GM Service Manual Online
For 1990-2009 cars only

Object Number: 490888  Size: SF
SIR Components
Power, Ground, Side Impact Sensor, and Frontal Air Bags
Handling ESD Sensitive Parts Notice
SIR Caution

Circuit Description

When you first turn ON the ignition, the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. Then the SDM performs the following continuous diagnostic tests on the deployment loops:

    â€¢ Deployment loop voltage out of range test
    â€¢ Deployment loop resistance measurement test

If the voltage out of range test detects a short to voltage condition, the resistance measurement test for that deployment loop will not be performed.

Conditions for Running the DTC

Deployment loop voltage out of range test:

    â€¢ Ignition 1 voltage is within the normal operating voltage range.
    â€¢ Passenger frontal deployment loop is not shorted to voltage.
    â€¢ Passenger frontal high terminal A3 of connector C1 is less than 2 volts.

Deployment loop resistance measurement test:

    â€¢ Ignition 1 voltage is within the normal operating voltage range.
    â€¢ Passenger frontal deployment loop is not shorted to voltage.
    â€¢ Passenger frontal deployment loop is not shorted to ground.

Conditions for Setting the DTC

Deployment loop voltage out of range test - Passenger frontal deployment loop resistance is at least 6 ohms for 300 milliseconds.

Deployment loop resistance measurement test - Passenger frontal deployment loop resistance is more than 3.7 ohms for 300 milliseconds.

Action Taken When the DTC Sets

The SDM commands ON the AIR BAG warning lamp via Class 2 serial data.

Conditions for Clearing the DTC

    â€¢ You can issue a CLEAR CODES command
    â€¢ A history DTC will clear once 255 malfunction free ignition cycles have occurred

Diagnostic Aids

The following can cause an intermittent condition:

    â€¢ The inflatable restraint IP module yellow 2-way connector.
    â€¢ The 4-way inline connector C218.
    â€¢  The SDM wiring harness connector C1.
    â€¢ The wire to terminal connections in the passenger frontal high circuit.
    â€¢ The wire to terminal connections in the passenger frontal low circuit.
    â€¢ Refer to cell-id="62112">Testing for Intermittent and Poor Connections> in Wiring Systems.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. This step checks the inline connector C218.

  2. This step isolates the malfunction to one side of inline connector C218.

  3. This step checks the inflatable restraint IP module yellow 2-way connector.

  4. This step determines if there is an open or high resistance in either the passenger frontal high or the passenger frontal low circuits in the wiring harness between the inflatable restraint IP module yellow 2-way connector and inline connector C218 or if there is a malfunctioning inflatable restraint IP module.

  5. This step checks the SDM wiring harness connector C1.

  6. This step checks to see if there is an open or a high resistance in the passenger frontal high circuit in the wiring harness between inline connector C218 and the SDM wiring harness connector C1.

  7. This step determines if there is an open or high resistance in the passenger frontal low circuit in the wiring harness between inline connector C218 and the SDM wiring harness connector or if there is a malfunctioning SDM.

Step

Action

Value(s)

Yes

No

1

Did you perform A Diagnostic System Check - SIR?

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Go to Step 2

Go to cell-id="57882">A Diagnostic System Check - SIR>

2

  1. Turn OFF the ignition.
  2. Disconnect the 4-way inline connector C218.
  3. Inspect the male and female sides of inline connector C218 for the following conditions:
  4. • Corrosion
    • Damaged terminals
    • Poor connections/terminal tension
  5. Refer to cell-id="62112">Testing for Intermittent and Poor Connections> in Wiring Systems.

Does either the male or female side of inline connector C218 exhibit any signs of corrosion, terminal damage, or poor connections?

--

Go to Step 3

Go to Step 4

3

  1. If the female side of the inline connector is damaged, the wiring harness must be replaced.
  2. If the male side of the inline connector is damaged, replace the male side of the connector. Refer to cell-id="61973">Connector Repairs> in Wiring Systems.

Did you complete the repair?

--

Go to Step 18

--

4

  1. Reconnect the 4-way inline connector C218.
  2. Verify that the connector position assurance (CPA) is properly installed.
  3. Turn ON the ignition, with the engine OFF.
  4. Use the scan tool to request the SIR DTC display.

Does the scan tool indicate that this DTC is current?

--

Go to Step 5

Go to Diagnostic Aids

5

  1. Turn OFF the ignition.
  2. Disconnect the 4-way inline connector C218.
  3. Use the J 38715-80 adaptor to connect the J 38715-A SIR Driver/Passenger Load Tool PASSENGER INFLATOR and BASE OF COLUMN connectors to the male side of inline connector C218.
  4. Turn ON the ignition, with the engine OFF.
  5. Use the scan tool to request the SIR DTC display.

Does the scan tool indicate that this DTC is current?

