Weird Transmisison Issue With 99 S80

[asanab76]

The "Urgent Transmission Service" light recently started showing on my Volvo. I took it in to a Volvo service facility and when they ran the codes it came back as TCM-0087 (Input speed sensor faulty). When they drove the car and looked at it they didn't notice anything was wrong mechanically with the transmission and stated that I needed a fluid flush,replace the gasket, and the left and right axle seals need to be changed. I dropped the pan and did a partial flush of the transmission and replaced the gasket already, but over the past day things have started to get wacky. When I put the key in to the ignition the light on the shifter is on the D and not P and I am unable to start the car. If I leave the key in the ignition for about 30 seconds sometimes the light goes back to P and I am able to start the car, but if not I have try to get the light in the neutral position, start the car, then move it back to Park and restart the car. When I do this the light will sometimes now show in Park but not always. Once the car starts and I drive everything is fine. Shifting is fine without any issues, and car drives normally. I was thinking about disconnecting the battery and see if this resets things back to normal, but at this point I am sort of stumped.

[regent]

Did you disturb the connector to the transmission shift control switch, or the switch itself when you dropped the pan to do fluid and filter? What about the code you had before, is it gone now? Did you check to see if you have any other codes?
I would recommend inspecting that harness for water ingress and/or corrosion (while you have the battery disconnected).

In addition, you need to reset the TCM Fluid Counter after fluid change; this will let the TCM know that there is fresh fluid in there and will preclude the setting of bogus TCM-related codes.

[dcarlson12]

To regent:
How does one go about: "reset the TCM Fluid Counter"?

[regent]

This is done with the VIDA DiCE interface tool and program. Or, you can pay the stealership (like 95 bucks or so). Or maybe an indie shop can do it for less if they are so equipped.