GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2001 🢒 Metro 🢒 Restraints 🢒 SIR 🢒 AIR BAG Warning Lamp Comes On Steady

Object Number: 424974 Size: MF
SIR Components
SIR Schematics
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice
SIR Handling Caution

Circuit Description

When the ignition switch is first turned to the ON position, the IG-COIL Fuse applies battery voltage to the AIR BAG warning lamp that is connected to the AIR BAG INDICATOR, terminal 7. The AIR BAG fuse applies battery voltage to the IGNITION 1 input, terminal 8. 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 to 17.1 volts), then 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 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 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 in this section.

Test Description

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

  1. This test checks for sufficient IGNITION 1 voltage applied to the SDM.

    2.

  2. This test checks for excessive IGNITION 1 voltage applied to the SDM.

    3.

  3. This test checks for a correctly installed CPA.

    4.

  4. This test determines if the SDM is turning the AIR BAG warning lamp ON.

    5.

  5. This test checks for a damaged shorting bar.

    6.

  6. This test determines whether the malfunction is a short to ground in the ORN wire.

    7.

  7. This test checks for a short between the ORN wire and the BLK wire.

    8.

  8. This test checks for an open AIR BAG Fuse. An open AIR BAG Fuse would cause the AIR BAG warning lamp to come ON steady.

    9.

  9. This test determines if a short to ground caused the AIR BAG Fuse to open.

    10.

  10. This test determines if the short to ground is due to a short in the wiring or internal to the SDM.

    11.

  11. This test checks for a disconnected SDM.

    12.

  12. This test checks for an open in the IGNITION 1 circuit.

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 LOCK position.
  2. Connect a scan tool to the data link connector. Follow the directions in the scan tool instruction manual.
  3. Turn the ignition switch to the ON position.
  4. Request the SIR data list display.

Is IGNITION higher than the specified value?

8.2 V

Go to Step 3

Go to Step 14

3

  1. Set the parking brake.
  2. Start the engine.
  3. Using the scan tool, read the SIR data list.

Is IGNITION higher than the specified value?

17.1 V

Go to Charging System Check in Engine Electrical

Go to Step 4

4

  1. Turn the ignition switch to the LOCK position.
  2. Inspect the inflatable restraint Sensing and Diagnostic Module (SDM) harness connector CPA (Connector Position Assurance).

Did you install the CPA correctly?

--

Go to Step 6

Go to Step 5

5

Install the CPA correctly in order to deactivate the shorting bar in the SDM harness connector.

Did you install the SDM harness connector CPA correctly?

--

Go to SIR Diagnostic System Check

--

6

  1. Disconnect the inflatable restraint steering wheel and the inflatable restraint IP module's yellow connectors located under the steering wheel side cap and behind the IP compartment.
  2. Disconnect the SDM.
  3. Install the J 38715-96 connector to the inflatable restraint control module harness connector.
  4. Install the CPA.

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 LOCK position.
  2. Remove the J 38715-96 connector from the SDM harness connector.
  3. Carefully inspect the shorting bar within the SDM harness connector.

Is the shorting bar damaged or corroded?

--

Go to Step 8

Go to Step 9

8

Replace the SDM harness connector. Refer to SIR connector (Plastic Body and Terminal Metal Pin) Repair portion of Wiring Repair .

Did you replace the SDM harness connector?

--

Go to Step 28

--

9

  1. Install the J 38715-96 connector to the inflatable restraint control module harness connector.
  2. Disconnect the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.
  3. Measure the resistance from the SDM harness connector terminal 7 to ground.

Is the resistance reading less than the specified value?

OL

(Infinite)

Go to Step 10

Go to Step 13

10

  1. Disconnect the BLK /WHT wire (Terminal 6) at the SIR ground near the SDM.
  2. Measure the resistance from the SDM harness connector terminal 7 to terminal 6.

Is the resistance reading less than the specified value?

OL

(Infinite)

Go to Step 12

Go to Step 11

11

Repair a short to ground condition in the ORN wire.

Is the circuit repair complete?

--

Go to Step 28

--

12

Repair the short from the ORN wire to the BLK wire.

Is the circuit repair complete?

--

Go to Step 28

--

13

Service the instrument cluster. Refer to Instrument Cluster System Check in Instrument Panel, Guages, and Console.

Is the repair complete?

--

Go to Step 28

--

14

  1. Turn the ignition switch to the LOCK position.
  2. Remove the AIR BAG Fuse. Inspect the AIR BAG Fuse.

Is the AIR BAG Fuse good?

--

Go to Step 20

Go to Step 15

15

  1. Replace the AIR BAG Fuse.
  2. Turn the ignition switch to the ON position, wait 10 seconds, then turn the ignition switch to the LOCK position.
  3. Remove the AIR BAG Fuse.
  4. Inspect the AIR BAG Fuse.

Is the AIR BAG Fuse good?

--

Go to Step 19

Go to Step 16

16

  1. Disconnect the SDM.
  2. Replace the AIR BAG Fuse.
  3. Turn the ignition switch to the ON position, wait 10 seconds, then turn the ignition switch to the LOCK position.
  4. Remove the AIR BAG Fuse.
  5. Inspect the AIR BAG Fuse.

Is the AIR BAG Fuse good?

--

Go to Step 18

Go to Step 17

17
  1. Repair a short to ground condition in the BLU/RED wire.
  2. Reconnect the SDM.
  3. Replace the AIR BAG Fuse.

Is the circuit repair complete and the AIR BAG Fuse replaced?

--

Go to Step 28

--

18
  1. Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement in this section.
  2. Install the AIR BAG Fuse.

Did you replace the SDM and install the AIR BAG Fuse?

--

Go to Step 28

--

19

Install the AIR BAG Fuse.

Did you install the AIR BAG Fuse?

--

Go to Step 28

--

20

  1. Turn the ignition switch to the LOCK position.
  2. Inspect the SDM harness connector connection to the SDM.

Is the SDM harness connector securely connected to the SDM?

--

Go to Step 22

Go to Step 21

21

Connect the SDM securely and install the CPA to deactivate the shorting bar in the SDM harness connector.

Is the SDM connected properly and the CPA installed?

--

Go to Step 28

--

22
  1. Disconnect the inflatable restraint steering wheel and the inflatable restraint IP modules' yellow connectors located under the steering wheel side cap and behind the IP compartment.
  2. Disconnect the SDM.
  3. Check for proper connection to the SDM at terminal 8.

Are the SDM harness connectors corroded?

--

Go to Step 23

Go to Step 24

23

Replace the SDM harness connector. Refer to SIR Connector (Plastic Body and Thermal Metal Pin) Repair portion of Wiring Repair in this section.

Has the SDM harness connector been replaced?

--

Go to Step 28

--

24

Carefully inspect the SDM terminals for damage or corrosion.

Are the SDM terminals damaged or corroded?

--

Go to Step 25

Go to Step 26

25

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

Did you replace the SDM?

--

Go to Step 28

--

26

Measure the resistance from the SDM harness connector terminal 8 to each terminal of the AIR BAG Fuse fuseholder.

Is either resistance reading within the specified values?

0-5 ohms

Go to Sensing and Diagnostic Module Integrity Check

Go to Step 27

27

Repair an open condition in the YEL/BLK wire.

Is the circuit repair complete?

--

Go to Step 28

--

28
  1. Reconnect all the SIR system components.
  2. Confirm that all the components are properly mounted.

Are all the SIR components connected and properly mounted?

--

Go to SIR Diagnostic System Check

--