Exhaust Sensors ....

nyc4runnin

nyc4runnin

New member
So i've been trying to battle the check engine light for the past 3 years on my 99 SR5 Highlander 3.4L V6. Since I live in NY, we need to get emissions checked every year. I've been going to autozone to borrow the scan tool to clear the light before I get the emissions checked so it passes.

On the scan tool, it says that the (Oxygen/ A/F ?) sensors are bad on the exhaust. Anyone know where these are located and what part numbers these are ? I've already replaced the one next to the air filter on the intake side 6 months ago and that cleared the light for a good 30 days. but now these codes always come back after a week or so of clearing them.

Thanks!
 
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These are typically called "O2 sensors" and are located in the exhaust system. They are screwed into welded threaded inserts in the exhaust pipe. They are located at intervals through the exhaust system (after the manifold, after the cat, after the exhaust). They aren't cheap, so it's best to do a bit of legwork and figure out which one is bad. They are simple to replace.

Here's a Bosch sensor for your vehicle from O'reilly:
http://www.oreillyauto.com/site/c/d...icle=true&partType=02205&parentPartType=C0018

This is a write-up on how to replace the sensor:
http://www.4x4wire.com/toyota/4Runner/tech/O2_Sensor/

BTW, just so you know, if you live in a county that tests for smog emissions, they wont pass your vehicle if you've cleared the computer in the past few weeks. At least that's how it works down here...
 
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wow thanks ! just the info i was looking for. Any difference between the bosch and the OEM Toyota sensor ? its $111 for the OEM one on partznet and $12X for the bosch one ....
 
I would stick with an OEM Toyota sensor if your budget allows...think about it...you've got easily 100,000+ miles out of that sensor...there is NO aftermarket sensor that will last that long. I promise.

BTW, where in NY are you? I'm out on Long Island!
 
wow thanks guys !

im actually in CT right now with my 4th gen, I keep my 3rd gen in queens near the cross island pkwy.
 
Stick to Denso, if you do your research you will see much unhappiness deriving from the wrong sensors. These puppies are very sensitive. A good source:

Link to URD

At least use their list to get the RIGHT Denso part number for your rig. You can then find that Denso sensor elsewhere for a few $ less, example Amazon. However, Amazon's application info is sketchy, so check URD first. Please post the DTC number and we can help you figure out which one is bad. For example, p0420 is usually rear, if it's not a bad cat (really big $$$$). P1135 is your front. Also tell us if you have a one-cat (49-state) or two-cat (Cali.) set-up. Lot's of Cali. '99 were sold in the East, including mine. The sensors are VERY different in front.
 
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TheDurk said:
Stick to Denso, if you do your research you will see much unhappiness deriving from the wrong sensors. These puppies are very sensitive. A good source:

Link to URD

At least use their list to get the RIGHT Denso part number for your rig. You can then find that Denso sensor elsewhere for a few $ less, example Amazon. However, Amazon's application info is sketchy, so check URD first. Please post the DTC number and we can help you figure out which one is bad. For example, p0420 is usually rear, if it's not a bad cat (really big $$$$). P1135 is your front. Also tell us if you have a one-cat (49-state) or two-cat (Cali.) set-up. Lot's of Cali. '99 were sold in the East, including mine. The sensors are VERY different in front.
Click to expand...

anyway to tell cali from federal from the vin ?
 
I actually have a 2nd gen (1990, one O2 sensor) so I'm not even listed in URD. The NGK is $35 less than Denso. Would I be taking a chance with the NGK not working correctly?
 
Okay so i took it to autozone and used their scan tool to pull the following codes ...

P0125
P1135
P0420

from what ive been reading, these are toyota specific codes. the description given by the scan tool is bullshit because it talks about throttle position sensor, coolant temp, etc .... which i never had a problem with.

http://www.yotatech.com/~corey/tech/dr_z_obd/dr_z.htm

code description on there points to bad o2 sensors, i guess their time is up cause i have almost 140,000 miles on the truck and ive only changed tires, water pump, timing belt, and air intake sensor over the last 3 months lol

i'll be ordering 2 of those bosch sensors from amazon.com because they are half the price of the dealer ones(too poor this time of year for oem parts:sobbing:)

hopefully it fixes these codes, otherwise i think the next step would be a bad cat ....

fyi... this guy had the same codes on his 4runner from mass. theres a post in there that explains how to check if the sensor is bad using a multimeter... i may try this first if i have some time.
http://www.obdii.com/ubb/Forum1/HTML/002422.html

thanks guys !
 
In case anyone else needs these part numbers ...

This is for a 1999 4Runner 3.4L V6 Cali Spec Automatic Tranny ...

Toyota Part numbers for front A/F Sensor and rear O2 sensor

89467-35011
89465-49105

Denso Part numbers for front and rear (should be the exact same part as the factory toyota)

234-9002
234-4153

Bosch Part numbers for front and rear

13613
13136


FYI ... Amazon.com had the lowest prices I found for the denso and bosch sensors.
 
Just changed my Sensor 1 Bank 1 O2 sensor (or Some sort of Air sensor as it's named for CA emissions vehicles). Seems this is the common one to go out on the toyota's. My Sienna's went bad a year or so ago but there was no way I could do that one my self without a lift and several extensions and swivels. The 4Runner one is easy. First sensor on the manifold coming from the engine on the passenger side. Not sure about that P0420 code but the other two I had on both the Sienna and 4Runner. Good luck with it! You'll be happy with the improved gas mileage when you get it working!
 
alchik said:
Just changed my Sensor 1 Bank 1 O2 sensor (or Some sort of Air sensor as it's named for CA emissions vehicles). Seems this is the common one to go out on the toyota's. My Sienna's went bad a year or so ago but there was no way I could do that one my self without a lift and several extensions and swivels. The 4Runner one is easy. First sensor on the manifold coming from the engine on the passenger side. Not sure about that P0420 code but the other two I had on both the Sienna and 4Runner. Good luck with it! You'll be happy with the improved gas mileage when you get it working!
Click to expand...

did you go with a dealer/denso part or aftermarket(bosch) part ?
 
Update: I replaced both sensors now with bosch ones and cleared the codes. About a day later the CEL came back and went away for about another day. Now its on for good. I havent had a chance to check the codes. But im thinking its either a bad cat or a small leak. I noticed the flange for the O2 sensor was missing alot of metal due to rust. The 2 nuts for that sensor were completely gone, only rust was holding the sensor in place the whole time !

Anyone have a cheap source for the OEM cat ? or any aftermarket suggestions for an entire exhaust ?
 
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