2008 (how many o2 sensors and AFM sensors)

So just how many total o2 sensors and AFM sensors does a 2008 4 -Runner have? I’m getting error codes.

 

4 total. 2 AFM are upstream of the cats, 2 O2 sensors are downstream. Theyre on each respective side of the exhaust tubes coming down from the manifold.

Amazon and RockAuto are my go to for replacements, and yes Amazon does have OEM Denso parts long as you correlate the part number. What codes do you show? Any recent mods that mightve caused the error?

 

Thank you for responding to my post. I don’t recall the two error codes as I cleared them out with an OBD reader. Originally, I did replace the fuel cap, but the VSC and check engine light came back on. That is when I had purchased the OBD reader and then cleared the codes. I’m sure those warning indicators will come back on, but just wanted to know how many sensors I need to replace. I plan to replace all of them regardless. So far the warning indicators have not returned.

 

I mean the VSC/CEL/et al lights that pop on can come from a ton of different issues... those codes will be the tell tale indicator unless you can find the issue with the naked eye. Those sensors can get to like $40 per. Thatd be a bummer to replace any or all of them for it not to be the culprit

 

I believe one code was P240 and mentions bank 1. I don’t recall the other.

 

So I'm inclined to think youre misremembering the order there and its instead a P0420 code. I cant find that a P0240 code exists for the exhaust system. If you do buy new sensors Bank 1 should be passenger side (looking at the engine start left to right) though someone may well say different. Supposedly it depends where youre buying from - Toyota says looking at the engine block 1 is left 2 is right; but RockAuto references them as if youre in the driver seat, so "left" refers to the drivers side and "right" to passenger.
Info: https://parts.olathetoyota.com/p0420-code-toyota and https://www.fixdapp.com/blog/p0420-toyota and https://www.4runners.com/threads/p0420-which-cat-is-bad.17639/

 

Yes, that was the code it pulled. So far, the warning lights have not returned after I cleared them.