Last week, my S40 T5 Turbo stalled with the immobilzer message; it started right up and this has not happened again. However, today it quit twice while I was driving. The first time was not a full stall - it lost power for a fraction of a second and picked up again right away. The second time was a full stall, but it started right up. There are NO messages. My mechanic (certified) put in a new alternator a couple of weeks ago because it was bad and throwing alerts. He said the immobilzer message might have been a "ghost" code, but now I wonder. The battery is about a year old. Otherwise, it runs great. I worry that it will really die and strand me somewhere. I know it has to be flatbeded, not towed. Again, there are NO messages or alerts. Ideas? TY

 

when you say no messages or alerts are you saying on the dash? Did you have the car scanned for any stored codes?

 

Yes, no messages or alerts on the dash. My mechanic will scan for codes tomorrow. His concern is that the CEM may be on its way out. . .? He thinks he will be able to determine if this is the case, Any other ideas? TY

 

I assume your S40 is basically similar to my V70, which developed a stall which got steadily more frequent. Volvo delalers and specialist independents could offer no cure other than leave it with us and we will test drive it. Having already told them in wrtitng all that they would learn from a test drive, I decided to do some research of my own. I found a solution on line - the cure cost me £7.50 and fifteen minutes of my time. I bought a spray can of Wynne's Air intake and Carburettor Cleaner, dismantled the throttle box (an easy operation), sprayed the interior throughly to disolve the accumulated carbon deposits, reassembled it, ran the engine for thirty seconds, dismantled the throttle box once again and sprayed for ten seconds and reassembled the throttle box, The engine runs perfectly without stalling.
Hope this helps.