I have a 98 Limited, AW4 transmission.

I just replaced the shift solenoids and transmission filter due to the lockup solenoid throwing a code and being out of range (resistance troubleshooting). Within the last year, I have replaced the NSS twice on my own. After the second time, took it to the 4WD shop and had it properly adjusted, more on that below. A quick rundown of problems I'm noticing. At highway speeds, both in OD and 4th without lockup (when solenoid was bad), and sometimes, but rarely at lower cruising speeds, I will get a 500-1k rpm spike. That is the best way I can describe it. I'll be cruising with steady 2.2k and for a split second, with noticeable loss of power transfer to the wheels the rpms will jump to say 3.5k. After the shop adjusted my new NSS, the truck started fine when I left to go home. The next time I tried to start it the same day I had a no start condition, in any gear. I currently have the NSS harness jumped at the back of the NSS side connector, which allows me to start the vehicle and have my reverse lights work.

P0700 Transaxle Control System Malfunction:
From my research this could be related to the NSS code, although it has appeared in the absence of the NSS code. I thought taking care of the solenoid problem would clear this code, it has not. DEX III/Merc trans fluid is clean, new, and at a proper fill level per the work I just did. Any insight is greatly appreciated. Is there any troubleshooting I can do on my own to figure this out?

P0138 O2 Sensor ½ Circuit High:
The O2 sensor located on my cat broke on the harness side. I have a new one, can't get the old one off. I've torched the ever loving s*** out of it until it was glowing, used copious amounts of PB Blaster, etc. It will not budge. Any tips/tricks here?

P1899 Park/Nuetral Switch Performance/Rationality:
This one is driving me insane. Shop adjusted shift linkage and it was fixed for maybe an hour. Wiring on NSS side to connector is in good visual condition. Switch is the second brand new switch I have installed. Shop has offered to troubleshoot, but they are only open during the week and the XJ is currently my work vehicle. I am at a complete loss.

I NEED to be able to clear the CEL, legitimately. I live in IL and my plates expired in feb. I cannot renew my plates until I pass emissions... Thank you in advance for any help!!

 

Bump, is like to get working on this this weekend if possible.

 

Are you using a quality Mopar sensor?
- clean mounting area?

What O2 sensor brand are you using?
- I've used NTK on my 2001, because that is believed to be the original manufacturer.

What are you using on the O2 sensor to remove it? Have you tried a impact socket / breaker bar / large box wrench, after you get it warm? Be careful, you might strip the threads out. Since you are removing the old one anyways, I'd just cut the wires as close to the O2 Sensor as possible for removing it. At this point, it's going to have to come out, because you aren't going to repair it.

 

the NSS is not mopar. The mounting area was cleaned when installed and adjusted, but I will try cleaning it again.

the new, uninstalled o2 sensor is ntk.

I’ve used an o2 socket on a breaker bar, box wrench, adjustable wrench, etc. everything I have really. Can’t use an impact, the end of the sensor is too deep. The wires are already broken off the back of the sensor (that’s why it needs replaced). Thinking of buying a 6pt 22mm closed end wrench and giving that a try, but not too encouraged it will go any different.

 

Well, got the o2 sensor off. Fml, what now???

 

If the wires are broke, what's keeping the O2 Sensor hanging in the air? 🤔🤔🤔

Looks like you need a new cataltic converter. Kolak Performance Off Road is where I got my Magna-Flow converters for my car. I believe he has a Facebook page. Another option is perhaps a universal cataltic converter welded in there, but for I'd guess afew extra dollars & the known quality of a direct fit Magna-Flow, I'd go that route.

I'd also recommend a Mopar NSS.
Excellent choice on the NTK sensor.