out of the blue my '01 XC70 won't start. no messages. when I jump started it, it started, but gave me an engine immobilizer message. I turned it off, then it started up fine with both keys. A few days later my wife tried to start it, no go. She said it gave her an urgent brake message (can't remember the exact message). What couuld be going on here? Bad battery, bad ignition switch?

 

I would check the battery voltage. A low or failing battery gives the electronics in these beasts a fit. Our 01 battery went out a while ago, but for a couple of days before it did, the car acted a bit wonky

 

that's exactly what it was, thanks!