99rx300wht

I pulled code P1133 on my 99RX300 and wanted to ask for input before going to buy a new sensor. After a call to Advanced Auto Parts, it seems this may be a part I can only get from Lexus. Is that true? I really haven't noticed any real issues other than slightly reduced fuel economy.

Also, sometimes, the car doesn't want to shift into overdrive at times, but if you stop, put the car in park, then put it back into D, it will start shifting into OD. The service guy at the dealership said this could be a switch that is worn (supposedly happens to ES300's?). I've heard clogged injectors and some of those issues can cause shift problems so I'm holding off until I get the sensor issue fixed.

Any direction on this A/F Sensor, where to get one, and other tips are appreciated. I hope to get this thing fixed w/out spending a fortune

VVT-i

Welcomes to CL, and get the A/F sensor from Lexus dealer. The P1133 is for AF sensor bank 1 sensor 1 mulfunction which is the right bank toward the fire wall. You have to get it from underneath with 22mm wrench or special design socket(just for the AF/O2 sensor only).
But sometimes the sensor is seized in the maniflod and that when you will have a real problem. Then in this case the exhaust manifold will have to be remove. Good luck.

Lil4cyl

I have a question! I have the sensor light and codes P1133 and P1135. Which I assumed from reading here that it was the bank 1 o2 sensor. So I called the local Toyota dealer today(Lexus dealer was closed for Jan 2) and they had the part # in stock for the o2 sensor. SO I go down there and want them to change it out... part price $218.00 and labor $104.55. They bring my car back out and tell me that the code is for the Air Fuel ratio sensor, NOT the O2 sensor! Thought they were the same? They told me there was an o2 sensor AND an air fuel sensor on the car, and that they did not have the air/fuel sensor in stock. They would have to call the Lexus dealer on the 3rd and get a price for it.

What I need to know is if there is truely a seperate o2 sensor and seperate air/fuel sensor if they are not the same thing on this car on bank 1???

This is on a 99 RX BTW. They are confusing me because I always thought the o2 and air/fuel were just 2 different ways of saying the same thing???

Lil4cyl

BTW, does anyone have a diagram from the service manual of the bank 1 exhaust manifold setup with the sensors on it? I am curious about what the dealer told me.

jqzhang

Here are a couple of questions for VVT-I for the post of 11-30-03.
You mentioned that I can use a 22mm wrench to take the A/F sensor off. Why do I need a specially designed socket? Do you mean the slotted socket that can leave the pigtail outside of the socket? I thought the wrench would be enough.
One more question. How many A/F sensors on each bank before converter? My understanding is one A/F sensor, in addition to an O2 sensor. Please correct me if I am wrong.
Thanks in advance.

Lexmex

Welcome to Club Lexus.

Some of the other members in the forum have removed the A/F sensors. From my view of it and from what I have heard, you need a good amount of torque to get these off...they're not easy to remove necessarily, even if the wrench fits on the bolt.

There are two A/F sensors, 1 on each bank. Bank 2 is on the front (viewable when you open the hood) and Bank 1 is on the back and not readily visible.

TunedRX300

I may do a photo DIY when I have free time since this is the 4th request, counting PMs I received over the last two weeks.
Bank 1 sensor 1 you can loosen A/F sensor with 22mm combination wrench, just soak the threat with Liquid Wrench for at least 30 minutes. The 2nd toughest part is to unclip the harness.

jqzhang

Thanks guys!
One more question. Can you easily identify O2 sensor from A/F sensor on RX300. I changed O2 sensor for my wife's 1991 LS400. Like exactly TunedRX300 said, it's one of the toughest 'fasteners' on the car. But with liquid wrench and a Snap-on box-end wrench. It wasn't so bad. The bad thing was not even think about using an impact wrench. The good thing was I had a mechanic mannual downloaded from the web (something like TechInfo.com but not sure; cost about $10). Somehow, TechInfo does not exist any more.
Thanks again.

TunedRX300

You can id by part number. Toyota A/F sensor is 89467-48011, Denso makes the sensor but uses a different part number for aftermarket: 2349009

They also look different.
A/F sensor

Oxygen sensor

cobravap

Also, if you want to do it yourself buying the part online is much cheaper than the dealership. I got each A/F for $162 or something around there. Removing the things were a PITA but i do suggest going to Autozone and renting O2 Sensor Sockets. They did help in the Bank 1 sensor. Bank 2 i was able to use an adjustable wrench to get at it. Be sure to have your car jacked up so u can have room to loosen Bank 1. If u need any more help just PM me or TunedRX300 (He helped me out). Oh and one more hint, remove the connector first, it gives you a little room when working with the O2 socket.

jqzhang

Thanks folks! I love the photos. They are more than clear enough for me to tell.
In fact, I have a O2 sensor socket but I couldn't put it in use when I worked on the 1991 LS400 since it wouldn't fit in. Some of my 22mm box-end wrench wouldn't fit in, let alone the socket. I guess RX300 should be easier because it's a SUV that allows more under-chassis manuvore than LS400.
I also heard RX300 had 100,000 miles warranty on the sensors but I am not sure if it's rumor or not.
Thanks again folks.

jqzhang

Hi, folks,
I had the part fixed, successfully, thanks to what you provided.
But the experience was terrible. Two hands were needed to unplug the harness: one for holding the clip open; the other for unplugging. But there was no room for 2 hands. When taking off the sensor, It made me feel the sensor were welded in the exhaust. Plenty of penetrating oil was used. I guess there was no anti-locking grease on the threads when it first installed.
Good thing was when the new sensor installed, both Check Engine and VSC lights were off. I don't know why VSC has something to do with CEL or the sensor.
Thanks again.

TunedRX300

Did you have a tougher time withe the front A/F sensor?
I tried to replace the front A/F sensor but it is much tougher than the one on the rear bank. I will make one last attempt use a 18" breaker bar and some PB Blaster today.

Redeemed68

I had all the described problems through out this post and the one thing missed but found in another thread...REMOVE AND CLEAN throttle body, and the IACV. Cleaning it fixed every thing, no more codes. Before I figured it out, it also caused failure to the VVT actuator. Lexus designed these parts to interact with all the variables to create failure. Heads up to any sensor reading, not always the sensor but the mechanical parts forward or linked to it.

carguy07

So you cleared A/F sensor codes by cleaning the IACV and throttle body?