I had my bank 1 rear O2 (due to a P0037 code) replaced yesterday and the ECU reset to clear the code. Made several short trips and a couple longer (10 miles each) drives since then. I took my car in today to get the yearly inspection and the O2 and Catalyst monitors were still reading "not ready". All other monitors were ready.

Still had to pay and I get 1 free retest as long as I bring it back in the next 15 days. They said they'd hook their reader up to make sure all monitors are ready so I don't waste my freebie but it is still a PITA to have to go back.

Reading through a few threads, there doesn't seem to be any real consensus as to how far you have to drive or how many on/off cycles it takes until the monitors are all ready for testing.

 

There is a drive cycle you can perform. I think it is available in the service manual, but not sure. Anyhow, yes, sometimes it can take 200-300 miles of driving over several days to reset the monitors. Parts store scanners can also check the readiness monitors for you.

 

It's all about how you drive, not just on how much you drive.

Look at EC-83 and EC-84.

 

exactly... you need to do slow driving, stops, highway speeds. it cant all be the same consistent every day driving.
take your car out, drive around 30-35 for a while. stopping occasionaly for about 10-20 secs. then take it on the highway for a couple miles, but dont go above 70. you shouldnt have to drive many miles if youve already been drivin around a bit

 

I dont think its just driving I remember reading a recent post about this and someone posted a section of the FSM (I think) and it has a lot to do with tempature specificaly fuel temp. There were a few different cycles that yeilded different mile markers for full functionality. I'll see if I can find it.

 

Did you review the FSM pages mentioned in post #3?

 

http://forums.maxima.org/5th-generat...tting-ecu.html
here it is I had to turn my laptop sideways to read it tho lol

 

over at our dealership i am told that you need to drive the vehicle at a steady 55-60mph for several miles. we just drive it on a nearby expressway for a round trip total of about 15 miles, which usually does the trick 90% of the time. also you do not need all of the ready monitors to set, you can have one incomplete monitor, for cars after 2000 i believe, two incompletes for pre-2000 and still pass emissions.

 

I guess I drove enough tonight because I popped a P0420 code.

Reset the code, drove home. 3 monitors are still showing not ready, two of them being O2 and catalyst.

First step if the P0420 comes back is trying a spark plug non-fouler. Bank 1 rear O2 is new so that should be the issue. I did some searching and couldn't find a definitive answer whether the reflash would help. I have no idea how current my ECU is with regards to updates.

 

how many miles on the car scottwax?

 

147,248 as of two minutes ago when I got home. I guess it would be somewhat normal with the mileage to have the cats start going bad, just that the timing is horrible. My inspection sticker expires at the end of this month.

 

Time for an O2 sim... :-)

 

i had the same problem had my cats replaced a day before the inspection and my inspection was till this month , so the guy told me to throw a fuel injection cleaner and fill the tank that did the trick after a few drives around the block. my car is at 133k so yea its about that time.

 

Probably better to replace the precats, no doubt there is some clogging going on by now. I'd get headers but right now I have other things more important (like $1600 still owed from my surgery).

Anyway, I did pass, only one not ready was "catalyst" so I got my sticker. I plugged in my OBD reader just for fun a little later and while "catalyst" still said not ready, I had a pending P0420 code. Came back yesterday with an SES light (2 trip code), reset it and despite now driving 140 or so miles, no codes. Go figure.

 

an aftermarket y-pipe would have taken care of it (if im not mistaken)

 

what exactly does the sim do? simulate the signal from the o2s to the ecu? would it help if i got a fail cat, and a failed heater senser reading?

 

Yes.
Yes.
No.

For the heater, you'll need a resistor.

 

or would it be best for the car if i replaced those sensers first?

 

If you actually have a bad cat, it is best to replace it. When they clog up they can really affect mileage and performance.

If I ever get headers or if I need to get my car to pass on the cheap, then I'd go with O2 sims.

 

I keep my address rural Suckers! :P (have 02 sims anyway haha)

 

soooo, with all this reading How many readiness monitors are on our 5th gen cars, I had to reset my infamous p0430 code today but ive been following the instructions here on the forums and I managed to get 7 readiness monitors set properly, according to my 100 dollar actron generic scan tool...........

If seven is all I need I will take the car to the emissions spot tomorrow morning.
I could have sworn there were only 7 readiness monitors

 

O2 sims worked for my car. Was popping a P0420 and P0430. Slapped the SIM on and it passed w/o a problem. This was also w/ the O/2 sensors OUT (ziptied next to the front engine mount) of the exhaust and the catalytic converter removed (straight pipe) Gotta love saving the environment! All this in the same day too. The only time the car wont set the readiness monitors is when there's something wrong. The ECU is pretty touchy with the O2 sensors especially. I was actually "ghosting" those two codes and only found out after doing the Code Reading Procedure after coming home the fourth time from the emissions place.

 

sooo, i got a MIL for my rear bank o2 sensor. i heard if i disconnect the neg battery terminal for about a half hour, the light will turn off, and i should be able to pass emissions if i get to the shop fast enough. anyone else hear about this? im concerned the monitors will be "not ready"

 

Spend $40 for a code reader which can give you IM Readiness status such as $40 Autel unit from Amazon. That way you will *KNOW* if your emission status is ready or not *BEFORE* you take it in for inspection.

- Vikas

 

I have one, read all most posts in this thread. That's how I knew I had the P0420 code. Just didn't think to check for codes before the first inspection because it had long enough to reset the computer.

I ended up getting a pair of precats from someone here who took theirs off at 60k miles (put headers on the car) but haven't swapped them out yet. No lift and no air tools so I may just let my mechanic do the work since he said it would be 2 hours labor tops. The code comes and goes. Sometimes it pops 2-3 times in a row after a reset within 40-60 miles and other times, like both road trips I've taken this summer (one 2000 miles, the other just over 500), no codes at all. Currently haven't had it pop up now for more than a week. Go figure.

 

you've got to have most of the readiness monitors set