GM Service Manual Online
For 1990-2009 cars only

Object Number: 240876  Size: SF
SIR Components
SIR Schematics
SIR Caution
SIR Caution
Handling ESD Sensitive Parts Notice

Circuit Description

When you first turn the ignition switch to the ON position, the inflatable restraint Sensing and Diagnostic Module (SDM) performs tests to diagnose critical malfunctions within itself. The SDM internally monitors the side air bag sensor, the safing sensor, the drive circuit, the diagnosis circuit and the ignition control. If a malfunction is detected, the SDM will set a DTC and illuminate the AIR BAG warning lamp.

Conditions for Setting the DTC

The SDM detects a short or open in any of the side impact sensor circuits.

The SDM detects a malfunction in the inflatable restraint side impact sensor.

Action Taken When the DTC Sets

    • The SDM sets a Diagnostic Trouble Code.
    • The SDM flashes the AIR BAG warning lamp.

Conditions for Clearing the DTC

All DTCs are cleared with each ignition cycle.

Test Description

  1. This test checks for an open or high resistance condition in the PNK wire.

  2. This test checks for an open or high resistance condition in the BLU/YEL wire.

  3. This test checks for an open or high resistance condition in the LT GRN wire.

  4. This test checks for an open or high resistance condition in the GRY wire.

  5. This test checks for a short to ground in the PNK wire.

  6. This test checks for a short to ground in the BLU/YEL wire.

  7. This test checks for a short to ground in the LT GRN wire.

  8. This test checks for a short to ground in the GRY wire.

  9. This test checks for a short to voltage in the PNK wire.

  10. This test checks for a short to voltage in the BLU/YEL wire.

  11. This test checks for a short to voltage in the LT GRN wire.

  12. This test checks for a short to voltage in the GRY wire.

  13. This test checks for a short between any of the RH side impact sensor circuits.

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. Disconnect the inflatable restraint Sensing and Diagnostic Module (SDM).
  3. Disconnect the RH side impact sensor.
  4. Zero the J 39200 .
  5. Measure the resistance between the Sensing and Diagnostic Module (SDM) harness connector C3 terminal 12 and RH side impact sensor connector terminal 1.

Is the measured resistance within the specified range?

0-0.5ohms

Go to Step 3

Go to Step 15

3

  1. Zero the J 39200 .
  2. Measure the resistance between SDM harness connector C3 terminal 10 and RH side impact sensor terminal 2.

Is the measured resistance within the specified range?

0-0.5ohms

Go to Step 4

Go to Step 16

4

  1. Zero the J 39200 .
  2. Measure the resistance between the SDM harness connector C3 terminals 9 and RH side impact sensor terminal 3.

Is the resistance measured less than the specified value?

0-0.5ohms

Go to Step 5

Go to Step 17

5

  1. Zero the J 39200 .
  2. Measure the resistance between the SDM harness connector C3 terminals 7 and RH side impact sensor terminal 4.

Is the resistance measured less than the specified value?

0-0.5ohms

Go to Step 6

Go to Step 18

6

Measure the resistance between the SDM harness connector C3 terminal 12 and ground.

Is the resistance measured equal to the specified value?

OL

(Infinite)

Go to Step 7

Go to Step 19

7

Measure the resistance between the SDM harness connector C3 terminal 10 and ground.

Is the resistance measured equal to the specified value?

OL

(Infinite)

Go to Step 8

Go to Step 20

8

Measure the resistance between the SDM harness connector C3 terminal 9 and ground.

Is the resistance measured less than the specified value?

OL

(Infinite)

Go to Step 9

Go to Step 21

9

Measure the resistance between the SDM harness connector C3 terminal 7 and ground.

Is the resistance measured equal to the specified value?

OL

(Infinite)

Go to Step 10

Go to Step 22

10

Measure the voltage between the SDM harness connector C3 terminal 12 and ground.

Is the voltage measured less than the specified value?

1 V

Go to Step 11

Go to Step 23

11

Measure the voltage between the SDM harness connector C3 terminal 10 and ground.

Is the voltage measured less than the specified value?

1 V

Go to Step 12

Go to Step 24

12

Measure the voltage between the SDM harness connector C3 terminal 9 and ground.

Is the voltage measured less than the specified value?

1 V

Go to Step 13

Go to Step 25

13

Measure the voltage between the SDM harness connector C3 terminal 7 and ground.

Is the voltage measured less than the specified value?

1 V

Go to Step 14

Go to Step 26

14

Inspect the RH side impact sensor harness for damage which may cause a short between the circuits.

Is any damage evident?

--

Go to Step 27

Go to Step 28

15

Repair an open or high resistance condition in the PNK wire. Refer to Wiring Repair .

Are the repairs complete?

--

Go to Step 30

--

16

Repair an open or high resistance condition in the BLU/YEL wire. Refer to Wiring Repair .

Are the repairs complete?

--

Go to Step 30

--

17

Repair an open or high resistance condition in the LT GRN wire. Refer to Wiring Repair .

Are the repairs complete?

--

Go to Step 30

--

18

Repair an open or high resistance condition in the GRY wire. Refer to Wiring Repair .

Are the repairs complete?

--

Go to Step 30

--

19

Repair a short to ground in the PNK wire. Refer to Wiring Repair .

Are the repairs complete?

--

Go to Step 30

--

20

Repair a short to ground in the BLU/YEL wire. Refer to Wiring Repair .

Are the repairs complete?

--

Go to Step 30

--

21

Repair a short to ground in the LT GRN wire. Refer to Wiring Repair .

Are the repairs complete?

--

Go to Step 30

--

22

Repair a short to ground in the GRY wire. Refer to Wiring Repair .

Are the repairs complete?

--

Go to Step 30

--

23

Repair a short to voltage in the PNK wire. Refer to Wiring Repair .

Are all the repairs complete?

--

Go to Step 30

--

24

Repair a short to voltage in the BLU/YEL wire. Refer to Wiring Repair .

Are the repairs complete?

--

Go to Step 30

--

25

Repair a short to voltage in the LT GRN wire. Refer to Wiring Repair .

Are the repairs complete?

--

Go to Step 30

--

26

Repair a short to voltage in the GRY wire. Refer to Wiring Repair .

Are the repairs complete?

--

Go to Step 30

--

27

Repair the RH side impact sensor harness. Refer to Wiring Repair .

Are the repairs complete?

--

Go to Step 30

--

28

  1. Replace the RH side impact sensor. Refer to Inflatable Restraint Side Impact Sensor Replacement .
  2. Turn the ignition switch to the ON position and wait 20 seconds.

Is DTC 32 present?

--

Go to Step 29

Go to SIR Diagnostic System Check

29

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

Are the repairs complete?

--

Go to Step 30

--

30

Reconnect all SIR components. Make sure all components are properly mounted.

Have all the SIR components been reconnected and properly mounted?

--

Go to SIR Diagnostic System Check

--