I just replaced a new PNP switch on my 98 S90 (My 70K S90 had flashed arrow 2 months ago and I was told that
I have to replace the PNP switch to fix the problem). After replacing, the gear cannot be engaged. If I pull out the
fuse for transmission control module (5A fuse located in the #1 spot in fuse Box B) and then put it back, I can
engage the gear but only for a couple of minutes. Then if I pull out/put back the same fuse again, I can drive another
1 or 2 minutes and then the tranny backs to netural position again (not engaged). Can somebody tell me what was
wrong with my tranny? Is it possible that my transimssion control module has problem? I googled the topic and
found somebody mentioned "transmission computer". Are the "transmission computer" and "transmission control module"
(or control unit) the same thing? Where is it located? Thanks.

 

Did you set the PNP up right?

 

Tech, I installed PNP switch and adjusted it according to your suggestion "When you install the new one hook an Ohm meter to the red and blue wires and make sure that it that beeps and make sure it is beeping when you tighten the bolt" (BTW, thanks for your advice).
I did hear the beeps when I rotated the PNP switch to a certain position and then I tighted the bolt. Do I need to do other adjustments?
Thanks.

 

Does a replaced transmission control module require programming

 

I assume you are just replacing the tranny and nothing else? some models require a driving cycle to reset the fuzzy logic. Check out https://www.matthewsvolvosite.com/drive-cycle/

 

Not on a 1998. What year and model is your car?