When the ignition switch is first turned to the RUN position, the CHIME Fuse (Buick UB3) or PCM Fuse (All others) applies battery voltage to the AIR BAG warning lamp that is connected to SIR INDICATOR, terminal 7. The AIR BAG Fuse applies battery voltage to the IGNITION POSITIVE VOLTAGE input, terminal 10. The inflatable restraint Sensing and Diagnostic Module (SDM) responds by flashing the AIR BAG warning lamp seven times. If IGNITION POSITIVE VOLTAGE is outside of the normal operating voltage range (8.2 volts - 17.1 volts), the AIR BAG warning lamp will come ON solid with no DTCs set.
In order to disable the shorting bar from terminal 6 to terminal 7 inside the inflatable restraint Sensing and Diagnostic Module (SDM) harness connector, the following two conditions must be met:
• | The SDM harness connector must be properly connected to the SDM. |
• | The Connector Position Assurance (CPA) must be properly installed in the SDM harness connector. |
When measurements are requested in this table, use the J 39200 DMM with the correct terminal adapter from the J 35616 Connector Test Adapter Kit. When an inspection for proper connection is requested, refer to Testing for Electrical Intermittents in Wiring Systems. When a wire, connector or terminal repair is requested, use the J-38125 Terminal Repair Kit and refer to Wiring Repairs in Wiring Systems.
The numbers below refer to the step numbers on the diagnostic table:
This test checks for sufficient IGNITION POSITIVE VOLTAGE voltage applied to the SDM.
This test checks for excessive IGNITION POSITIVE VOLTAGE voltage applied to the SDM.
This test checks for a properly installed CPA.
This test determines if the SDM is turning on the AIR BAG warning lamp.
This test checks for a damaged shorting bar.
This test determines whether the malfunction is a short-to-ground in CKT 358.
This test checks for a short between CKTs 358 and 1751.
An open AIR BAG Fuse would cause the AIR BAG warning lamp to come on steady.
This test checks whether a short-to-ground caused the AIR BAG Fuse to open.
This test determines whether the short-to-ground is due to a short in the wiring or internal to the SDM.
This test checks for a disconnected SDM.
This test checks for an open in the IGNITION POSITIVE VOLTAGE circuit.
Step | Action | Value(s) | Yes | No |
---|---|---|---|---|
1 | Was the SIR Diagnostic System Check performed? | -- | ||
Is IGNITION more than the specified value? | 8.2 V | |||
Is IGNITION more than the specified value? | 17.1 V | Go to Charging System Check | ||
Is the CPA properly installed? | -- | |||
5 | Properly install the CPA. Are the repairs complete? | -- | -- | |
Does the AIR BAG warning lamp come ON steady? | -- | |||
Is the shorting bar damaged or corroded? | -- | |||
8 | Replace the SDM harness connector. Are the repairs complete? | -- | -- | |
Is the resistance reading less than the specified value? | OL | |||
Is the resistance reading less than the specified value? | OL | |||
11 | Repair a short-to-ground condition in CKT 358. Are the repairs complete? | -- | -- | |
12 |
Are the repairs complete? | -- | -- | |
13 | Service the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges, and Console. Are the repairs complete? | -- | -- | |
Is the AIR BAG Fuse good? | -- | |||
Is the AIR BAG Fuse good? | -- | |||
Is the AIR BAG Fuse good? | -- | |||
17 |
Are the repairs complete? | -- | -- | |
18 |
Are the repairs complete? | -- | -- | |
19 | Install the AIR BAG Fuse. Are the repairs complete? | -- | -- | |
Inspect the SDM harness connector. Is the connector secure? | -- | |||
21 |
Are the repairs complete? | -- | -- | |
22 |
Is the SDM harness connector terminal damaged or corroded? | -- | ||
23 | Replace the SDM harness connector. Refer to Wiring Repair . Are the repairs complete? | -- | -- | |
24 | Inspect the SDM terminals for damage or corrosion. Are any terminals damaged or corroded? | -- | ||
25 | Replace the inflatable restraint Sensing and Diagnostic Module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Are the repairs complete? | -- | -- | |
Measure the resistance from the SDM harness connector terminal 10 to each terminal of the AIR BAG Fuse fuseholder. Is either resistance reading within the specified values? | 0-5 ohms | |||
27 | Repair an open condition in CKT 1139. Are the repairs complete? | -- | -- | |
28 | Reconnect all the SIR system components, make sure all the components are properly mounted. Have all the SIR components been reconnected and properly mounted? | -- | -- |