I was having this Parking Brake Temporarily Unavailable issue (though it could still be set manually or through the configuration that causes it to engage when the car is turned off) along with "Auto Hold Requires Service." I do not recall exactly when it showed up so I do not know what caused it. I believe the auto parking break engaged briefly on the moving track of a car wash.
I realize this thread is a little old, but wanted to leave this solution here for anyone else who has these issues going forward, as this community has helped me out several times. I had no prior experience with any of this (except the fuse). I do not even think I ever had cause to charge a car battery.
After trying a couple things, I solved it without going to the shop. Notably, this was just yesterday so I suppose it could be a temporary fix. I did not update any software.
1. One person indicated that removing the fuse worked for them. I tried it with various ignition positions, when the car had been off for 15 minutes, etc. Did not work.
2. I saw a few posts about it being related to battery charge/voltage issues. This is far more commonly associated witht the loss of the "Start/Stop" function. I purchased a charger (with a stop/start button) based on recommendations on here. I fully charged the battery a few times and it did not have any effect on these two errors. It did, however, cause Stop/Start to start functioning as expected. I had to drive at least 75 miles to get it to charge up enough and function, though it usually did not function at all. Now it seems to charge up more readily by driving and is available a few times before it needs to be charged again.
3. I learned that you can use the free version of VDASH (Google it) along with a simple ethernet to OBD2 to Ethernet cable (Amazon---make sure it's the Volvo SPA one----it's usually red) to reset the parking brake (I am not sure if there are other reasons why one might want to). Also, my laptop is relatively new and only has an ethernet port if one buys the (very expensive) dock, so I had to purchase a USB C to Ethernet adapter) to use inline with the cable).
DO NOT DO ALL THE RANDOM STUFF I DESCRIBE BELOW---I was prepared for the possibility that I could make everything worse and possible render the car entirely inoperable and assumed that risk.
First Try: I followed the procedure (in another post on here---search for VDASH). On the first day VDASH auto updated upon connecting to the network (something that I would like to disable for the time being). I tried different permutations of the procedure (for instance, that person said to turn the car on and then off before connecting the ethernet end---for me it didn't work). In any event, I could not get VDASH to recognize the connection and detect the car. It told me that I did not have the proper drivers connected, but downloading and installing them, restarting etc., did not clear that warning in VDASH or have any effect otherwise.
Second Try: I did some more research and found out (in other contexts) that people who were able to connect previously, couldn't once VDASH had updated (this was sometime in the past, so likely not the same update I received). I opened a ticket with (i.e., contacted) the creators of the software via their website, explained what I had read, and asked them if I could obtain an older version. The next day, I had not yet received a response (I believe they are in Poland or around there) so I went to try it again.
VDASH updated as soon as I started it up, so perhaps that was their response. It recognized the cable and car and started the scanning process (which takes a few minutes and lagged around 28%). The first time it scanned it lost connection and produced a number of errors. With the knowledge that I had no knowledge of what I was doing, I clicked through the different modules until I found one that had options related to brakes. As mentioned, it had lost connection during the scanning process, so I got errors about it not being able to communicate with the BCM (brake control module, I believe). Some other functions worked, so I was a little concerned that the communication error was due to the problem with the E-brake. I disconnected, restarted, reconnected and it completed the scan. It was able to communicated with the E-Break and I again pushed all the options in no particular order (except where it indicated to release the ebrake before pushing a certain button or buttons). I started getting more errors (esc needs service, for example) but that was to be expected as I was opening all the different control module sections and pushing all the available buttons just to play around (and accepting the risk that I would make the car inoperable). That's how I learned to use a computer when I was little and many other things since). I panicked a bit. On the main car page (not the home page---there are tabs at the top) there was a list of all the trouble codes detected during the scan. Underneath there were a few more buttons. One was clear all diagnostic trouble codes and one was clear BCM trouble codes. I reset the BCM first and then all all of the DNCs. Then refreshed and still had some, including the parking brake related ones. I disconnected, restarted the car (the errors were still popping up when I started the car, including the additional ones I had caused by randomly pushing functions), reconnected, refreshed the DTC scanned and still got some related to the E-Brake. I went through the various functions under BCM again. I cleared DTCs again, restarted, refreshed, and there were only a dozen DTCs left. I cleared one more time and it cleared all but one. Good enough for me. I shut down the car, hooked it up to the charger because this diag process is said to take a lot of juice, and decided to leave the car alone for a while. Then I drank a little and forgot about it for a couple hours. When I finally went back out, checked and disconnected the charger, and started her up, all the errors were gone.
Note:
First day I was using a different hub that supplied power to the laptop and had an ethernet port. The send/receive lights were doing their thing on the port on the hub, so I don't know if that was the issue. Just in case, I went to Best Buy and purchased the direct adapter.
Also, between days, I had found something that recommended plugging your laptop in to a wall charger (not the car), so I ran an extension cord and did so. It also said not to have anything plugged into any of the 12-v outlets (which I didn't in either instance).
Finally, when I got it to work at the end, the ignition was in position 2, but the car was not running. I had read this somewhere, but had been experimenting with having the car running and turning it off (as someone had directed to do in order to get VDASH to connect).
I will come back and clean up this post. I don't have the time right now.
