P0158 & P0159

[ranimouf]

I have these codes in my 01 QX4. Can someone tell me which O2 sensors to replace. Please be spesific and what brand of sensors to buy. If possible include part #. Thanks in Advance

[Towncivilian]

Read my thread, which incidentally has the same title.

Basically, you want to replace the driver's side post-cat O2 sensor. I used this sensor which I purchased for $53 online using discount code VISA. It is a perfect fit, and is the same brand as the original sensor. You will need a 22mm or 7/8" oxygen sensor socket and some time to replace the sensor.

[ranimouf]

Thanks for the quick replay.

[ranimouf]

Will this take care of both codes?. Is location of driver side Post cat behind the cat? Thanks again

[Towncivilian]

Yes, this will fix both codes. The sensor is the driver's side, after the catalytic converter.

[ranimouf]

Thanks, I looked at the sensor and I couldn't even trace where the wire is going to. I was thinking about buying a sensor without the harness and just connecting the wires to the existing harness. Is this possible? If it is, It's gonna be alot easier.

[Towncivilian]

It is possible, and cheaper. Results really depend on how well you make the connection, however.

The wire, which has a red sheathing I believe, has two clips next to the bellhousing and three or four in the engine bay. The connector in the engine bay is green. I found it difficult to remove these clips, and to remove the oxygen sensor I had to cut the harness in the engine bay, then I installed the new sensor and routed the wire the same way as the original; all of the clips fit perfectly. See ARKQX33V6's suggestion, it should help you in replacing the O2 sensor with a direct fit one.

[ranimouf]

Thanks for detailed info.