GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1999 🢒 Tracker - 2WD 🢒 Restraints 🢒 SIR 🢒 AIR BAG Warning Lamp Comes On Steady

Object Number: 487024 Size: MF
SIR Component Views
SIR Schematics
SIR Handling Caution
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The ignition switch supplies Ignition 1 voltage to the inflatable restraint sensing and diagnostic module (SDM) at terminal A1 using the AIR BAG fuse. The ignition switch also supplies Ignition 1 voltage to the AIR BAG warning indicator using the IG fuse. The AIR BAG warning indicator is connected to the AIR BAG indicator control terminal A9 of the SDM. When the ignition switch is first turned to the ON position, the SDM responds by flashing the AIR BAG warning indicator seven times. If Ignition 1 is outside of the normal operating voltage range (9.0 volts-16.0 volts) for more than 25 ms, the AIR BAG warning indicator will come ON solid with no DTCs set.

Diagnostic Aids

In order to disable the shorting bar from terminal A9 to terminal A18 inside the inflatable restraint sensing and diagnostic module (SDM) wiring harness connector, the following two conditions must be met:

    • The SDM wiring harness connector must be properly connected to the SDM.
    • The connector position assurance (CPA) must be properly installed in the SDM wiring 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 Intermittent Conditions and Poor Connections 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.

Test Description

The numbers below refer to the step numbers on the diagnostic table:

  1. This step checks to see if the scan tool can communicate with the inflatable restraint sensing and diagnostic module (SDM).

    2.

  2. This step checks to see if sufficient igntion voltage is applied to the SDM.

    3.

  3. This step checks to see if excessive ignition voltage is applied to the SDM.

    4.

  4. This step checks to see if the retainer assembly or the shorting bar is damaged or corroded.

    5.

  5. This step checks to see if the SDM wiring harness connector terminals are damaged or corroded.

    6.

  6. This step checks to see if the SDM terminals are damaged or corroded or if the lifting tab on the SDM is damaged.

    7.

  7. This step checks to see if the SDM wiring harness connector properly connects to the SDM and if the connector position assurance (CPA) is properly installed.

    8.

  8. This step checks to see if there is a short to ground in the AIR BAG warning indicator control circuit.

    9.

  9. This step determines if there is a short between the AIR BAG warning indicator control circuit and the SDM ground circuit or if there is a short to ground in the AIR BAG warning indicator control circuit.

    10.

  10. This step checks to see if the AIR BAG fuse is not open. An open SIR Fuse would cause the AIR BAG warning indicator to come ON steady.

    11.

  11. This step checks to see if a short to ground caused the AIR BAG fuse to open.

    12.

  12. This step checks for a short to ground in AIR BAG fuse feed circuit.

    13.

  13. This step checks to see if the SDM wiring harness connector properly secures to the SDM.

    14.

  14. This step checks to see if there is an open in AIR BAG fuse feed circuit.

    15.

  15. This step determines if there is an open or a high resistance condition in the B+ feed circuit to the input side of the AIR BAG fuse or if there is a malfunctioning SDM.

AIR BAG Warning Lamp Comes On Steady

Step

Action

Value(s)

Yes

No

1

Was the SIR Diagnostic System Check performed?

--

Go to Step 2

Go to SIR Diagnostic System Check

2

  1. Turn the ignition switch to the OFF position.
  2. Install the scan tool.
  3. Turn the ignition switch to the ON position.
  4. Use the scan tool to establish communication with the inflatable restraint sensing and diagnostic module (SDM).

Does the scan tool communicate with the SDM?

--

Go to Step 3

Go to Scan Tool Does Not Communicate with SDM

3

Use the scan tool to request the SIR scan tool data display.

Is the ignition voltage more than the specified value?

9.0 V

Go to Step 4

Go to Step 18

4

  1. Set the parking brake.
  2. Use the scan tool to request the SIR scan tool data display.

Is the ignition voltage more than the specified value?

16.0 V

Go to Battery Is Undercharged or Overcharged in Engine Electrical

Go to Step 5

5

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the SDM wiring harness connector. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  3. Use a small flat head screwdriver to remove the retainer assembly from the SDM wiring harness connector by gently lifting the locking tabs on the ends of the retainer assembly.
  4. Carefully inspect the retainer assembly and shorting bar.

Is the retainer assembly or the shorting bar damaged or corroded?

--

Go to Step 6

Go to Step 7

6
  1. Replace the retainer assembly.
  2. Follow the instructions in the GM P/N 12167318 for installation of the new retainer assembly.

Is the repair complete?

--

Go to Step 32

--

7

Carefully inspect the SDM wiring harness connector for corrosion or damaged terminals.

Are the SDM wiring harness connector terminals damaged or corroded?

--

Go to Step 8

Go to Step 9

8

Replace the damaged or corroded SDM wiring harness connector terminals. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 32

--

9

  1. Follow the instructions in the GM P/N 12167318 to properly reinstall the retainer assembly to the SDM wiring harness connector.

