[rkv3434]

Last weekend I replaced my valve cover gasket and after re-assembly my SES light came on. I got error codes P2C40 and P2C9D relating to the bank 2 pre cat sensor. I tried resetting the error codes but they come back every time I started the car. Then I checked the lambda AFR for bank 1 and 2 using my Cobb AP. Bank 1 was fluctuating between 14 and 15 while bank 2 was stuck at 29.4.

I tried reflashing the tune but that didn't do anything. Checked the connections and everything was seated properly. Would it be ok to swap the bank 1 and 2 sensor connections on top of the fuel rail to see if the problem follows the sensor?

[Efthreeoh]

Originally Posted by rkv3434

Last weekend I replaced my valve cover gasket and after re-assembly my SES light came on. I got error codes P2C40 and P2C9D relating to the bank 2 pre cat sensor. I tried resetting the error codes but they come back every time I started the car. Then I checked the lambda AFR for bank 1 and 2 using my Cobb AP. Bank 1 was fluctuating between 14 and 15 while bank 2 was stuck at 29.4.

I tried reflashing the tune but that didn't do anything. Checked the connections and everything was seated properly. Would it be ok to swap the bank 1 and 2 sensor connections on top of the fuel rail to see if the problem follows the sensor?

I don't think it is a good idea. The engine is broken down into two banks of cylinders and the emission system checks the operation of the cat in each pipe by evaluating the data from the up-stream and down-stream O2 sensors on the same bank of cylinders. Switching one sensor to be on the other bank while not physically moving it would not allow the OBDII system to properly monitor the cats and you'd probably get more error codes. generally, when the OBDII system says a O2 sensor is bad, it's bad and needs replacement.

[rkv3434]

Thanks for the reply, but I got bored after work before your suggestion and went ahead and swapped the connections on top of fuel rail for bank 1 and 2 pre cat sensors. Started the car and checked the AFR using the Cobb AP. The problem followed the faulty sensor. So bank 2 sensor 1 is definitely bad.

Just ordered the bosch 17098 replacement since it's much cheaper than the 17102 that is used for bank 2. It looks like the only difference is that the 17098 is 200mm longer than the one I need to replace.

[e92Driven]

Originally Posted by rkv3434

Thanks for the reply, but I got bored after work before your suggestion and went ahead and swapped the connections on top of fuel rail for bank 1 and 2 pre cat sensors. Started the car and checked the AFR using the Cobb AP. The problem followed the faulty sensor. So bank 2 sensor 1 is definitely bad.

Just ordered the bosch 17098 replacement since it's much cheaper than the 17102 that is used for bank 2. It looks like the only difference is that the 17098 is 200mm longer than the one I need to replace.

I know this is an old thread, but I am having similar issues with Pre-cat o2 sensor for bank 2 (cyl 4-6) and I'm getting ready to order parts to tackle the replacement...

Was just wondering if you had any issues using the longer Lambda Sensor for Bank 1 when you replaced your Bank 2 sensor? For some reason it's much cheaper, but otherwise appears to be the exact same sensor aside from the color of the wire jacket and the length.

Also, did you do the swap yourself? I'm debating whether to pay a shop to do it, as it seems like a real pain to reach if you don't have a lift.

Thanks for any help you can provide!

[rkv3434]

Well actually I didn't end up replacing the sensor. After trying to remove the old sensor, I realized that I had pinched it under the back left corner of the valve cover when I was replacing the valve cover gasket. So instead of trying to figure out how to remove the old one, I ended up cutting and soldering the 4 or 5 pinched wires back together. Works just like new.

Still have the replacement sensor sitting in the box just in case it ever craps out on me.

And I agree it was going to be real hard to get the old one removed especially if you don't have super small hands.