Two Codes: Catalyst System Efficiency Below Threshold (Bank 1) & O2 Oxygen Senso

[sixty4]

I got the following two codes on my 2000 I30:

CODE #1: Catalyst System Efficiency Below Threshold (Bank 1)CODE #2: O2 Oxygen Sensor Circuit High Voltage (Bank1, Sensor2)

For CODE #1 I found the following posts: zerothread?id=332885http://forums.nicoc ... ?id=351345

The last one mentions the following potential problems:-Replace the O2 sensor behind the Catalytic converter-Pre catalytic converter Needs to be replaced-Front tube assembly

For CODE #2 I wasn't able to find anything? Any idea what this is?

Now here are my questions:1. Any idea what my CODE #2 is?2. Any idea where I can start for the suggestions I found for CODE #1?3. I also found this tutorial, its about installing an 02 sensor in a 95-99 Maxima/I30, will this work for a 2000, and is this even likely the problem?zerothread?id=185176

Thanks

[maxhopper]

1. zerothread?id=1265372. Take care of the O2 sensor first, and see if the code comes back. If it does, you'll need to replace or eliminate the warm up cat.3. Same concept, different location.

[sixty4]

Thanks Max, I am not certain which sensor is -Bank 1, Sensor 2- in the diagram either? I can cleary see where Bank 1 is vs. Bank 2? Is it the one marked:

H02S2-B1Rear 02sensor B1

or

H02S1-B1Front 02sensor B1(Black)

Someone asked a similar question at the end of the post @ zerothread?id=120838 it was not answered, can you answer that for me?

And thanks again for the diagram link, can I jack this car up driveway style and do without a lift?


Modified by sixty4 at 7:36 AM 5/27/2009

[maxhopper]

H02S2-B1Rear 02sensor B1 - is the one you want.

Definitely doable in the driveway on jack stands.

[sixty4]

Thanks for the quick response again, I may try this weekend!

[sixty4]

Ok well I could not get my hand into

H02S2-B1Rear 02sensor B1

to get to the sensor so I took it to my local mechanic who tested it. He comes back to me and says that in his XXX test the sensor provided normal results when testing it as well as the other 02 sensors. (Not sure of the test). He said that it may be an intermittent issue that simply wont show up and did not suggest it but that I would likely have ti look into doing the CAT and the 02 sensors. Any ideas?

[4all2c]

I recently installed Cattman headers on my 05 Maxima because my Pre-cats were shot. Prior to taking out the O.E.M Precats. I would constantly receiving Bank 1 & Bank 2 codes. When I both new o2 sensors which are not cheap. They went pretty quick because my precats where shot and it jammed up my EGR valve etc... When dealing with any of the banks, take care of the situation as soon as you can. I let mine go for awhile until stall outs, bad gas mileages, smelly exhaust, poor acceleration, extreme engine heat, jammed egr, bad Pcv valve, etc.... When I installed the headers my ride felt like a brand new vehicle again because it could breath and perform again.

Check out this link below:http://www.6thgenmaxima.org/fo...=8607h ... fo...=8530


Modified by 4all2c at 8:53 AM 6/5/2009

[Amosnorider]

I Just got code p0420 on my 2000 I30. A few weeks ago i got a code for my bank one, sensor 2. p0138,p0139. Replaced that and SES light stayed off for 1500 mi. Couple days ago i got code 420 for catalyst efficiency. I had advanced auto erase my code and the ses light stayed off for ~ 70 mi. You guys had any luck fixing the catalyst code? BTW I have one new O2 sensor, and three old ones.

Thanks guys.Mo

[maxhopper]

If you continue to get the cat codes it's time to decide between replacing the factory pre cats or eliminating them if plausible under your local emissions standards, with either a y-pipe(4th gen) or headers(5th gen+).