How to replace O2 Sensors

Alright, i decided to make this, since i just did it on both Bank 1 and Bank 2 (upstream/downstream) sensors.

Also the "lieblweb" how-to link has no real visual reference, since the photos are blown out and tiny.

Anyway, here we go!


All work was performed on a 2000 Toyota Tacoma SR5 Automatic V6, NON-CA model.




Materials needed:

• Denso Oxygen Sensor (with gasket), Part #
  $52 234-4162 Oxygen Sensor with 4-Wire 10.5” Harness for Non-California, Non-4WD Lexus/Toyota
  234-4162
• 12MM Line Wrench
• Anti-Seize lubricant
• Wire Brush (if area is rusty)
• Vehicle Lift
• Good lighting
• Beverage of your choosing

• Note: The type of transmission, drivetrain, and Emission type will change the part number for your O2 sensor.

• Also note: OEM sensors are DENSO. Many folks have put in Bosch or "universal" only to have them fail a few thousand miles down the road.

• Also Also Note: Line wrenches are a life saver, because more than likely the nuts holding your sensor in place are fairly rusty and corroded, and a normal wrench has a higher propensity to strip them smooth.

Down to brass tax:












I figured this would give a clearer picture, of "where exactly" the 2 Oxygen sensors are.

Step 1: Unscrew the 2 nuts retaining the bad sensor.



Step 2: Unclip harness. Use a screwdriver to pry the retaining tab off of the hook





Step 3: Remove new O2 Sensor from box


Step 4: Clean the area



Step 5: Put sensor in, and apply anti-seize lube to bolts


Step 6: Tighten nuts back on, and tighten the sensor *firm* but not to hard. Its not pressurized like a spark plug, so it doesnt need to be torqued down. Just tight with a quarter turn for peace of mind


Step 7: Plug in connector


Step 8: Wipe up the area, clean your hands, and enjoy a beverage

 

Wow, this is a great website! Thanks for the info. I couldn't be better put.
My son is a Master Auto Tech but sees me as a Pain in the A--. last time my O2 sensors went out on my Ford he got them both wholesale for $100. Problem was he guessed which ones were bad and he was wrong. I was out the money.

 

Thanks for the step-by-step, Nick. I was *easily* able to the down downstream #2 sensor in about five minutes. Not so with the faulty one. The upstream #1 sensor has its electrical connection parked waaaaaaay up on top of the transmission, where the wiring is inconveniently stored. The "crux move" as we say in climbing parlance – the most difficult part of the problem – is in undoing the electrical connection parked where it cannot be seen nor easily gotten to. If I pay hundreds to a garage for the privilege, how will they eventually get at that pesky connector? How can I do it?

 

I was able to get to the upstream sensor on a 5 spd manual 4x4 by removing the center console and taking the boots off of the shifters and going through the hole. I had to remove the sensor first and then pull the wiring up to the hole. Also had to remove the bolt holding the wire connector. A real PITA.

 

Nice write up. I had to replaced an O2 Sensor previously, heat and some swearing were involved...

 

iv replaced 3 of em between 2 taco's iv owned... Never been able to unthread them. Chop them off with a chistel becase they rot off in like 4 years I have clean/rust free truck envy right now.

 

You don't need to use a line wrench on those bolts, the closed end of a standard wrench would work better. You only need to use a line wrench when you can't fit a closed end wrench or socket over a fastener because of the need for a slot for the wires or brake lines to pass through. You use a line wrench in place of an open end wrench because it makes more contact and has less chance of stripping than an open end wrench.

You normally do need to use a line wrench on most oxygen sensors though. That's because most of them look like this


The design used on tacomas is actually much better IMO, eliminates the need for a line wrench wrench or special socket which is actually a big deal in cars that have O2 sensors in hard to reach areas.

anti seize is a great idea, and putting some dielectric/silicone grease in the electrical connectors is a great idea as well to protect from corrosion.

Also, anytime you're removing ANY exhaust fastener, soak that shit with some penetrating oil and let it sit for a few minutes first. If your truck is pretty rusty, I'd soak it several times leading up to when you want to remove it. Decreases the chances of breaking/rounding fasteners and lots of swearing.

Mine actually just went bad yesterday. This was the best deal I could find on the OE denso part.

$170 Denso 234-9003 Air Fuel Ratio Sensor

http://www.amazon.com/Denso-234-9003-Oxygen-Sensor-Ratio/dp/B000C5UFU8
I would have paid more to get one at a local parts store immediately, but all of them only had the lowlier bosch sensors in stock.

 

This was the best advice. Thanks. Everything worked out great.

 

Glad it helped. I sure couldn't figure out any other way, but I am sure there is a one, lol.

 

Thank you for this! This is on my list of things to do. Anyone know where the best place to get the sensors besides Amazon?

 

Awesome write up OP. Some green love to ya!

 

Thank you very much for the suggestion. I followed your method and it worked... i didn't have to remove the bolt holding the wire, but finally the connector was disconnected after lots of cursing and struggle....

 

awesome! thanks for the step by step with photos! this should be a sticky

 

This is by far the dumbest fucking design flaw I've encountered on this truck.

If they just moved the clip, where the sensor ties into the wiring harness, back 2" this would be a five minute job.

Instead they decide to make the fucking clip impossible to reach from either under the truck or through the hole in the tranny hump.

How you were able to remove 14mm bolt holding the harness, let alone get to the clip is beyond me. I can get a socket on the bolt but there is no way to move the driver because of the stick shift and body prevent any movement.

I can barely fucking touch the goddamn clip with my fingers let alone even fathom out to unclip the sensor from it and insert the new one. It's as if you have to drop the fucking transmission to get to this fucking clip.

What a pitiful design by Toyota. Meanwhile the downstream sensor wiring clip is right there next to the sensor. Easily accessible. Imagine that.

 

Is it ok to put anti-seize on the bottom of the o2 sensor gasket? I ask this because my friend who helped me install this did this before I could say anything lol. I hope the anti-seize doesn't leak into where the o2 sensor is.

 

Looks easy to do, thanks for the writeup! Should become a sticky so we can find it easy when we need it moderators.

 

as long as its not a crap ton, you should be fine. if it freaks you out just pull it off and wipe it clean.

 

One other thing. Is the gasket reversible? Can it go on either way? Thanks.

 

I asked the parts guy at the dealers counter. He said you can put it either way. I tried to put the new one on the same way the old one came off.

 

https://www.google.com/#q=234-4162&tbs=vw:l,p_ord:p&tbm=shop