When the ignition switch is first turned to RUN, the GAUGES Fuse applies battery voltage to the AIR BAG warning lamp that is connected to Air Bag Indicator Control, terminal 7. The AIR BAG Fuse applies battery voltage to the IGNITION 1 input, terminal 10. The inflatable restraint sensing and diagnostic module (SDM) responds by flashing the AIR BAG warning lamp seven times. If IGNITION 1 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 Digital Multimeter with the correct terminal adapter from the J 35616-A Connector Test Adapter Kit. When an inspection for proper connection is requested, refer to Intermittents and Poor Connections in Restraints, 1999 C/K Service Manual. When a wire, connector or terminal repair is requested, use the J 38125-B Terminal Repair Kit. Refer to Wiring Repair in Restraints, 1999 C/K Service Manual.
The numbers below refer to the step numbers on the diagnostic table:
This test checks for sufficient IGNITION 1 voltage applied to the SDM.
This test checks for excessive IGNITION 1 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 1 circuit.
Step | Action | Value(s) | Yes | No |
---|---|---|---|---|
1 | Was the SIR Diagnostic System Check performed? | -- | Go to Step 2 | Go to SIR Diagnostic System Check in Restraints, 1999 C/K Service Manual |
Is IGNITION more than the specified value? | 8.2 V | Go to Step 3 | Go to Step 20 | |
Is IGNITION more than the specified value? | 17.1 V | Go to Charging System Check in Engine Electrical, 1999 C/K Service Manual | Go to Step 4 | |
Is the CPA properly installed? | -- | Go to Step 6 | Go to Step 5 | |
5 | Properly install the CPA. Are the repairs complete? | -- | Go to SIR Diagnostic System Check in Restraints, 1999 C/K Service Manual | -- |
Does the AIR BAG warning lamp come ON steady? | -- | Go to Step 7 | Go to SDM Integrity Check in Restraints, 1999 C/K Service Manual | |
Is the shorting bar damaged or corroded? | -- | Go to Step 8 | Go to Step 9 | |
8 | Replace the SDM harness connector. Refer to Connector Repairs in Wiring Systems, 1999 C/K Service Manual. Are the repairs complete? | -- | Go to Step 34 | -- |
9 |
Is the shorting bar damaged or corroded? | -- | Go to Step 10 | Go to Step 11 |
10 | Replace the IP harness side of connector C232. Refer to Connector Repairs in Wiring Systems, 1999 C/K Service Manual. Has the IP harness side of connector C232 been replaced? | -- | Go to Step 11 | -- |
11 | Check for proper connection at terminal A1 and A2 on the IP harness side of connector C232. Are the terminals damaged or corroded? | -- | Go to Step 12 | Go to Step 13 |
12 | Replace the IP harness side of connector C232. Refer to Connector Repairs in Wiring Systems, 1999 C/K Service Manual. Has the IP harness side of connector been replaced? | -- | Go to Step 13 | -- |
13 | Check for proper connection at terminals A1 and A2 on the harness side of connector C232. Are the terminals damaged or corroded? | -- | Go to Step 14 | Go to Step 15 |
14 | Replace the harness side of connector C232. Refer to Connector Repairs in Wiring Systems, 1999 C/K Service Manual. Has the harness side of connector C232 been replaced? | -- | Go to Step 33 | -- |
Is the resistance reading less than the specified value? | OL | Go to Step 16 | Go to Step 19 | |
Is the resistance reading less than the specified value? | OL | Go to Step 18 | Go to Step 17 | |
17 | Repair a short to ground condition in CKT 358. Are the repairs complete? | -- | Go to Step 34 | -- |
18 |
Are the repairs complete? | -- | Go to Step 34 | -- |
19 | Service the instrument cluster and repair as necessary. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges And Console. Was a repair necessary? | -- | Go to Step 34 | Go to Step 20 |
Is the Air Bag Fuse good? | -- | Go to Step 26 | Go to Step 21 | |
Is the Air Bag Fuse good? | -- | Go to Step 25 | Go to Step 22 | |
Is the Air Bag Fuse good? | -- | Go to Step 24 | ||
23 |
Are the repairs complete? | -- | Go to Step 34 | -- |
24 |
Are the repairs complete? | -- | Go to Step 34 | -- |
25 | Install the Air Bag Fuse. Are the repairs complete? | -- | Go to Step 34 | -- |
Inspect the SDM harness connector. Is the connector securely connected to the SDM? | -- | Go to Step 28 | Go to Step 27 | |
27 |
Are the repairs complete? | -- | Go to Step 34 | -- |
28 |
Is the SDM harness connector terminal damaged or corroded? | -- | Go to Step 29 | Go to Step 30 |
29 | Replace the SDM harness connector. Refer to Connector Repairs in Wiring Systems, 1999 C/K Service Manual. Are the repairs complete? | -- | Go to Step 34 | -- |
30 | Inspect the SDM terminals for damage or corrosion. Are any terminals damaged or corroded? | -- | Go to Step 31 | Go to Step 32 |
31 | Replace the SDM. Refer to Infl Rst Sensing and Diagnostic Module Replacement in Restraints, 1999 C/K Service Manual. Are the repairs complete? | -- | Go to Step 27 | -- |
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 | Go to SDM Integrity Check in Restraints, 1999 C/K Service Manual | Go to Step 33 | |
33 | Repair an open condition in CKT 1139. Are the repairs complete? | -- | Go to Step 34 | -- |
34 | Reconnect all the SIR system components, make sure all the components are properly mounted. Have all the SIR components been reconnected and properly mounted? | -- | Go to SIR Diagnostic System Check in Restraints, 1999 C/K Service Manual | -- |