I purchased two downstream sensors from rockauto

234-4521 for the right which is RWD

But the left one I just realised it says AWD and part number is 234-4518 but rock auto have no denso for downstream left for RWD. Am I missing something? Why is there not senso Left for RWD. I'm now stuck with the AWD one for the left, wondering if it will work? What's the difference?

Just compared it and the wire for the left one is extremely long compared to the original. It almost seems like the right one I was supposed to get two of as for rwd the right on works for both I think. I'm now stuck with this and need to try and just tie up the excess cable under the car somewhere

 

234-4521 is the correct downstream sensor for both RH and LH on the RWD.

Jeff

 

this looks real confusing on the number of P/N listed for the same sensor...maybe the longer harness?
But for $60 for a Denso OEM replacement vs. $200+ at dealer, can't beat that.

Its on Amazon with prime for the same price as Rock Auto: https://amzn.to/34s0rYY

 

Here are the factory part number for the oxygen sensors on the 2IS sedan:

IS250 RWD
Upstream RH (B1S1): 89467-30010 (06-08 up to 02/08), 89467-30040 (08 from 02/08 on-10), 89467-53040 (11-12), 89467-22050 (13)
Upstream LH (B2S1): 89467-30010 (06-08 up to 02/08), 89467-30030 (08 from 02/08 on-10), 89467-53030 (11-12), 89467-22030 (13)
Downstream (B1S2, B2S2): 89465-30730 (Qty: 2)

IS250 AWD
Upstream RH (B1S1): 89467-30020 (06-08 up to 03/08), 89467-30040 (08 from 03/08 on-10), 89467-53040 (11-12), 89467-22050 (13)
Upstream LH (B2S1): 89467-30010 (06-08 up to 02/08), 89467-30030 (08 from 03/08 on-12), 89467-22040 (13)
Downstream RH (B1S2): 89465-30730
Downstream LH (B2S2): 89465-53230

IS350 RWD
Upstream RH (B1S1): 89467-30010 (06-08 up to 02/08), 89467-30040 (08 from 02/08 on-10), 89467-22050 (13)
Upstream LH (B2S1): 89467-30010 (06-08 up to 02/08), 89467-30030 (08 from 02/08 on-10), 89467-22030 (13)
Downstream (B1S2, B2S2): 89465-30730 (Qty: 2)

IS350 AWD
Upstream RH (B1S1): 89467-30040 (11-12), 89467-22050 (13)
Upstream LH (B2S1): 89467-30030 (11-12), 89467-22040 (13)
Downstream RH (B1S2): 89465-30730
Downstream LH (B2S2): 89465-53230

Toyota to Denso Aftermarket Cross-Reference
89467-30010: 234-9051
89467-30020: 234-9058
89467-30030, 89467-53030: 234-9068
89467-30040: 234-9048
89467-53040: 234-9067
89467-22030: 234-9144
89467-22040, 89467-22050: 234-9129
89465-30730: 234-4521
89465-53230: 234-4518

Jeff

 

How many times will you have to do this? Search button works future members!

 

From memory, it's the first time I've done it, but maybe others have before.

Jeff

 

Jeff probably has a list of all the common replies for the same questions being asked about these cars for the past 14 years.