Circuit Description
When the ignition switch is turned to ON, the sensing and diagnostic module (SDM) will perform a turn-on test to diagnose critical malfunctions within the SDM itself.
Upon passing this test, ignition and deployment loop voltages are measured to ensure that they are within their normal voltage ranges. The SDM monitors the voltages at the driver low and the passenger low to detect shorts to ground or voltage in the deploy loops.
The SDM inspects the wiring connection to the passenger air bag module by letting the infinitesimal current flow through the internal circuit and verify the resistance. If the warning lamp operates properly ON and OFF, the SDM checks the voltage continuously from the warning lamp terminal.
Conditions for Setting the DTC
The warning lamp does not properly blink ON and OFF.
Diagnostic Aids
When the ignition switch is turned ON, normally, the warning lamp blinks 7 times during 7 seconds.
If the warning lamp stays ON or blinks a second after the normal blinking, 7 times during 7 seconds, it is regarded as a defect, old or current. Inspect the defect with a scan tool.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
|
Caution: Refer to Sensing and Diagnostic Module Voltage after Ignition is Turned Off Caution in the Preface section. Caution: Refer to Sensing and Diagnostic Module Handling Caution in the Preface section. | ||||
1 | Did you perform the Diagnostic System Check - SIR? | -- | Go to Step 2 | |
2 |
Is there any visible damage to the SIR wiring harness? | -- | Go to Step 4 | Go to Step 3 |
3 | Check the resistance between the SDM and the high, low wiring of driver side air bag module and the ground. Is the resistance as specified? | 10k ohms | Go to Step 6 | Go to Step 5 |
4 | Replace the SIR wiring harness. Did you complete the repair? | -- | -- | |
5 | Repair the power supply to the fuse F4. Did you complete the repair? | -- | -- | |
6 |
Is the bulb OK? | -- | Go to Step 8 | Go to Step 7 |
7 | Replace the bulb of air bag warning lamp. Did you complete the repair? | -- | System OK | -- |
8 |
Is the voltage as specified? | 11-14 V | Go to Step 10 | Go to Step 9 |
9 | Repair the wire between the fuse F12 and the terminal B14 of cluster connector. Did you complete the repair? | -- | -- | |
10 | Check the connection between terminal B14 and B16 from the cluster. Is the connection OK? | -- | Go to Step 12 | Go to Step 11 |
11 | Replace the instrument cluster. Did you complete the repair? | ∞ | -- | |
12 |
Is the voltage as specified? | 11-14 V | Go to Step 13 | Go to Step 14 |
13 | Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Did you complete the repair? | -- | -- | |
14 | Repair the wiring between the terminal 7 of the SDM and the instrument cluster. Did you complete the repair? | -- | -- | |
