After cleaning my Mass Air Flow sensor and resetting the Check Engine light, I still get the same P0171 code. So, most indications point to the O2 sensor as my 4Runner as 66,000 miles. So, I am checking the location of the front O2 sensor in front of the catalytic converter and the plug for the sensor is mounted to bracket way up on the top side of the transmission case. Impossible to get to without dropping the transmission down. Has anyone run into this situation and what solutions do you have to get to the plug to do an R&R of the O2 sensor? One thing that came to mind was to cut the wires and electrically splice in the new O2 sensor, but that seems a bit radical. Thanks for any help. Steve

 

You can get at it from inside the truck. I just replaced mine on my 5spd last weekend. You have to take the center console apart around the gear shift levers. After getting to that part you can just barely reach the connector. I took some photographs of the project and will try to post them tomorrow.

-Sherpa

 

The connector is a locking type, where one half has a little lever on it to release the other half. And yes, it can be separated from under the truck, just takes a bit of patience and knowing what your feeling for.

That being said, its probably not your O2 sensor. Its still most likely the MAF, and wasn't cleaned properly.

See posts 10 and 11

 

Thanks for the replies, I will try to get to the plug from inside the truck. I tried my damnedest from under the truck ... I can only barely touch the plug with the finder exteded and my arm jammed into tight spaces.