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Nss replaced now it rolls in park

willsmysticcobra

NAXJA Forum User
Location
Lake Zurich IL
hey guys im working on a 1999 xj AW4


I bought an ebay brand new in box NSS and went to work extracting the old one. Well it broke and to get by for a few days we bypassed the NSS by jumping the wires on the stock OEM harness NSS side , not the Jeep's engine harness side obviously. Now the CEL came on ( P0705 )

Installed the new NSS today, adjusted it spot on so the lines line up on the shaft and the NSS, and the reverse lights work just fine. Touched the two battery cables together, hopped in and started it up in Park. Fired right up, but after 10 seconds the CEL came back on. Upon releasing the Parking brake, the AW4 auto still let the jeep roll as if it was in Neutral.

I am no rookie when it comes to working on jeeps, I cycled through all the gears and when it went in park, I can hear the syncros move etc ( I know its physically in park so we can rule out the linkage)

I guess my main guess would be a defective switch, still throwing the range selector CEL after replacement, it wont start in neutral, only Park, and the linkage seems a ok. Also in the BEST of my knowledge it is adjusted properly as I have reverse lights when placed in reverse.


ANY guesses or input are greatly appreciated!
 
Installed the new NSS today, adjusted it spot on so the lines line up on the shaft and the NSS, and the reverse lights work just fine. Touched the two battery cables together, hopped in and started it up in Park. Fired right up, but after 10 seconds the CEL came back on.

Even if the fault is corrected immediately, you would have to clear the code from history or go through a certain number of drive cycles before the MIL will go out. Now, it sounds like you touched the positive and negative cable together to clear the capacitors in the PCM. This is not the recommended way to clear codes. I would disconnect the cables and leave them overnight or run to autozone to use their free scan tool.

I am no rookie when it comes to working on jeeps, I cycled through all the gears and when it went in park, I can hear the syncros move etc ( I know its physically in park so we can rule out the linkage)

The AW4 does not have synchronizers.....you're thinking manual tranmission. It has a parking pawl that prevents the planetary gearsets from turning. I would be suspiscious of the jumper wire you added to bypass the NSS while waiting for a new one or the linkage that you disconnected for NSS adjustment. You may also have an internal transmission problem if its not holding in park.
 
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Ya I mean I left the two cables directly on top of one another for the ecu to clear. Upon start up, the CEL wasnt present, yet came on 10 seconds later. The thing I am super stumped about is why my Jeep still rolls freely in Park gear. Like I mentioned it wont start in Neutral either, yet it fires up perfectly in Park, where the stock 14 yr old NSS would start to falter in starting in Park but would always turn over in Neutral.
 
The function of the parking mechanism has nothing to do with the NSS switch. The parking paw is internal to the transmission and is non electronic. The shifter linkage is incorrectly adjusted and not fully engaging in park or you have internal transmission problems.
 
Ya I have been reading that.... I will admit, a few times I clamped down one the rod that the NSS slides on and physically took it out of gear. Do we think that could have taken it out of adjustment, or did I break the parking pawl?
 
Parking pawls are almost impossible to break. I've see people slam it in park while driving. It made one hell of a racket but afterwards, everything still worked. I vote for out of adjustment on the linkage.
 
I believe I had the jeep in neutral and when I clamped the vicegrip onto the collar that fused it self to the shaft. Tried my hardest to get it off and it turned to either drive or reverse, which ever way I was twisting.

The best way to figure this one out is to pop off the linkage on the drivers side and try and adjust it into park I suppose... wonder if thats aiding the CEL from still shining, because the jeep wont start in Neutral... the trans/ tcm may think its somewhere else
 
Have not really tried anything in 1-2. I am going to follow the various write ups on how to pop off the linkage and adjust it and go from there. I am dubious if that will clear up the check engine light , but it makes technical sense that I move something out of adjustment when I was trying to pull the broken NSS part off the shaft.

Really appreciate all the input and troubleshooting here guys. Puts my mind to ease that I can get this jeep up and going with Park for the upcoming cold and snowy Chicago winter
 
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