1994 Mustang Air Bag Flashing Code 12

GLRSR1951

New Member
Jul 22, 2018
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My 1994 Mustang is flashing an Air Bag Code 12 and blows the number 4 fuse as soon as I turn on the ignition. It appears that the Code 12 is triggered when the “Air Bag Diagnostic Module” sees low voltage. The wiring diagram I have shows that fuse powering the Air Bag Diagnostic Module exclusively. Unless anyone can help with a better plan, I am going to unplug the module connectors and see if the fuse still blows. Anyone see a problem with this? What are the chances of damaging other components, like unintended air bag deployment?
 
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jozsefsz

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Refer to this to troubleshoot your problem. http://www.veryuseful.com/mustang/tech/airBag/airBag95.html

The air bag diagnostic monitor measures the voltage at Pin 14 of the air bag diagnostic monitor connector. Voltage at Pin 14 should be equal to battery voltage. If the voltage at Pin 14 drops to less than 8 volts, the air bag diagnostic monitor will flash out on the air bag indicator a DTC 12. If the voltage at Pin 14 drops to less than 5 volts, the DTC 12 will also be stored in memory. Should the loss of battery voltage at Pin 14 be intermittent or repaired, the air bag diagnostic monitor will flash out a DTC 52 (or higher priority code if one exists) on the next ignition switch cycle.

Low voltage at air bag diagnostic monitor Pin 14 can be caused by:
  • An open in the battery circuit that would prevent battery voltage from reaching air bag diagnostic monitor Pin 14.
  • A short to ground on the battery feed circuit between the fuse and Pin 13 or Pin 14 of the air bag diagnostic monitor.
  • A concern in the charging system causing battery voltage to drop below 8 volts.

Unplugging the module probably won't hurt anything though according to the above, you'd be best off probing for voltage at the appropriate pins to see exactly what's going on. If your battery is almost dead, stop turning it over until you charge it or you'll have to keep investing in fuses.
 

GLRSR1951

New Member
Jul 22, 2018
2
0
1
68
Louisiana
Refer to this to troubleshoot your problem. http://www.veryuseful.com/mustang/tech/airBag/airBag95.html

The air bag diagnostic monitor measures the voltage at Pin 14 of the air bag diagnostic monitor connector. Voltage at Pin 14 should be equal to battery voltage. If the voltage at Pin 14 drops to less than 8 volts, the air bag diagnostic monitor will flash out on the air bag indicator a DTC 12. If the voltage at Pin 14 drops to less than 5 volts, the DTC 12 will also be stored in memory. Should the loss of battery voltage at Pin 14 be intermittent or repaired, the air bag diagnostic monitor will flash out a DTC 52 (or higher priority code if one exists) on the next ignition switch cycle.

Low voltage at air bag diagnostic monitor Pin 14 can be caused by:
  • An open in the battery circuit that would prevent battery voltage from reaching air bag diagnostic monitor Pin 14.
  • A short to ground on the battery feed circuit between the fuse and Pin 13 or Pin 14 of the air bag diagnostic monitor.
  • A concern in the charging system causing battery voltage to drop below 8 volts.

Unplugging the module probably won't hurt anything though according to the above, you'd be best off probing for voltage at the appropriate pins to see exactly what's going on. If your battery is almost dead, stop turning it over until you charge it or you'll have to keep investing in fuses.
OK. Thanks for the input. Much appreciated.
 

Mstng93SSP

You have a nice rear end there Dave.
15 Year Member
Nov 29, 1999
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I recently went through this on my 94 cobra. I replaced the airbag module, then went through the process of clearing the codes and have had no further issues.
 
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