P0161 code

It seems it's my turn to replace an O2 sensor. I've never had to replace one before. It's saying bank 2 sensor 2 which appears to be the easier one to reach on the passenger side.

• Was it Heather that determined it's cheaper to just order a Denso replacement instead of going through Toyota?
• Do they come with a new gasket?
• Aside from a thread chaser, what other tools are recommended? O2 sensor socket?

 

I never used a thread chaser. Usually, if the nut was stuck it would take the stud with it. I just purchased the replacement studs on 2 of the 4 nuts I removed. The 2nd time round, the nuts just snapped off they were so corroded.

 

I will warn you the dealer couldn't find a part number for the stud so I just brought it the old so he could match it. Wasnt perfectly the same, but it worked.

I don't know about the gasket and whether it came with it or not. Got my Denso sensors from Rockauto.

 

Yeah I just did all mine yesterday. Needle nose vise grips were the only way to get the rusted nuts off. Get new nuts and washers. Doing the studs too seems like a pain so hopefully you don't need to. New sensors from RA come with gaskets. I used new stainless washers and nuts on my downstream.

 

@NickB_01TRD did you order the hardware from Toyota? I've been trying to track down the part number. Can you confirm it's 9017908059?

 

I got all parts from rockauto. Nuts were from home depot. M8 nuts. I believe its M8x1.25.
2344162 is rockauto part number
For what its worth the downstream sensors only monitor catalytic efficiency and don't actually effect how the truck runs from what I've heard. My truck had 3 o2 sensors with bad heater circuits and it ran fine, probably just poor fuel economy.

 

Are you gonna replace just the one or all 4 since you’ll be there?

 

I'm ordering all 4 sensors. I know the previous owner had 1 replaced at Toyota years ago but I think the rest are original.

 

This has been crossing my mind lately just for preventative maintenance. Pretty positive all are original with 215k on them.

 

I rented this from oreilly. Fit both upstream sensors.

2344169 is denso upstream sensor on RA

 

That and a 1/2 in drive 18-20" flex socket wrench worked for me. Sprayed it over several days and then did a small movement to loosen, then tighten. Went back and forth till it came loose.

 

As I now recall I used the double nut approach to loosen the nuts.

 

My upstream came loose with the socket and just a regular 1/2 inch ratchet then I just loosened by hand. Never sprayed anything on them. Might have just got lucky.

Double nut approach?

 

I found and old post and this is what PHM used. Thoughts?

$13 ARES 70039-3/8" Drive by 7/8" (22mm) Offset Oxygen Sensor Socket - Wire Gate Accesses Sensor from Side, Preventing Damage to Wires

https://www.amazon.com/gp/product/B01C4OB3XC?smid=A1S731XAYKTTWV

 

Sorry, I meant to say the stud.

Thats when you stack nuts to remove the stud by holding the one above with a wrench and try to loosen the one underneath.

Its been awhile since I did it.

 

Yeah, that would work as well.

 

That's what comes in the o'Reilly kit and that's what I used but it's free this way as long as you take it back anyway

 

Get a heavy pair of gloves and take them out about 10 minutes after driving. The front should come off pretty easy that way.

The nuts on my rear ones like others said just rotted away so I just had to get new nuts.

 

Did everyone have to cut those nuts off or what? I really need to buy a cutting tool of some kind.

 

Sometimes they'll just completely rust themselves into nothing. One of mine did.
Might just get under there and take a look at what ya got. The needle nose vise grips got mine right off

 

Mine literally fell apart and the sensors blew out.

 

My Tacoma did that too. Funny enough after replacing the nuts my check engine light for p0420 went off.

 

A nut splitter or a dremel will do it.

 

Second reco for nut splitter if you don't have one. But I don't know if you'll need one.

After your next couple drives, hit them with cold PB after your drive when they're warm. 2-3x should do as much as you need.

Don't sweat it though. O2 sensors only get a bad rap because of folks who live in the rust belt and can't stop degradation, and not having the right tools.

It honestly is worth it to get the proper open-end socket to use.

 

Soaking my nuts this morning. They don't look too bad. I'll do it again after driving a few times.

Boy those front ones look real fun to reach.

 

Wow. Those look like they'll come off easily. I forgot how much less corrosion you have than up here.

Hell, even my new nuts look more corroded and they're less than 2 years old.

 

You''ll definitely want that socket you showed earlier. Bought my sensors from our local yokal Napa and he had an oxygen sensor socket kit he let me use....life saver. Also, unplugging the connector was my biggest challenge on the 2 fronts with what little room you have to maneuver your hands. Also didn't help that I did it on a cold ass day making it difficult to feel in tight quarters. Patience helps also !

side note....if you have a volt/ohm meter, you could verify for kicks and grins the resistance of the 2 conductors for the O2 sensor heater circuit for an open or short condition !

 

I don't know much about 02 sensors. What would that tell me?

 

Since their not cheap, it would confirm if the sensor heater circuit itself is indeed bad or a wiring issue !