Update: today after all my work, I started it for the first time. It started and ran well, but... I've got a PO135 Oxygen Sensor Heater fault on the brant new NTK sensor. Think the computer needs to relearn it or did I get a bad sensor out of the box?

 

See if the heater circuit is getting power. Might be as simple as a blown fuse.

 

Thanks. I'll look for that fuse. Someone did say that it's the same fuse that powers the ignition coils, so if it starts and runs, it's not the fuse but rather a faulty O2 sensor. But I'll look into it anyway. A search shows it may be fuse #3 if it is the fuse.
Here are the choices in my fuse block. I checked #24. It looked good. Not open or burnt.

 

Here is what AI says:

My thought at this point is that since the original looked great and was working fine, I'll just put it back in and run it until it goes bad. When it goes bad, I'll replace it with Genuine Mopar. And then if that fixes the issue, I'll have solid data for NTK warranty.

 

After a little more digging... since I now I have the actual part number of the original in hand, it would appear DENSO 234-4634 is the OE replacement part. As you can see from the RockAuto link, it is in stock. Says it interchanges to my part #56028233AA.

RockAuto also has Mopar part #56028233AA and identifies it as California emissions. My Durango was built in Canada for the Canadian market. Maybe Canada and California are all in the same? Wondering if all of this is throwing me a curve ball?

Mopar Parts Giant also shows Mopar 56028233AA as a 1999-2000 only part. It may also be that this is yet another early 4.7L thing and the later parts with a later blanket OE interchange number does not cut it. See also my valve spring findings.

 

I have seen more issues with bosch sensors than any other brand. NTK and Denso were both OEM at one point or another. Check fuse 24.

 

Here:

 

Okay. I ordered the following two Denso sensors. Notice these O2 sensors are very make and model year specific...

Denso OE Part # ---------- Mopar Part #----------------------------------------------------------------- Make/Model/Year ---------------------------------------------------------------------------------- Location ---------------
Denso #234-4634 ------ Mopar #56028233AA ------- Dodge Dakota 2000 4.7 V8 -------- Dodge Durango 2000 4.7 V8 ------ Jeep Grand Cherokee 1999-2000 4.7 V8 --------------------- Before Catalyst
Denso #234-4761 ------ Mopar #56028234AA ------------------------------------ 2000 Dodge Dakota/Durango 4.7L ----------------------------------------------------------------------------- Left Side After Catalyst

Got them both from RockAuto for less than $100/shipped...

Because these are so specific, my theory is that the computer is looking for specific values. Fingers crossed.

 

A lot of times, the differences are in the length of the pigtail....

I would swap out the fuse anyway..... "Looks good" and "Is good" can be two entirely different things.

 

I used Denso 234-4718 for both. No issues. I think I cross referenced the Mopar number on the Denso site.



On a different note:

I keep good records. I replaced these things on 10-3-20. Almost six years ago and it feels like it was last year! I'm having trouble believing it's been that long. I don't know if it's the Covid effect or what, but the early 2020's were all a blur and my sense of time for that whole period is warped. Maybe demetia starting to set in? Jeez.