Test Notes

Normal Operation
The normal voltage on Pins 2, 6, 17, and 18 is controlled by an internal resistor inside the air bag diagnostic monitor and is internally regulated to 10 volts ± 1 volt. The resistance between these pins in the air bag diagnostic monitor harness connector and ground should be infinite. The resistance across the normally open contacts of the two front air bag sensors should also be infinite. The air bag diagnostic monitor measures the voltage on Pins 2, 6, 17, and 18. If there is any resistance to ground on any of these pins or across the front air bag sensor contacts, it will cause the diagnostic voltage on these pins to drop below normal levels. If the air bag diagnostic monitor measures that this voltage has dropped to between 5 and 10 volts, the air bag diagnostic monitor senses it has an internal voltage regulation failure and will flash code 53. Note that a direct short to ground in the front air bag sensor circuits will drop the voltage to less than 5 volts and the air bag diagnostic monitor will flash code 14 on the air bag warning indicator (refer to Diagnostic Trouble Code 14).

The air bag diagnostic monitor also performs several on-board diagnostics every time the ignition switch is turned to ON. If any of these tests fail, the air bag diagnostic monitor will flash code 53 on the air bag warning indicator.


Possible Causes
A voltage drop in the front air bag sensor circuits or an internal air bag diagnostic monitor failure can be caused by:
1. A partial drop in voltage in the front air bag sensor circuits due to resistance to ground on the front air bag sensor wiring or any resistance across the normally open front air bag sensor contacts.
2. Internal air bag diagnostic monitor on-board diagnostic failure.