One problem related to front suspension wheel bearing has been reported for the 2004 Saturn ION. The most recently reported issues are listed below.
Received first Saturn Ion 04 and within one week of purchase car was displaying clear signs of either an electrical or computer problem. Was replaced with a second Ion o4. Noticed a strange clunking sound. Brought car in at 3600 miles, and it was transmission mounts, wheel bearings, axels, and break rotors. Car was returned with a broken piece in the interior, and smelling of burning plastic. I believe that this car is defective, and Saturn refuses to do anything other than make repairs under warranty. I think that I should be issued a refund, due to faulty construction.