My 2002 Interceptor is doing the same thing except my code is 5-3. I "Googled" Ford airbag diagnostic codes and found
Airbag codes - Automotive Message Forums
Here is the chart listed from that site.
Air Bag Fault Code Table
AIR BAG DIAGNOSTIC MONITOR FAULT CODE PRIORITY TABLE
Priority Code Component/Fault Description
Highest -- No Air Bag Lamp - Inoperative Lamp Circuit or No Ignition Voltage to Diagnostic Monitor
| -- Continuous Air Bag Lamp - Diagnostic Monitor Disconnected or Inoperative
| 12 Low Battery Voltage
| 13 Air Bag Circuit or Crash Sensor Circuit - Shorted to Ground
| 21 Safing Sensor - Not Mounted on Vehicle Properly
| 22 Safing Sensor Output Circuit - Shorted to Battery Voltage
| 23 Safing Sensor Input Feed/Return Circuit Open
| 24 Open in Circuit 944B or Low Resistance in Crash Sensor(s)
| 32 Driver Side Air Bag/Safing Sensor Circuit - High Resistance or Open
| 33 Pin 7 Not Grounded at Diagnostic Monitor
| 34 Driver Side Air Bag/Safing Sensor Circuit - Low Resistance or Shorted
| 35 Low Resistance Across Pins 8 and 9 at Diagnostic Monitor
| 41 Crash Sensor Circuit - High Resistance or Open
| 44 RH Crash Sensor - Not Mounted to Vehicle Properly
| 45 Center Radiator Crash Sensor - Not Mounted to Vehicle Properly
| 46 LH Crash Sensor - Not Mounted to Vehicle Properly
| 51 Diagnostic Monitor Internal Thermal Fuse - Blown and Short to Ground No Longer Exists
| 52 Backup Power Supply - Voltage Boost Fault
| 53 Internal Diagnostic Monitor Fault
Lowest -- Rapid Continuous Flashing of Air Bag Lamp - All Crash Sensors Disconnected
Hope this helps.
