G8 total car failure ..while driving!!

[JAWDRPNG8]

Going down the freeway..had my car "stall" at 65 mph
got off .free way coasting in neutral...
parked...it ..
tried to turn over...nothing..nada
Car has been sitting at Dearler in nor cali ...since THURSDAY>>
help!!
no error codes found since OBD II cant connect to comptuer

[g8_795]

Did you have any tunes or anything done to the car?

[MANOFSTEEL69]

I think I remember reading some of the earlier posts on the other forums about the battery terminals being pretty loose. I know it seems like a pretty simple thing, but the simple things are usually the most over looked.

[GRRRR8]

If the cables were loose, it can cause voltage spikes that wipe out ecm, bcms.

[-Ray-]

There should be voltage suppression.

[GRRRR8]

The manufacturers have not fixed that issue yet. I get them in all the time with bad batteries that have been jumped and the ecm is toasted.

[wreckwriter]

Just a loose cable by itself could cause this I think. You could tell if this was the problem by tightening the cables, recharging battery etc. If you can get power, check to see if the little Onstar light in the mirror is red. If so, you lost battery power while key was on. Side effect is Onstar backup battery is now trashed and must be replaced.