code p0420 .. seeking resolution asap!!

[mitch01]

I own a max 01 . the dealer diagnostics said i have to change the front assembly tube ... Should i just install a y pipe and eliminate the pre cats . If anyone ever had this problem pls send any info as to how and wat they did to resolve this thk u in advance ... peace out

[MinisterofDOOM]

P0420 is "Catalyst System Efficiency Below Threshold (Bank 1)"So you either have a bad oxygen sensor or one of your rear bank cats is bad.

[paluli]

i had the same problem, i replace the bank 1 sensor 1. i bough my at oxigensensors.com part #250-23133 made by walkers. and the ses. has not coming on has been about 80 miles. since them

[mitch01]

really appreciate the info .. but was your i30 a fed or a cal emissions? and secondly , is that sensor the one close to the firewall on the i30 thaks a whole lot for the info

[paluli]

Yes my i30 is cal imssion. and yes is the one close to the fire wall, the oxigensesors.com has the part wrong, but tell them you want the oxigen sensor part # 250-23133. thats if your maxima is cal. imssion. if not they will help you.

[mitch01]

while changing the sensor i broke off the bung that the sensor screws in too....so now i have a hole in the manifold .... just my luck . so i ended up at my mec. We pulled the entire assembly off ...chopped off a bung from had on an old cat.he had lying around ... mig welded it on to my manifold .screwed on the new sensor ... reassembled and started ........ SES gooooooooooone .SWEET ...... It took about hour . and alot of swearing on behalf of my mec. But dude i must say thanks , really appreciate the info . thumbs up