Engine code question

[tbsbiker2]

I'm getting the P0140 code (I have a scanner)...and I know it's the Bank 1 Sensor 2...but I've been resetting the code (over the last several months)...and it doesn't show up for weeks or even a month or more then if I get on the engine hard or long hwy stint it will usuall pop. Is this probably bad / sensor related or could it be some other condition making it happen? I guess I have no other options than replace the sensor first? I don't know how to test them. Car runs like a champ though.

peter
2001 SE 4 x4
69,000 miles

[BusyBadger]

It's most likely your catalytic converter going out. There is a Federally mandated 8 yr/80k mile warranty on catalytic converters that is you're on the outside of.

You could try first replacing the sensor and if the code pops after that start looking around for an aftermarket cat.

[Chuck Tribolet]

0140 is the Bank 1 Rear O2 sensor high voltage. Its job is to make sure everything else is working. So don't be in a
rush to fix it, unless you are in state that smog tests (e.g. California) and you have a smog test coming.
Bank1 is starboard side (US passenger's side). High voltage indicates the sensor thinks what's coming out of
the cat is rich. MAYBE you have a bad cat, but the '01s had a problem with wearing out the rear sensor's
prematurely. There's a firmware fix for this. It doesn't fix the bad sensor, but will keep the new one
and the other one alive. Get it, at about the time you replace the sensor. This was done under warrantee
by my dealer. The SES light came on after about 30 minutes towing my boat.

Sensor is cheaper than a cat.

There are aftermarket sensors, but I'd go with the Nissan because it will come with the right plug, no soldering
involved (and I'm a pretty good solderer).


Chuck

[tbsbiker2]

thanks Chuck, I'm getting NO activity report from the scanner I have...connections all look good...I'm going to replace it when I get around to it. I wish this thing got a LITTLE better MPG though...69,000 miles and I'm lucky to get 12 mpg around town and gas is creeping up to close to $4 per gallon here in Chicago.

[Empty V]

Chances are your code is the O2 sensor and not the cat. As Chuck said this is extremely common with the 01's. If you're getting mileage that poor you need to look into it. You could have MAF issues which is also a common 01 issue.

[tbsbiker2]

Thanks for the input..I'm ever hopeful on the MPGs but it never seems to come around. This truck runs smooth as silk...The only thing I have not done is change the plugs (but at 69K I'm assuming as long as it runs well it should be ok? maybe it's worth doing anyway). I had an engine missfire a couple years ago, changed the MAF (thinking that was it)...but it was two of the coils so I have NEW MAF (the Maxima version) AND 6 new coil paks...Cha-CHING! HWY mileage is closer to 19 when / if I get to do any consistant HWY driving.