Two problems related to engine shut off without warning have been reported for the 1999 Volvo S80. The most recently reported issues are listed below.
I've had this problem for months now. The car shuts down and won't restart! I been taking off the battery and letting it sit over night, then putting cables back on to get it to restart! today I drove it for a mile and parked it and while it was running it shut down again! most of the time it shuts down when I'm driving and I lose brake control!.
I was driving on the highway and I felt a loss of power. I pulled over and the car shut down. I tried starting it but it backfired and stalled. It took me a while to find out what was going wrong. Finally I unplugged the maf (mass air flow sensor) and drove back home with an extremely weak and dangerous car. I drove it like that for a few days. I had no choice because I had no other way to go to school. I changed the maf sensor but it didn't do much. I went to a local shop and had the throttle body cleaned. I could now drive with my maf plugged in but it wouldn't drive properly and would occasionally stall. I learned that Volvo had alot of etm (electronic throttle module/body) failures on their S80's. So they issued a recall that they apparently have a hard time respecting. I went to a Volvo dealership (Volvo laval) one of the worst dealerships I've been through, by the way. The service manager didn't want to know nothing about my car and simply told me my warranty was over (although it was supposed to expire may 26th, it was actually may 19th that day, so I had a week left). He didn't want to know nothing about my situation and cut short and asked me and my friend to leave after insulting us. Now my car stalls occasionally and has a rough idle. The dealership didn't even want to diagnose the car for free although it is a design mistake by Volvo. I now have the choice of either spending 1600$+ on a throttle module or just drive my car and deal with the stalling.