Autonomous

Took our 1999 Cherokee in for inspection for the third time, I still get three failures: Catalyst Status = Not Complete, Oxygen Status = Not Complete, and Oxygen Heater Status = Not Complete.

We bought this a year ago with a brand new inspection sticker on it, so we thought it was all good. The battery has been disconnected a few times due to electrical repairs. I just put in a new thermostat a couple days ago because the old one had "failed open" and the XJ wouldn't reach proper running temp.

The inspection place says "you may need a new computer" but I think I probably need to drive it a couple hundred miles now that it is getting up to proper temperature. There is supposedly some driving cycles I should run to properly re-calibrate everything. What do you guys think?

Finally, does anyone know the best affordable tool I could buy to check these myself? I think its about time to get some sort of scan tool so I don't go broke having to pay for inspection only to find out its still not ready.

Bustedback

It sounds like you may have an o2 sensor problem, is the check engine light on?

Autonomous

No CEL's or anything weird. Runs great.

cookiemech

If you've been disconnecting the battery, you will need to drive it through several "cycles" (I don't know the specifics for the Jeep, but probably three 20-mile trips or so) before the OBD-II recognizes that all of the parameters related to emissions are within spec.

The "not ready" status is normal if you've disconnected the battery; it's the same as if you connected the scan tool and cleared any trouble codes.

JeepingDan

Put about 60 to 100 miles on it over a few days and then obd status should be complete and you will pass smog as long as there are no cel's related to emissions.
Just remember disconnecting the battery will reset it again and you will have to go through the whole cycle again.

hghplnsdrftr

The clock is ticking on my fixing this thing...I have the same issues on a 2001 Cherokee...I ran it yesterday for 135 miles with a dinner break at the half way point...Is this fix a matter of driving several short trips? I was orig told to jusy put miles on it and never had enough miles for thing to reset so I drove a longer round trip down the highway. This morning went for a retest because there were no lights after my trip yesterday...The guy at the inspection place said is showed the same thing.....Evap....not ready.......O2 sens.....not ready..........they told me that I may need to take it to a dealer and get a computer test done?????...I have replaced eveything in the evap system from gas cap,fuel pump,charcoal filter,sylinoid,and canister..HELP!...

413maxwedge

Short trips you need to cycle the jeep, this means starts and stops.If you want PM me when you get the codes and I can tell you what they are right from the book.

Autonomous

Thanks a lot for the offer.
I bought an OBDII adapter that sends the info to my phone via Bluetooth. I then downloaded TORQUE app for my DROID X. I drove until the sensors completed their tests, then killed the jeep and restarted.
The codes weren't being stored, so I replaced the ground cables with 2 gauge welding cable and wire-wheeled the ground points on the body this weekend.
Hooked everything up and restarted TORQUE and drove to the store and back, everything was READY and COMPLETE. Restarted and everything had saved properly. Going to get inspected this coming weekend.

Autonomous

My advice, at minimum undo the 2 grounds to your battery and clean both ends, also clean the grounding strap from the firewall to the head in drivers side. Make sure you have between 3/4 and 1/2 a tank of gas (they say that's when the EGR and vacuum tests run). Then just drive a tank of gas and you should be good. AutoZone should be able to tell you if your system reads READY or COMPLETE if you ask them nicely. Tell them not to clear any codes.

retread

a cycle is determined by operating temperature not mileage don't shut down when inline for the test

Autonomous

Passed emissions Friday. Told the "mechanic" next time to advise people to check or redo their grounds before they shell out cash for a new computer.

WINNING, DUH!

srjk

I know this is an old thread, but my experience reflects some veracity to this. Had 2 sensors not ready for the past 2 weeks (o2 and cat), already changed to new battery and 2 new 02 sensors (1996 xj), and drove for over 300 miles... nothing. Finally disconnected the negative terminal, connected the positive to the body for about a minute - read somewhere that this "clears" the PCM, cleaned and re-connected the negative terminal. Drove for just 8 miles, and got my o2 sensor ready. I live in CA, and 1 missing sensor (which is my cat) is enough for me to pass. Will go to the smog center tomorrow morning.

BTW, I use the Elm327 plus OBD Fusion app for the iPhone - total $30 to monitor my ODB2, this setup is pretty damn good.