1998 S90 Transmission Problems

S90-Owner · Post by **S90-Owner** » 15 Jun 2013, 09:24

I recently bought a 1998 Volvo S90 and about a week after regular driving the yellow flashing arrow appeared on the dash and now the speedometer only works half the time now. Because the car was driving fine then I didn't think to much about it, however I drove it yesterday I noticed it would sometimes stay in gears to long, particularly 1st and 2nd gear. Also when ever I came to a complete stop it seemed like it skipped 1st gear and go straight into 2nd. From what I've researched its most likely the pnp switch but I want to be sure so I dont spend a few hours replacing something that won't fix the problem. Any help would be greatly appreciated!

Post by **precopster** » 15 Jun 2013, 17:16

Speedo gets signal from rear differential sensor so not related to trans. There are a couple of capacitors on the speedo circuit board that regularly fail. Replacing them with tantalum type is a more permanent fix.

The PNP would be the most likely culprit of the shifting problem. There's a PNP tutorial for the 850 which internally is identical. The PNP wiring snakes over the top of the trans to a pair of square connectors.

S90-Owner · Post by **S90-Owner** » 16 Jun 2013, 13:18

Thank you!!!!!

Post by **jimmy57** » 16 Jun 2013, 13:23

Trans gets VSS from speedo. Speedo circuit converts it from analog 48 pulse/rev input from diff sensor to digital 48 pulse/rev. and 12 pulse/rev. for TCM, cruise control module, and radio for speed based volume control.
ECC also uses it for fan speed regulation when fresh air is the air input source for climate.

Post by **precopster** » 16 Jun 2013, 15:05

My speedo was constantly (intermittently) failing on my old '93 960 and it resulted in no cruise control. However I never got a flashing arrow through the whole ordeal. Perhaps my TCM software wasn't designed with this failure in mind. Later TCM sw may be able to sense VSS absence.

Reading your OBDII codes may help you narrow it down further.