Retrieving Lamp Flash Codes (LFC)
PURPOSEPerforming system diagnostics is the main purpose of the air bag diagnostic monitor.
The air bag diagnostic monitor continually monitors all air bag system components and wiring connections for possible faults when the ignition switch is in RUN position.
OPERATION
It does not deploy the air bags in the event of a collision. The air bag diagnostic monitor operates in the following manner:
- If the air bag diagnostic monitor detects a fault in the air bag system, a Diagnostic Trouble Code (DTC) will be written to the air bag diagnostic monitor's Non-Volatile Random Access Memory (NVRAM).
- This DTC will then be displayed on the air bag indicator lamp.
- After servicing, the DTC may then be cleared from NVRAM.
- The air bag diagnostic monitor illuminates the air bag indicator for approximately six seconds when the ignition switch is turned to the RUN position and then turns the air bag indicator Off. This indicates that the air bag indicator is operational. If the air bag indicator does not illuminate at all, stays On continuously or flashes at any time, then a fault has been detected by the air bag diagnostic monitor.
- Diagnostic trouble codes, if present, will cause the AIR BAG indicator to begin flashing within 30 seconds after the ignition switch has been turned to the RUN position. This is the amount of time it takes the air bag diagnostic monitor to perform all tests and verify system faults, if present.
For example, a diagnostic trouble code 32 is displayed as three flashes, followed by a one second pause, then two flashes, followed by a three second pause. This sequence will repeat as long as the ignition switch is in the On position and the fault exists.
- Diagnostic trouble codes are retrieved using the Rotunda New Generation Star (NGS) tester 007-00500 or equivalent.
- The air bag diagnostic monitor incorporates Nonvolatile Random Access Memory (NVRAM) to store DTCs and retain them indefinitely. Diagnostic trouble codes may be cleared from the air bag diagnostic monitor after the fault conditions are serviced.
- If a system fault exists and the AIR BAG indicator is not functioning, an audible tone will be heard indicating a need for service. The tone is a series of five sets of five beeps. This does not indicate a diagnostic trouble code. The AIR BAG indicator must be serviced before diagnostic trouble codes can be determined.