1998 Dakota, 5.2, auto, 49 state emissions, 200000 miles. Had the oxygen sensor monitors that were incomplete. I replaced upstream and downstream sensors with Densos. Battery was disconnected, all monitors reset. Now has 410 miles on it, the only test not complete was Catalyst Mon. Now it's changed to Oxygen Sensor mon and oxygen sensor htr incomplete. Battery has not been disconnected. What would cause these to reset on their own? I can't smog test the truck with any incomplete monitors. Any insight?

PS, no lights or codes are coming up from a scan

 

California doesn't allow any incompletes? Here in TX, 2000 newer can have one incomplete, 1999 and older can have 2 incomplete.

1. Factory O2's are NTK, not Denso. So you might have some issues there.
2. Chrysler's "Drive Cycles" are really vague. Sometimes I can get O2's to set in a single 20 minute drive, sometimes it takes days. Catalyst Monitor is almost always my 1 passing incomplete.

 

Maybe the cat is dead?

 

Yeah, I had thought about that. But it's a newer cat, from Magnaflow I think. It passed no problem a couple of years ago.
Honestly, if it needs a new cat or something major this truck may just end up going to a junkyard. It's got zero rust, no wrecks, good paint, nice interior, but so many little issues pop up. Or it'll be a donor chassis for a '40's truck I have

 

If it's clean, it's worth easily 4K outside of California with the 5.2 at 200K miles.

Magnaflow should pass no problem. I know they don't have the cell count of a stock cat (I have a magnaflow on my procharged dakota), but should still pass.

One thing you noted. It has 49 state emissions. What is the California code of leniency for that, since it's not an original Cali truck?

Everything I see says that Cali has to meet the federal minimum of one incomplete monitor and still pass.

So as long as you only have one I/M saying "not ready", it should pass.

http://justsmogs.com/2017/02/februar...mog-check-faq/

https://www.bar.ca.gov/Industry/OBD_...erence#passThe number of incomplete OBD readiness monitors that are allowed to pass the OBD test portion of a Smog Check inspection are provided below.
Model Year Fuel Type Number of Incomplete Monitors
Allowed to Pass OBD Test1
1996-1999 Gas2 Any one3
2000 and newer Gas2 Evaporative system3
1998-2006 Diesel Zero
2007 and newer Diesel Any two

 

So the thing is when it was smogged tested a few months ago it actually ran super clean but it only failed because of the incomplete monitors.
So the non-California admissions isn't such an issue. It's more of that. The monitors weren't complete. Numbers wise it runs super clean. According to the report I got it was originally shipped to the Denver area.
I'll have to look further into that one incomplete monitor thing. If that's the case then maybe I can get it to work.

 

Okay, so a follow up. Finally got around to sorting this out after I let the truck sit for a few months. I replaced the Bosch O2 sensors with NTK sensors since those are OEM. I drove about 1000 miles, even took a 4 hour round trip drive to Central California to really get everything hot and burn off stuff from sitting. The truck has now passed. Lesson learned in case anybody stumbles across this issue in the future, use OEM. I seen it said multiple times and I'll reaffirm what others have said, always go OEM.

 

You first said you replaced them with Densos. Those, I believe are pretty close to NTK. Bosch sensors (of just about any type) don't work well with these trucks. Magnethead hit the nail on the head.

 

You are correct, it was Densos. See, been so long trying to get this smog this sorted I forgot the brand. But at least it's all solved. Monday it goes to the shop to get the AC charged up.