O2 sensors - Toyota Nation Forum : Toyota Car and Truck Forums

trakaill · 07-20-2009, 06:09 PM

I have a 2003 Corolla CE. I was wondering what is the best way to go about replacing the sensors. I was recommended Bosch sensors. Apparently they are the ones that will require the less work. Are the front and back sensors the same?

mikered30 · 07-20-2009, 06:25 PM

Front and rear are different and Bosch are probably the worst to use on a toyota, besides universal sensors. Stick to NGK or Denso. The best way to remove them is the self tapping method and a lot of elbow grease. Spray some pentrating oil around the threads and allow to soak. Warm up the engine a bit and use a wrench to remove them. Make 4 turns out and then 2 turns in. You do not want to strip the threads.

JasonA · 07-21-2009, 07:05 AM

I second the suggestion against Bosch sensors. I've not had luck with Bosch parts at all, unless it was specifically the original part. And even then, the Bosch part you buy at AutoZone or something often isn't the same quality as the original part.

I'd use the same parts that came on the car (same brand/model number).

Rdkill · 07-21-2009, 02:55 PM

The after cat O2 will be a pain....

trakaill · 07-22-2009, 09:58 AM

First off thanks for fast reply!
Well here is the thing.. I have 114K on the car and Id like to keep for at least another 100K so I dont want to put some low quality sensor thats gonna go bad to fast...Bosch claims theirs will last 100k...
Ive heard good stuff about Denso as well! Ive never done it before but I know a mechanic who will help me. I wanted to ask here first cause he has never worked on a corolla but mostly on german cars. (AUDI, BMW) The one after the cat needs the car to be lifted but that should not be a problem either.

I will go to Nappa and AUtoZone and see what they have to offer!

One of the local car garage here was asking me some sick amount to replace them... Ive read a little about it and its not a huge deal of work...a couple hours and knowledge should suffice.

JasonA · 07-22-2009, 10:59 AM

DENSO Part # 2344800 is for the front sensor.
DENSO Part # 2344233 is for the rear sensor.

Denso is the OE supplier, and it's absolutely what I'd use. But before I replaced anything, I'd ask why you are replacing them, especially both.

mikered30 · 07-22-2009, 11:31 AM

Do u have a code or crappy mileage or just preventative maintenance? Just a warning it will be very hard to remove the sensors due to the high heat environment. If you get the sensors from the dealer they come with antisieze on them. Advanced auto sells NGK plugs so it is likely they could order your NGK or denso sensors.

I don't think the post cat sensor requires the car to be on a lift. You will have to pull back the carpeting on the passenger's side to access the plug end. There is a service manual floating around on here for that.

holler1 · 07-22-2009, 06:28 PM

I agree, no need to use a lift. I drove the front onto ramps when I changed both O2 sensors on my daughter's car. A special socket with a cutout is very useful. For the rear sensor, the connector inside the car is a little hard to find behind the carpet up near the center console. For the front one, I took off the heat shield, but it can be removed without doing that.