When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Reviving this old thread which had me optimistic about an easier way to get to the bank 1 (US passenger) upstream sensor. I pulled back my carpet and found a hole with foil backed rubber tape type stuff covering it. Pulled that off but could not get to the O2 sensor, which was pretty much right in front of it. It is possible to get into the engine compartment, but not clear access to the sensor.
Pic just under glove box, carpet pulled back, US passenger side.
Hate to necro a thread but I just did this and can confirm two useful bits of info.
The AC drain access port IS present on both sides of the car and can be used to change both O2 sensors on the 4.0 cars.
The port pictured above is the blanked-out cutout for the steering rack if the car was a RHD car. The poster was looking in the wrong place. The actual AC drain hole is further back in the cabin here and there is one on each side:
