When I was installing my HFCs, I managed to throw a CEL, related to the Bank 1 Sensor 1 oxygen sensor. Luckily I found a used one from a 2011 IPL on Ebay for about $45 shipped. Before tackling the sensor on this car, I looked for a related DIY thread, but all I found was a thread asking how to change the upper sensor. Because the spaces are kind of tight, it really wasn't worth taking photos. If you have any experience working on cars, this shouldn't take you more than 35 minutes or so.

Tools required: 10mm socket, 11mm socket (Gen 3. intake), 8mm socket (Gen 3. intake) flat head screwdriver, 1/2" drive ratchet, crowfoot 1/2" drive oxygen sensor wrench, 3/8" x 36" pipe (for a little leverage), WD-40

PIC OF OXYGEN SENSOR WRENCH:


1) Remove the 5 bolts which hold on the engine cover.

2) Disconnect the negative battery terminal.

3) Remove the intake tube of the side you're working on. Since I have a Stillen Gen. 3 intake, this didn't take any time at all.

4) Look through the opening at the exhaust manifold. You can see the upper oxygen sensor. Spray some WD-40 on the sensor. Follow the wire up about 5-6 inches, and you should see the connector. In my case it was brown. Unplug the connector. You can press gently on the tab using a flat head screwdriver, if you need to. Remove the wire from the clip, located behind the wire connector.

5) Once you've unplugged the sensor, slide the crowfoot wrench over the sensor. This is where you can use the pipe for leverage. Slide it over the ratchet handle, and unscrew the sensor. It didn't take much force to break the sensor loose. Use should be able to unscrew it by hand now. If your sensor is binding up, spray more WD-40, and screw it back in, before attempting to unscrew it again.

6) Apply a small bead of anti-seize compound to the sensor threads, and install it where you removed the old sensor from. Hand tighten the sensor, making sure you don't tangle the wires as you're doing so. Use the crowfoot wrench to torque the sensor. DON'T OVER DO IT! Replace the wire into the clip.

7) Put your intake, and engine cover back on. Reconnect the battery.

8) Enjoy a cold beverage.

 

Sounds pretty straightforward. Thanks for the DIY!

 

No problem . It's really a lot easier than I thought it would be myself.

 

Which one is bank 1 sensor 1 ?

 

Drivers side: bank 2
Passengers side: bank 1

Pre-cat: sensor 1
Post-cat: sensor 2

 

thank you sir! I will be tackling this one soon

 

Quick question - are the bank numbers and locations the same on the G35?

Helping a friend with his O2 sensor issue tomorrow, on a G35x

 

I just noticed this post. FYI 1, 3, 5 are located on the left bank (passenger side) 2, 4, and 6 are located on the (drivers side)

 

Is it more common for the upper sensor to fail than the lower? Also, do you typically replace both uppers or lowers when one fails.

 

I'm waiting for the part to arrive sometime this week. I cleaned the TB's and tomorrow I'm changing out the plugs. It seems that the 2, 4, 6 (driver side) O2 sensor is much more difficult to replace.

 

Awesome DIY. My OEM cat managed to go bad somehow, so I replaced with my buddies OEM cat that he had laying around, after he upgraded to test pipes. After the install, CEL came on, "Bank 2 - Sensor 1". How is it possible that the pre-cat (upper sensor) was damaged when the manifold wasn't touched to begin with? I know his cat works fine because he had 0 issues prior to test pipes...

 

The O2 sensors are very delicate. All I can assume is that is was jarred around and damaged at some point.

 

just so I'm clear on the terms:

sensor 1 = upstream= Front = upper = pre-cat (more expensive one)

so

sensor 2 = downstream = back = lower = post cat (less expensive)

 

That is correct, though I picked up one on eBay from a low mileage wrecked G for about $50. No issues since!

 

if you need new sensors for cheap check out rockauto.. they are the cheapest I have found for new ones