How to replace Oxygen Sensor 1999

Hello,

I read in a manual at the library that for the 1999 Camry, i will need to pull out the front seat, driver side to replace the downstream Oxygen sensor!

Is this true?

If so, is this doable by your average do it yourselfer?

Or if there is another way, i'd appreciate hearing about it!

Thanks very much!
BobK Fairfax VA

It is doable. I replaced it about 15 months ago on my 98. You don't even have to pull out the driver's seat. You can just reach in and pull the carpet back by the heating duct that delivers heat to the back seat floor area. A Toyota tech showed me that. Attach a long piece of twine or mechanics wire to the electrical connector and undo it. Then pull it through from underneath the vehicle, leaving some of the twine still inside the passenger compartment. Now remove the O2 sensor from the exhaust by unscrewing it. A long O2 sensor socket works best, but you may be able to do it using an open end 22MM or 7/8 inch wrench. Some liquid wrench or PB Blaster works well here. Screw the new sensor back in, and then pull the connector back in to the cabin area using the twine you left attached to the old sensor. The new sensor (OEM) has a plug on it to seal the floor area. Plug the electrical connector back in and you are done.

Mike

It is doable. I replaced it about 15 months ago on my 98. You don't even have to pull out the driver's seat. You can just reach in and pull the carpet back by the heating duct that delivers heat to the back seat floor area. A Toyota tech showed me that. Attach a long piece of twine or mechanics wire to the electrical connector and undo it. Then pull it through from underneath the vehicle, leaving some of the twine still inside the passenger compartment. Now remove the O2 sensor from the exhaust by unscrewing it. A long O2 sensor socket works best, but you may be able to do it using an open end 22MM or 7/8 inch wrench. Some liquid wrench or PB Blaster works well here. Screw the new sensor back in, and then pull the connector back in to the cabin area using the twine you left attached to the old sensor. The new sensor (OEM) has a plug on it to seal the floor area. Plug the electrical connector back in and you are done.

Mike

Thanks alot Mike, really appreciate your very considerate help!

I'm going to scope it out next weekend and then order thru AF parts!

Have a great year Mike!

BobK Fairfax Va

That's to do the post-cat o2 sensors. It's next to unheard of for one to fail. Double-check your troubleshooting / code reading & make sure you don't need to change the actualy o2 sensors used for tuning located before the cat on the exhaust manifold<s>.

bobk,

You're welcome.

Toysrme,

He originally asked about the "downstream" O2 sensor and his description of removing the seat is only done for the downstream sensor. I did have it fail on my 98 5SFE at around 70,000 miles. Not really that hard to replace.

Happy New Year to all.

Mike

FYI -

I know that the Upstream o2 sensor for 99 camrys are different for CA vs. Non-CA models. To make matters more complicated - it was quite common for CA models to be sold outside of CA. Having a CA model in NY - I've cursed toyota several times when (on the rare occasions) I needed to purchase emission related parts.

The Non-CA models use a traditional heated O2 sensor, while the CA models used what is called a "Air-Fuel sensor". They look identical, but they are very different. Traditional O2 sensors act like a switch (flipping the output voltage between .3 and .8 volts as the air/fuel mixture changes). The Air-Fuel sensor's mode of operation is quite different. Instead of acting like a switch, it maintains the air/fuel mixture using subtle, linear voltage changes in the .3v range.

The downstream O2 sensor should be a "traditional" O2 sensor for both CA and Non-CA models - but you may want to make sure of this when purchasing the sensor.

Anthony