    2. Important: Properly inspect the SDM terminals and the shorting bar lifting tab in order to avoid misdiagnosis.

  2. Carefully inspect the SDM terminals for corrosion or damaged terminals.
  3. Also, carefully inspect the shorting bar lifting tab to ensure that it is not damaged.

Are the SDM terminals damaged or corroded or is the shorting bar lifting tab damaged?

--

Go to Step 28

Go to Step 10

10

  1. Connect the SDM wiring harness connector to the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  2. Install the connector position assurance (CPA).

Does the SDM wiring harness connector properly connect to the SDM and is the CPA properly installed?

--

Go to Step 12

Go to Step 11

11

Replace the SDM wiring harness connector. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 32

--

12
  1. Disconnect the inflatable restraint IP module yellow 2-way connector and the inflatable restraint steering wheel module yellow 2-way connector.
  2. Disconnect the SDM wiring harness connector. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  3. Install the J 42113 SIR Shorting Bar Tool into the SDM wiring harness connector above terminal A9 and terminal A18.
  4. Install the CPA.
  5. Turn the ignition switch to the ON position.

Does the air bag warning indicator come ON steady?

--

Go to Step 13

Go to Step 28

13

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.
  3. Use the J 39200 Digital Multimeter (DMM) to measure the resistance between terminal A9 of the SDM wiring harness connector and a known good ground.

Is the measured resistance less than the specified value?

OL

Go to Step 14

Go to Step 17

14

  1. Disconnect the SDM ground circuit from G202.
  2. Use the J 39200 to measure the resistance between terminal A9 and terminal A18 of the SDM wiring harness connector.

Is the resistance reading less than the specified value?

OL

Go to Step 16

Go to Step 15

15

Locate and repair a short to ground in the AIR BAG indicator control circuit. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 32

--

16
  1. Locate and repair a short between the AIR BAG indicator control circuit and the SDM ground circuit.
  2. Inspect the SDM ground circuit for any cutting or chafing.

Is the repair complete?

--

Go to Step 32

--

17

Replace the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.

Is the repair complete?

--

Go to Step 32

--

18

  1. Turn the ignition switch to the OFF position.
  2. Remove the AIR BAG fuse.
  3. Inspect the AIR BAG fuse.

Is the AIR BAG fuse open?

--

Go to Step 19

Go to Step 23

19

  1. Replace the AIR BAG fuse.
  2. Turn the ignition switch to the ON position for 10 seconds.
  3. Turn the ignition switch to the OFF position.
  4. Remove the AIR BAG fuse.
  5. Inspect the AIR BAG fuse.

Is the AIR BAG fuse open?

--

Go to Step 20

Go to Step 22

20

  1. Disconnect the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  2. Use the J 39200 to measure the resistance between the output side of the AIR BAG fuse and a known good ground.

Is the measured resistance less than the specified value?

OL

Go to Step 21

Go to Step 28

21
  1. Locate and repair a short to ground in the ignition voltage feed circuit to the SDM. Refer to Wiring Repairs in Wiring Systems.
  2. Replace the AIR BAG fuse.

Is the repair complete?

--

Go to Step 32

--

22

Install the AIR BAG fuse.

Is the repair complete?

--

Go to Step 32

--

23

Inspect the SDM wiring harness connector. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .

Is the connector secure?

--

Go to Step 25

Go to Step 24

24
  1. Properly connect the SDM wiring harness connector to the SDM.
  2. Install the CPA.

Is the repair complete?

--

Go to Step 32

--

25
  1. Disconnect the inflatable restraint IP module yellow 2-way connector and the inflatable restraint steering wheel module yellow 2-way connector.
  2. Disconnect the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  3. Check the SDM wiring harness connector for a proper connection at terminal A1.

Is the SDM wiring harness connector terminal A1 damaged or corroded?

--

Go to Step 26

Go to Step 27

26

Replace the SDM wiring harness connector. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 32

--

27

Inspect the SDM terminals for damage or corrosion.

Are any terminals damaged or corroded?

--

Go to Step 28

Go to Step 29

28

Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .

Is the repair complete?

--

Go to Step 32

--

29

Use the J 39200 to measure the resistance between the output side of the AIR BAG fuse and terminal A1 of the SDM wiring harness connector.

Is the measured resistance within the specified value?

0-2 ohms

Go to Step 31

Go to Step 30

30

Locate and repair an open or a high resistance condition in the ignition voltage feed circuit to the SDM. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 32

--

31

  1. Turn the ignition switch to the ON position.
  2. Use the J 39200 to measure the voltage between the input side of the AIR BAG fuse and a known good ground.

Is the measured voltage within the specified value?

B+

Go to Step 28

Go to Power Distribution Schematics in Wiring Systems

32
  1. Reconnect all SIR components.
  2. Make sure that all components and connectors are properly mounted.

Have all the SIR components been reconnected and properly mounted?

--

Go to SIR Diagnostic System Check

--