--

Go to Step 11

Go to Step 6

6

  1. Turn OFF the ignition.
  2. Disconnect the inflatable restraint IP module yellow 2-way connector. Refer to cell-id="57777">Inflatable Restraint Instrument Panel Module Replacement> .
  3. Inspect the component and harness sides of the inflatable restraint IP module yellow 2-way connector for the following conditions:
  4. • Corrosion
    • Damaged terminals
    • Poor connections/terminal tension
  5. Refer to cell-id="62112">Testing for Intermittent and Poor Connections> in Wiring Systems.

Does either the component or harness side of the inflatable restraint IP module yellow 2-way connector exhibit any signs of corrosion, terminal damage, or poor connections?

--

Go to Step 7

Go to Step 8

7

  1. If the component side of the inflatable restraint IP module yellow 2-way connector is damaged, the inflatable restraint IP module must be replaced.
  2. If the harness side of the inflatable restraint IP module yellow 2-way connector is damaged, replace the harness side of the connector. Refer to cell-id="61973">Connector Repairs> in Wiring Systems.

Did you complete the repair?

--

Go to Step 18

--

8

  1. Turn OFF the ignition.
  2. Remove the J 38715-A .
  3. Reconnect the 4-way inline connector C218.
  4. Connect the J 38715-A PASSENGER INFLATOR connector to the harness side of the inflatable restraint IP module yellow 2-way connector.
  5. Turn ON the ignition, with the engine OFF.
  6. Use the scan tool to request the SIR DTC display.

Does the scan tool indicate that this DTC is current?

--

Go to Step 9

Go to Step 10

9

  1. Turn OFF the ignition.
  2. Locate and repair the open or the high resistance in either the passenger frontal high or passenger frontal low circuits in the wiring harness between the inflatable restraint IP module yellow 2-way connector and inline connector C218. Refer to cell-id="62194">Circuit Testing> and cell-id="61965">Wiring Repairs> in Wiring Systems.

Did you complete the repair?

--

Go to Step 18

--

10

  1. Turn OFF the ignition.
  2. Replace the inflatable restraint IP module. Refer to cell-id="57777">Inflatable Restraint Instrument Panel Module Replacement> .

Did you complete the replacement?

--

Go to Step 18

--

11

  1. Turn OFF the ignition.
  2. Remove the J 38715-A .
  3. Disconnect the inflatable restraint sensing and diagnostic module (SDM) wiring harness connector C1. Refer to cell-id="57768">Inflatable Restraint Sensing and Diagnostic Module Replacement> or cell-id="57768">Inflatable Restraint Sensing and Diagnostic Module Replacement> .
  4. Inspect the SDM wiring harness connector for the following conditions:
  5. • Corrosion
    • Damaged terminals
    • Poor connections/terminal tension
  6. Refer to cell-id="62112">Testing for Intermittent and Poor Connections> in Wiring Systems.

Does the SDM wiring harness connector exhibit any signs of corrosion, terminal damage, or poor connections?

--

Go to Step 12

Go to Step 13

12

Replace the SDM wiring harness connector. Refer to cell-id="61973">Connector Repairs> in Wiring Systems.

Did you complete the repair?

--

Go to Step 18

--

13

  1. Zero the J 39200 Digital Multimeter (DMM).
  2. Use the DMM to measure the resistance of the passenger frontal high circuit in the wiring between the 4-way inline connector C218 and the SDM wiring harness connector.

Does the resistance measure less than the specified value?

0.5 ohms

Go to Step 15

Go to Step 14

14

Locate and repair the open or high resistance in the passenger frontal high circuit in the wiring harness between the inline connector C218 and the SDM wiring harness connector. Refer to cell-id="62194">Circuit Testing> and cell-id="61965">Wiring Repairs> in Wiring Systems.

Did you complete the repair?

--

Go to Step 18

--

15

Use the DMM to measure the resistance of the passenger frontal low circuit in the wiring harness between the 4-way inline connector C218 and the SDM wiring harness connector.

Does the resistance measure less than the specified value?

0.5 ohms

Go to Step 17

Go to Step 16

16

Locate and repair the open or high resistance in the passenger frontal low circuit in the wiring harness between the inline connector C218 and the SDM wiring harness connector. Refer to cell-id="62194">Circuit Testing> and cell-id="61965">Wiring Repairs> in Wiring Systems.

Did you complete the repair?

--

Go to Step 18

--

17

Replace the SDM. Refer to cell-id="57768">Inflatable Restraint Sensing and Diagnostic Module Replacement> or cell-id="57768">Inflatable Restraint Sensing and Diagnostic Module Replacement> .

Did you complete the replacement?

--

Go to Step 18

--

18

  1. Reconnect all SIR components.
  2. Verify that all components and connectors are properly mounted.
  3. Turn ON the ignition, with the engine OFF.
  4. Use the scan tool in order to clear the DTCs.

Did you complete the action?

--

Go to cell-id="57882">A Diagnostic System Check - SIR>

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