GM Service Manual Online
For 1990-2009 cars only

Object Number: 541428  Size: SF
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SRS Schematic Icons

Circuit Description

When you first turn ON the ignition, the supplemental 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:

    • Deployment loop voltage out of range test
    • Deployment loop resistance mearurement 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

    • Ignition 1 voltage is within the normal operating voltage range.
    • Passenger frontal deployment loop is not open.
    • Passenger frontal deployment loop is not shorted to voltage.
    • Passenger frontal deployment loop is not shorted to ground.

Conditions for Setting the DTC

Passenger frontal deployment loop resistance is less than 1.3 ohms for 500 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

    • You can issue a CLEAR CODE command
    • A history DTC will clear once 255 malfunction free ignition cycles have occurred

Diagnostic Aids

The following can cause an intermittent condition:

    • A short between the passenger frontal high and the passenger frontal low circuits.
    • A malfunctioning shorting bar on the supplemental restraint IP module 2-way connector.
    • Refer to Testing for Intermittent Conditions and Poor Connections Testing for Intermittents 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 IP/passenger inflator module in-line connector for physical damage.

  2. This step checks to see if there is a malfunctioning supplemental restraint passenger inflator module.

  3. This step determines if there is a short between passenger frontal high and low deployment circuits or if there is a malfunctioning SDM.

Step

Action

Value(s)

Yes

No

1

Did you perform the A Diagnostic System Check-SRS?

--

Go to Step 2

Go to Diagnostic System Check - SRS

2

  1. Turn OFF the ignition.
  2. Disconnect supplemental restraint IP/passenger inflator module in-line connector.
  3. Inspect the wiring harness in-line connector for the following conditions:
  4. • Corrosion
    • Terminal damaged
    • Poor connections/terminal tension
  5. Refer to Testing for Intermittent Conditions and Poor Connections

Does connector exhibits any signs of corrosion, terminal damaged, or poor connections?

--

Go to Step 3

Go to Step 4

3

Replace the wiring harness side of in-line connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you complete the replacement?

--

Go to Step 10

--

4

  1. Reconnect supplemental restraint IP module in-line connector.
  2. Make sure that the connector position assurance (CPA) is properly installed.
  3. Install a scan tool.
  4. Turn ON the ignition, with the engine OFF.
  5. Use the scan tool to retrieve DTCs.

Is DTC retrieved as current?

--

Go to Step 5

Go to Diagnostic Aids

5

  1. Turn OFF the ignition.
  2. Disconnect in-line connector.
  3. Install the SIR Load Tool to the wiring harness side in-line connector. Use appropriate connector adaptors where necessary.
  4. Turn ON the ignition, with the engine OFF.
  5. Use the scan tool to retrieve DTCs.

Is DTC retrieved as current?

--

Go to Step 7

Go to Step 6

6

  1. Turn OFF the ignition.
  2. Replace the supplemental restraint passenger inflator module. Refer to Supplemental Restraint Instrument Panel Module Replacement .

Did you complete the replacement?

--

Go to Step 10

--

7

  1. Turn OFF the ignition.
  2. Remove the SIR Load Tool.
  3. Disconnect the supplemental restraint sensing and diagnostic module (SDM). Refer to Supplemental Restraint Sensing and Diagnostic Module Replacement .
  4. Using DMM measure the resistance between the passenger frontal high circuit and passenger frontal low circuit on the supplemental restraint sensing and diagnostic module (SDM) connector.

Is the measured resistance less than the specified value?

OL

Go to Step 8

Go to Step 9

8

Locate and repair the short between high and low deployment circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 10

--

9

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

Did you complete the replacement?

--

Go to Step 10

--

10

  1. Reconnect all SRS components.
  2. Verify that all components, connectors and CPAs are properly mounted.
  3. Clear the DTCs using the scan tool
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Did you complete the action?

--

Go to Step 2

System OK