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For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 1999 🢒 Montana 🢒 Restraints 🢒 SIR 🢒 AIR BAG Warning Lamp Comes On Steady

Object Number: 417321 Size: SF
SIR Components
SIR Schematics
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice
SIR Caution

Circuit Description

When the ignition switch is first turned to the RUN position, the IGN 1 Fuse applies battery voltage to the AIR BAG warning lamp that is connected to the INFLATABLE RESTRAINT INDICATOR, terminal 6. The SIR Fuse applies battery voltage to the IGNITION input, terminal 5. The inflatable restraint sensing and diagnostic module (SDM) responds by flashing the AIR BAG warning lamp seven times. If IGNITION is outside of the normal operating voltage range (9 volts - 16 volts), the AIR BAG warning lamp will come ON solid with no DTCs set.

Diagnostic Aids

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 SDM harness connector must be properly connected to the SDM.

When measurements are requested in this table, use J 39200 Digital Multimeter with the correct terminal adapter from J 35616 Connector Test Adapter Kit. When a check for proper connection is requested, refer to Intermittents and Poor Connections . When a wire, connector or terminal repair is requested, use J-38125 Terminal Repair Kit and refer to Wiring Repair .

Test Description

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

  1. This step checks to see if sufficient IGNITION voltage applied to the SDM.

    2.

  2. This step checks to see if IGNITION voltage applied to the SDM.

    3.

  3. This step checks to see if the connector position assurance (CPA) is properly installed.

    4.

  4. This step determines if the SDM is turning ON the AIR BAG warning lamp or if there is a malfunctioning SDM.

    5.

  5. This step checks to see if the shorting bar is damaged.

    6.

  6. This step checks to see if there is a short to ground CKT 358.

    7.

  7. This step checks to see if there is a short between CKT 358 and CKT 1751 or if there is a short to ground in CKT 358.

    8.

  8. This step checks to see if the SIR Fuse is open. An open SIR Fuse would cause the AIR BAG warning lamp to come on steady.

    9.

  9. This step checks to see if the short to ground caused the SIR Fuse to open.

    10.

  10. This step checks for a short to ground in CKT 1751.

    11.

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

    12.

  12. This step checks to see if there is an open in CKT 1139.

    13.

  13. This step determines if there is an open or a high resistance in the B+ feed circuit to the input side of the SIR 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 RUN position.
  4. Use the scan tool to request the SIR data list display.

Is the ignition voltage more than the specified value?

9 V

Go to Step 3

Go to Step 14

3

  1. Set the parking brake.
  2. Start the engine.
  3. Use the scan tool to request the SIR data list display.

Is the ignition voltage more than the specified value?

16 V

Go to Battery Is Undercharged or Overcharged in Engine Electrical

Go to Step 4

4

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the inflatable restraint sensing and diagnostic module. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  3. Inspect the SDM wiring harness connector position assurance (CPA).

Is the SDM CPA properly installed?

--

Go to Step 6

Go to Step 5

5

Properly install the CPA.

Is the repair complete?

--

Go to Step 28

--

6

  1. Disconnect the inflatable restraint steering wheel module coil and inflatable restraint IP module yellow 2-way connectors.
  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 6 and terminal 7.
  4. Turn the ignition switch to the RUN position.

Does the AIR BAG warning lamp come ON steady?

--

Go to Step 7

Go to Sensing and Diagnostic Module Integrity Check

7

  1. Turn the ignition switch to the OFF position.
  2. Remove the J 42113 SIR Shorting Bar Tool from the SDM wiring harness connector.
  3. Inspect the shorting bar across terminal 6 and terminal 7 within the SDM wiring harness connector.

Is the shorting bar damaged or corroded?

--

Go to Step 8

Go to Step 9

8

Replace the SDM wiring harness connector. Refer to Wiring Repair .

Is the repair complete?

--

Go to Step 28

--

9

  1. Insert the J 42113 SIR Shorting Bar Tool into the SDM wiring harness connector above terminal 6 and terminal 7.
  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 6 of the SDM wiring harness connector and a known good ground.

Is the measured resistance less than the specified value?

OL

Go to Step 10

Go to Step 13

10

  1. Disconnect CKT 1751 from G302. Refer to SIR Components .
  2. Use the J 39200 to measure the resistance between terminal 6 and terminal 7 of the SDM wiring harness connector.

Is the measured resistance less than the specified value?

OL

Go to Step 12

Go to Step 11

11
  1. Locate a short to ground in CKT 358.
  2. Repair the short to ground in CKT 358.

Is the repair complete?

--

Go to Step 28

--

12
  1. Locate a short between CKT 358 and CKT 1751.
  2. Repair the short between CKT 358 and CKT 1751.
  3. Inspect CKT 1751 for cutting or chafing.

Is the repair complete?

--

Go to Step 28

--

13

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

Is the repair complete?

--

Go to Step 28

--

14

  1. Turn the ignition switch to the OFF position.
  2. Remove the SIR Fuse.
  3. Inspect the SIR Fuse.

Is the SIR Fuse good?

--

Go to Step 21

Go to Step 15

15

  1. Replace the SIR Fuse.
  2. Turn the ignition switch to the RUN position for 10 seconds.
  3. Turn the ignition switch to the OFF position.
  4. Remove the SIR Fuse.
  5. Inspect the SIR Fuse.

Is the SIR Fuse good?

--

Go to Step 18

Go to Step 16

16

  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 SIR Fuse and a known good ground.

Is the measured resistance less than the specified value?

OL

Go to Step 17

Go to Step 24

17
  1. Locate a short to ground in CKT 1139.
  2. Repair the short to ground in CKT 1139.
  3. Replace the SIR Fuse.

Is the repair complete?

--

Go to Step 28

--

18

Install the SIR Fuse.

Is the repair complete?

--

Go to Step 28

--

19

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

Is the connector secure?

--

Go to Step 21

Go to Step 20

20
  1. Properly connect the SDM wiring harness connector.
  2. Install the CPA.

Is the repair complete?

--

Go to Step 28

--

21
  1. Disconnect the inflatable restraint steering wheel module coil and IP module yellow 2-way connectors.
  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 5.

Is the SDM wiring harness connector terminal 5 damaged or corroded?

--

Go to Step 22

Go to Step 23

22

Replace the SDM wiring harness connector. Refer to Wiring Repair .

Is the repair complete?

--

Go to Step 28

--

23

Inspect the SDM terminals for damage or corrosion.

Are any terminals damaged or corroded?

--

Go to Step 24

Go to Step 25

24

Replace the inflatable restraint sensing and diagnostic module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement

Is the repair complete?

--

Go to Step 28

--

25

Use the J 39200 to measure the resistance between the output side of the SIR Fuse and terminal 5 of the SDM wiring harness connector.

Is the measured resistance within the specified value?

0-2 ohms

Go to Step 27

Go to Step 26

26
  1. Locate an open or a high resistance in CKT 1139.
  2. Repair the open or the high resistance in CKT 1139.

Is the repair complete?

--

Go to Step 28

--

27

  1. Turn the ignition switch to the RUN position.
  2. Use the J 39200 to measure the voltage between the input side of the SIR Fuse and a known good ground.

Is the measured voltage within the specified value?

B+

Go to Step 24

Go to Power Distribution Schematics in Wiring Systems

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?

--

Go to SIR Diagnostic System Check

--