Lexus IS Forum banner

o2 Sensors and CEL Code Diagram

58K views 45 replies 26 participants last post by  C1ph3r  
#1 · (Edited)
Let me start off by saying that without all the various information, tips and how to's on this forum, I would still have a set of megan racing + y pipe sitting in my room doing nothing! Thank you to everyone that posted their experiences and tips!

I found that all the information you need when installing something CAN be found on the forum, it just takes a bit of searching and a lot of reading. The more posts and threads made every day, the harder it is to find these goldmine threads so I thought I would contribute a little to the forum to help new users understand o2 sensor related CEL errors.

I'm not very good at explaining things so I thought a picture would be best ;)
All the information below has been obtained from various posts. If you find any errors, pm me and I will update it!

Image


Search keywords: CEL o2 oxygen sensor headers ypipe y pipe errors odb P0030 P0031 P0032 P0036 P0037 P0038 P0040 P0041 P0050 P0051P0052 P0053 P0054 P0056 P0057 P0058 P0059 P0060 P0130 P0131 P0132 P0133 P0134 P0135 P0136 P0137 P0138 P0139 P0140 P0141 P0150 P0151 P0152 P0153 P0154 P0155 P0156 P0157 P0158 P0159 P0160 P0161
 
#2 ·
This right here solved my problem so easily...I ended up plugging the bank 1 post cat O2 sensor into the bank 2 pre cat spot (for my Mazzuri) and got a p0154 Thanks a lot man. +rep for the diagram.
 
#7 · (Edited)
Here's some more info...
DENSO sensors - same as OEM (they make the OEM sensors), but much less cost.
I ordered mine through Denso automotive parts available online at DensoProducts.com and it showed up with TOYOTA and the OEM part No. stamped right on it! This is the exact same as the fectory sensor with the electrical connector and the floor grommet (for B2S2).

Applications:
B1S1 #234-4626 2001 to 2005
B2S1 #234-4630 2001 to 2005
B1S2 #234-4015 2001 to 2005
B2S2 #234-4517 2001 to 2005

The actual DENSO site DENSO Aftermarket: Denso Aftermarket Quality Car Parts has better info and pictures of the sensors.

I paid $114 for B2S2 #234-4517 .

More codes for the second sensors:
P0420: catalyst system efficiency below threshold (bank1).
P0430: catalyst system efficiency below threshold (bank2).
 

Attachments

#10 ·
Excellent diagram!, I was searching all over the place without knowing how much information is in this forum. Your diagram helped me realize I bought the wrong sensor, good thing I bought it locally. This saved me money and time, Thank you!!!.

The only thing this diagram doesn't represent too clear is the exact location of the sensors (is hard to tell where the wires end for the bank 1 sensors). I had to go back to another document staging:
* Bank 1 refers to bank that includes cylinder No. 1
* Bank 2 refers to bank that does not include cylinder No. 1
* Sensor 1 refers to the closer sensor to the engine body
* Sensor 2 refers to the farther sensor away from the engine body

This is an extract of a repair manual for 2002 Lexus IS300 (RM869U) so it's reliable information.
 
#13 ·
+rep for the diagram! during the install of my mazzuri i got these all mixed up. One question I do have tho... The threads are really bad on my b2s1 to the point where i'm scared to try to take it out. Can I simply cut the wires that are going to b2s1 and b1s1 and swap them? Basically are b2s1 and b1s1 the same O2 sensor, but with different connectors?
 
#16 ·
Is the diagram incorrect? Should B2S2 be pointing to the cat on the header? Right now it is pointing to the o2 on the y pipe.
 
#30 ·
Well I’m going to be that guy that opens up an old thread for a little help and to keep from starting a new thread.
A little back story. Just bought the car yesterday. 01 IS300. The PO just replaced the mid pipe because it had a clogged cat. He said he also replaced an 02 sensor. I personally had no idea the car has 3 O2 sensors? Is that right. On the way home with the car I threw a CEL. After scanning it I’m getting P0420. Anyway from looking at the diagram in post 7 it looks as though some wires are switched around? Is that correct? Or did he put the wrong O2 sensors in?

Thanks in advance for any help,
A.W.
 
#31 ·
The car has 4 02 sensors. I believe the one the PO replaced would have been the very last one, which normally would throw code P0430. I think the code you have is an upstream sensor, so you could try replacing that. But if the cat under the car was clogged and needed replacing, the entire headers (with their two cats) might also.