my bible says that code 12 = low battery voltage. The air bag diagnostic monitor measures the voltage at pin 14 of the air bag diagnostic monitor connector. The voltage at pin 14 should be equal to battery voltage. If the voltage at pin 14 drops to less then 9 volts the air bag diagnostic monitor will store in memory and flash out on the air bag indicator a DTC 12. Should the loss of battery voltage at pin 14 be intermittent or repaired the air bag diagnostic monitor will flash out a DTC52 on the next ignition switch. Check your battery, check your connections. By check I mean remove them, clean them and then tighten them up till you can move them. You just checked your connections....