2003 - how to get to upstream passenger o2 sensor? 4.0L engine

i tried it from every angle....can't get to it from top of bottom...no room to maneuver a wrench

upstream passenger (bank 1?) is the one I am trying to replace

maybe there's a different tool to get?

 

Did you search at all? There’s a post about this a few tabs down.

https://www.4runners.com/threads/changing-upstream-o2-sensors.47054/

 

I still dont know what exact tool size/type to use on passenger even after reading that....or from top or from bottom? do i need to take anything out besides intake to get at it?

 

Does no one use youtube University first anymore?

Can't imagine what some people would do without the internet.

https://www.youtube.com/watch?v=z1FVJsCdF4s

 

It’s not as simple as that video. Trust me, I’ve been on a real TLDR journey with the same Bank 1 sensor and it’s a tough cookie.

@anarky321 - Hose it with penetrant, soak, then try this sensor wrench loaner from Autozone. It worked better than the sockets for me. I was able to get it on the sensor from underneath with enough space for the handle forward of the sensor to get two hands on it. The good news is that once you break it loose, you can turn it by hand the rest of the way. Same thing with installing, hand snug then tighten down with the wrench. Torque is 33 ft lbs but that’s meaningless when you can’t even get a regular wrench on it. Just crank it down as best you can. Doesn’t need to be Hulk-tight.



Be careful on the install because my new ones came with antiseize on the threads and it’s easy to accidentally smear it on the sensor when blindly trying to thread it in.

In case it’s helpful, I created this custom dashboard in OBD Fusion. I have their optional Toyota add-on, but I think you can get most if not all of these parameters without it. This helps because If something’s up with the sensor, you don’t have to just wait for the check engine light to come on. You can see whether both banks are in the ballpark with each other and whether the fuel status mainly stays at 2 with occasional short changes to 4. That’s a long explanation so you can find more online if you want. The bank values won’t be identical and will constantly change, but they’ll be close.

 

Reminds me I have two more ‘spaces’ available on my main ultragauge page. I should add B1S1 and B2S1 voltages.

 

@anarky321 - One more tip. The plug is another PITA b/c you have to hold the release tab down on the female (harness) side and pull the sensor plug (male) with the other, which I found impossible with only one hand. I ended up using a rubber tie-down with a hook on the end (a bungee would probably work too). I hooked it on the wire bunch going to the sensor plug and brought it out to where I could grab it with my right hand as close to the plug as possible. Then I reached in and pressed the release tab with the other hand and gently began pulling on the tie-down (you don't want to damage the wires). It eventually popped out.