Test Notes

NOTE: The air bag connector, air bag diagnostic monitor harness connector, and the air bag sliding contact connector have metal spring clips that act as shorting bars. These shorting bars are built into the plastic hard-shell connectors. The shorting bars are designed to short Circuit 614 (GY/O) and 615 (GY/W) 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. Likewise, the shorting bar(s) in the air bag diagnostic monitor harness connector may be removed by removing the black spacer (locking wedge) from the connector. Use extreme caution when reinstalling the shorting bars to ensure they are installed correctly.

NORMAL OPERATION
Diagnostic Trouble Code 74 refer to Diagnostic Trouble Code 34While the ignition switch is in the RUN position, the air bag diagnostic monitor runs periodic checks on the resistance of the driver and passenger air bag circuits. Normal resistance from Pin 2 (Driver Air Bag Feed) to Pin 3 (Driver Air Bag Return) is between 1.4 ohms and 2.0 ohms.

- This resistance total results from the sum of the components in the circuit: the air bag (approximately 1 ohm) and the air bag sliding contact (0.20 ohm to 0.35 ohm per winding, 2 windings total) plus a small amount of resistance due to the wire itself, crimps, etc..

- If the resistance across these two pins is less than 1 ohm, the air bag diagnostic monitor will interpret this as a low resistance and the air bag diagnostic monitor will store in memory and flash out on the air bag indicator a DTC 34.

- If the low resistance is later serviced or otherwise rises into the normal range, the next ignition switch cycle will produce a DTC 74 (or a higher priority DTC if one exists).

POSSIBLE CAUSES

Low Resistance Across Pins 2 and 3 Can Be Caused By:

- A poorly mated air bag connector, air bag diagnostic monitor harness connector, or air bag sliding contact connector may not push the shorting bars back into their fully retracted position.

- A damaged or worn shorting bar may short Circuits 614 (GY/O) and 615 (GY/W).

- A short in the air bag sliding contact windings or harness wires between Circuits 614 (GY/O) and 615 (GY/W).

- A short circuit or low resistance in the driver side air bag module. DO NOT attempt a direct resistance measurement of the air bag. Follow the diagnostic procedure to determine if the air bag resistance is higher than normal.