no bus; check engine

I have a problem with my '99 Durango 5,9l. At hot day's the engine shut off itself and a get the message (where the miles normaly are) "no bus" and the check engine light is coming up for a few seconds. The computer test in cold conditions are all ok. No prob at all in cold condition.

Check The Previous Postings. Bad Pcm. Covered Under Federal Emissions Warranty 8yrs, 80k Miles. Tell Dealer To Let Truck Run Otherwise No Codes Will Appear Because When It Shuts Off It Deletes All Stored Codes