connector from the top down. I finally used some very long needle nose pliers to depress the latch lever (without cutting the shielding on the engine side of that connector). If your hards are strong enough, you might just be able to squeeze/push down on the latch lever with your fingers, while wiggling and pulling out on the plug and sensor wires.

I hit the old sensor threads with PB Blaster about half an hour before taking a 7/8" box end wrench to it. I read elsewhere that overnight is even better. Wrench is 12" long overall, and the top of the wrench was just able to slide under an AC line that's on the evaporator. I wouldn't want to try with anything shorter. I had to pull on it pretty good to get it turning.

Helpful thread. Thanks :-)

Regards . . .

P.S. Off-topic: A new topic in a forum is called a thread. Replies to the original poster's thread are called "posts" to the thread. So we could say, "I logged into Club Lexus made a new thread about sensors, and several people have made posts to it since yesterday". It's a bit confusing, but that's forum history.

 

Well, I've been watching this thread and others here on CLF and have learned much. About 50,000 miles ago I replaced two of my sensors successfully. Recently got the dreaded p1150 code along with p0172. Replaced the bank 2 sensor 1 A/F circuit, but still got the code. Replacing the Bank 1 Sensor 1 today. Hoping for the best. As I recall, last time I changed one, but still got codes and they didn't go away until I replaced the second. Not sure if only doing one (on the front side of exhaust) just screws up the mixture and computer, but eventually remembered what happened last time. Will let you know what happens. By the way, my box also says air/fuel sensor on the side.

 

Hi mikecd1,

I replaced the A/F sensor on the rear header on 1/14/2013. That's a little over 3 years ago. No A/F sensor codes since then until a couple months ago (when I bought the new Denso part but did not install until a couple days ago). This time as previously mentioned, it was the one on the front header. I don't recall this fact about the first one, but this time I did pull that ECU fuse for over an hour, but I still had the engine light on and the codes still showed also after starting the engine. Read on please.

I'm using The paid version of Torque (on Android) and an authentic bluetooth enabled "ODB Diagnostic Interface" (from BAFX Products) to read the codes. That software has a "Clear Codes" function. So . . . I did a Save to save the current code(s) for our future reference, then I did a Clear Codes. The codes in Torque and the dashboard engine trouble light immediately went away. Since then, I had a 60 mile road trip at sustained speeds up to 65mph, and no codes have reappeared (yet :-) .

Regards . . .

 

Just as an update, after replacing S1B1 and S1B2 I am happy to report that codes have not returned and the car is running great! Drove about 20 miles although yesterday was 55 degrees out and today is about 32 degrees. We'll see how she weathers. Also cleaned the MAF sensor along the way so hopefully this is a nice fresh start for my baby. Thanks to all for sharing info. This has been a great resource for me over the years.

 

we replaced B1S1 this weekend and had the hardest time opening the connector - we ended up disconnecting the harness bracket/clip (10mm socket) reaching in from above, and opened the harness bracket to rotate the connector (from below) - finally were able to open the connector from beneath the car

we also found that the wiring harness insulation leading to the socket was crumbling (>160K miles), so releasing the harness out of the bracket/clip allowed us to wrap the wiring harness with new insulation before reinstalling it in the bracket again and bolting the bracket down

 

I had one heck of a time by myself trying to detach the connector because of the lack of room for two hands above or below the sensor. I took a long slotted screwdriver and placed it in the notch of the connector. I had my wife turn the screwdriver clockwise slightly while I got under the car and pulled the connector free. It was a piece of cake to disconnect with another person there!

 

Thanks 81Corolla for the write up. I just ordered parts from Amazon to replace the B1S1 sensor on my 2002 RX300 that I just bought.

 

Thanks for the DIY Unplugging the sensor near firewall was the tough part. FWIW I unplugged it from the top. Right hand through the gap by the throttle body ( to push the release ) Left hand under and behind the PCV (to pull the sensor plug. ) to make it easy I disconnected the hose to the PCV valve for more room. Hope this helps someone!! After that it was a piece of cake with the DIY and sensor socket. Also test your sensor (old one ) when you remove it and the new one before you install to save confirm your OBD codes were correct. Best to all!

 

Earlier in this thread it said "the Lexus part number for the RX300 air/fuel sensor is 89467-48011. The OEM a/f sensor is made by Denso and the Denso part number is 234-9009. The two are equivalent." but in an other thread it recommended to only use Denso 234-9009.

I'm am buying a 2002 RX300. The privies owner has been running for several years with the check engine light (CEL) on with codes of P1135 and P1155.Basically the heater circuit in the Air Fuel sensors are not working which isn't effecting the running of the car (at least after it is warmed up . My problem is I can not pass an E-check with the CEL on.
I ordered two Denso 234-9009 sensors. I received two Toyota - Denso 89467-48011 sensors (# stamped on the part). I decided to use them any way.
When installed the CEL codes went away but the RX300 ran very poorly, very rich.
Now I am confused. Did I receive bad parts or do I really need to only use Denso 234-9009 sensors?

 

I dont want to sound as if I am lecturing, but why would any one buy a vehicle with CEL on. The previous owner had plenty of time to have it checked and repaired. I see two possibilities
1) The previous owner does not care about the vehicle
2) The previous owner tried to have it repaired and the issue could not be resolved or the real repair costs too much.
Either way it an indication of keep away.

After the change, did you reset the computer [disconnect the battery for about 20 mins]? Then I would suggest waiting it out till you get another code, or hook up to a live diagnostic tool.

Salim

 

The mechanic that has been servicing the RX300 since it was out of warranty is a certified mechanic that has worked for my father-in-law for many years (his best mechanic and the brother of the owner). The CEL codes P1135 & P1155 indicates the sensor's heaters were bad. This only means the sensor take longer to reach optimum temperature. The car still runs fine. He could not see spending $200 - $400 per sensor just to turn the CEL off. They do not have E-Check in their area, but we do.
The new parts did turn the CEL off but the car ran very poorly.
I do not know if he reset the computer or not. All I know is he took the new sensors back out and I returned them.
I did not see the post about the 234-9009 and 89467-48011 being equivalent until after I sent the parts back.
I got the parts from EBay for $46 each. The packaging was suspicious with no identification and it did not have the 234-9009 part # on it anywhere.

I want to insure I order the correct parts for without spending $200 each.

 

Best thing your mechanic can do is order parts through online Lexus parts. Provide them with the vin number and you are guaranteed that you are getting a genuine part. I have made purchase from Bell Lexus AZ and also from Lexus of South Atlanta. Price them out, you may be pleasantly surprised. With so much grey market stuff, you are taking a chance.

Keep in mind, usually, one sensor dies at a time. There may be something else going on. Glad that you have a competent mechanic working on your vehicle.

Salim

 

$46 sounds way too cheap to be a real OE or Denso sensor. It sounds like you probably bought fake knock of parts that didn't work well. Order new Denso parts from Amazon or Advance Auto (Advance Auto will price match Amazon) and see how it runs. You should be paying around $100 - $120 each. Most of us just use the Denso part because it works perfect and is 1/2 the price of a Lexus/Toyota OE part.