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Home >> Mercury >> 1994 >> Topaz L4-140 2.3L HSC >> Repair and Diagnosis >> Restraints and Safety Systems >> Air Bag Systems >> Testing and Inspection >> Diagnostic Trouble Code Tests and Associated Procedures >> Manufacturer Code Charts >> 34: Driver Side Air Bag Circuit Low Resistance or Shorted

34: Driver Side Air Bag Circuit Low Resistance or Shorted

Electrical Schematic:





Normal Operation
The diagnostic monitor measures the resistance across Pin 10 (Circuit 615, GY/W) and Pin 11 (Circuit 614, GY/O) every time the ignition switch is turned to RUN. Normal resistance across these circuits is between 1.5 ohms and 2.0 ohms. This resistance comes from the air bag itself (approximately 1.0 ohm) and the air bag sliding contact windings (0.25 to 0.5 ohm per winding, two windings in all). If the resistance across these two circuits is less than 0.7 ohm, the diagnostic monitor will flash Diagnostic Trouble Code 34 on the air bag indicator.

NOTE: The connectors for the air bag and the air bag sliding contact have metal spring clips that act as shorting bars. These shorting bars are built into the plastic hardshell connectors. The shorting bars are designed to short Circuits 614 and 615 together when the connectors are not mated. DO NOT attempt to remove the air bag shorting bar and measure the resistance of the air bag. The air bag sliding contact shorting bar may be removed to measure the air bag sliding contact resistance. Use extreme care when reinstalling the shorting bar to ensure it is installed correctly.

Possible Causes
Low resistance across Pins 10 and 11 can be caused by:
1. A poorly mated air bag sliding contact connector may not push the shorting bar back into its fully retracted position.
2. A damaged air bag sliding contact shorting bar may short Circuits 614 and 615 together.
3. A short in the air bag sliding contact windings between Circuits 614 (GY/O) and 615 (GY/W).
4. A poorly mated air bag connector may not push the shorting bar back into its fully retracted position.
5. A damaged air bag shorting bar may short Circuits 614 (GY/O) and 615 (GY/W).
6. A short across the air bag terminals within the air bag. DO NOT attempt a direct resistance measurement of the air bag. Follow the diagnostic procedures to determine if the air bag resistance is lower than normal.

Pinpoint Test Steps:

34-1 - 34-3:





34-4:




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