One problem related to automatic transmission control module has been reported for the 2004 Saturn ION. The most recently reported issues are listed below.
While driving approximately 65-70 mph on an interstate, my vehicle just died - no warning. This was the second time it had happened. There is no power & must be pulled off the road & restarted. This is a very dangerous condition - rapid deceleration on a congested highway could be fatal. When I took it to the dealer, they told me nothing showed up on the computer, therefore nothing was wrong with the car. Talking to the Saturn customer service rep returned the same response. I am very afraid to drive this vehicle, it is a very hazardous condition and the car is only one year old. It is a 2004 Saturn Ion. The dealer refuses to replace anything because "nothing is wrong.