View Full Version : O2 Sensor

06-04-2012, 03:04 PM
On a 2009 Rav 4 3.5L I have an error code.

HO25 heater control curcuit lowbank one sensor 2.

So I need to replace Oxygen sensor number two but I don't know which one it is in respect to its location on the exhaust. There are 4 of them but they are labeled right upstream, left upstream, right downstream, left downstream.

Can you tell me which one it is so I know how to locate it next time and the part # to it.

06-04-2012, 03:15 PM
Usually bank 1 or 2 indicates the side of the motor (bank 1 refers to the side with #1 cylinder on it). I'd say it's the downstream sensor on the exhaust line on the #1 cylinder side.

My educated guess from past obdII exhaust codes.

06-04-2012, 03:56 PM

Aaron Willis
06-04-2012, 05:50 PM
That's a little out of my reach. I'm a good parts guy, but I am not a technichian, and the tech is the one who is trained to interpret codes, confirm diagnosis (i.e. do more than just read the code to verify what the car actually needs) and then tell us which part he needs. He's the doctor; I'm just the pharmacist.

I can tell you that Toyota's V6s generally mark the right bank (in a transverse engine, the one toward the firewall) as number one, and that "sensor two" generally indicates downstream. The part number for the right bank downstream sensor is 89465-0R030, but again, I really cannot guarantee that that is what the code indicates or what you actually need. I'll put the pills in the bottle but you have to ask the doctor which pills you ought to be taking.

06-04-2012, 06:13 PM
Off-topic, but I am so using that doctor/pharmacist analogy. Nice one Aaron!

Aaron Willis
06-04-2012, 06:39 PM
I'd like to take credit for that, but I borrowed it from another one of our counter guys here :shush: Pretty useful, though, when someone gives you the deer-in-the-headlights look, not understanding why a verbal description of their symptoms doesn't tell us which part they need.

06-04-2012, 09:00 PM
Unplug the one you think it might be, then check for codes. If you still have one code, the one you unplugged is likely it. If you get a second code, you guessed wrong.