AIR BAG Indicator Always On

AIR BAG INDICATOR ALWAYS ON

CIRCUIT DESCRIPTION
The ignition switch supplies battery voltage to the AIR BAG indicator using the instrument panel fuse. The AIR BAG indicator is controlled by the sensing and diagnostic module (SDM) via UART data. When the ignition switch is first turned to the ON position, the SDM responds by illuminating the AIR BAG indicator for approximately six seconds while performing diagnostic tests on the SIR system.

DIAGNOSTIC AIDS
Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.

The following are possible causes of the malfunction:
- A open or high resistance in serial data line
- A misconstrued instrument cluster
- Battery voltage below 8 volts or above 21.2 volts
- Seat belt pretensioners have deployed
- SDM has deployed
- SDM does not receive a poll from the body control module (BCM)
- An open or high resistance in the SDM ground circuit
- A open high resistance or short to ground in the SDM ignition voltage circuit
- An internal SDM malfunction
- An internal BCM malfunction

If an intermittent malfunction exists, refer to Testing for Intermittent and Poor Connections in Diagrams.

TEST DESCRIPTION

Step 1 - 5:

Step 6 - 15:

Step 16 - 21:

The number below refers to the step number on the diagnostic table.
3. Tests for serial data communication between the SDM and the scan tool.
5. Tests for proper instrument panel cluster (IPC) configuration.
6. Tests for communication with other modules.
7. Tests for a deployed SDM.
8. Tests the SDM ignition voltage circuit.
9. Tests the SDM ignition voltage (after 3 seconds).
11. Tests for a battery malfunction.
12. Tests for a charging system malfunction.
13. Tests the SDM ignition voltage circuit.
15. Tests the SDM ground circuit.
16. Tests the SDM serial data line to the IPC.