Engine turns off at random, no fault codes.

[DanSC]

I had a random shutdown issue on my 2001 S80, which I traced to an intermittent connection in the circuit that turns on the ECM relay (thread link). The base bracket (part 9456590) holding the ECM was loose, causing the circuit to intermittently break, which turned off the relay, which killed the engine.

My diagnosis was to use a relay tester/manual switch relay and see if that would make the engine reliably run.

[pranayama]

Did you guys try doing the Glove test and looking at the PCV system. The glove when put on the oil cap should inflate on idle telling that there is issue with the PCV system or the catch box to be more specific.