1997 XK 4.0 4WD NP231

Description of code is “Transmission range sensor “A” circuit (PRNDL input).”

Symptom is no downshifting automatically, but shifts fine when manually selected (not sure if it ever goes into 1st).

Clean NSS and grounds?
Anything else?

 

I'd test the TPS sensor as well.

 

To follow up:

The shifting issue can be attributed to low trans fluid. New to me vehicle, a trans cooler line leak has now been fixed.

Due to the CEL and code, I prepared to remove and clean the NSS, but as I started unbolting it, I realized it looked brand new, and figured the PO had replaced it for the same reason. Tracing wiring it seemed one of the two grounds located below the coil was associated. After cleaning both grounds and clearing the CEL, after a week of driving it the problem seems to be resolved.

Hope this helps someone in the future.

Cheers!

 

Definitely clean the sensor and grounds. I'd check the fuse while your at it, should be #10. My '99 threw this code instantly every time I cleared it, several times in a row. Turns out I forgot to plug the fuse back in after checking several of them. Of course if it blew the fuse you'll have to investigate why it blew and address the issue. Hope this helps, good luck.