GM Service Manual Online
For 1990-2009 cars only

Circuit Description

When the ignition switch is turned to ON, the sensing and diagnostic module (SDM) will perform turn-on test to diagnose critical malfunctions within SDM itself.

Upon passing these test ignition and deployment loop voltages are measured to ensure that they are within their normal voltage ranges. The SDM monitors the voltages at the driver low and the passenger low to detect shorts to ground or voltage in the deployment loops.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1403 Passenger SIS Malfunction

Conditions for Running the DTC

Ignition voltage is within the normal operating voltage range.

Conditions for Setting the DTC

The passenger side impact sensor is inoperative.

Action Taken When the DTC Sets

The SDM commands the AIR BAG indicator ON.

Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

Step

Action

Values

Yes

No

Warning: Refer to Sensing and Diagnostic Module Voltage after Ignition is Turned Off Warning in the Preface section.

Warning: Refer to Sensing and Diagnostic Module Handling Warning in the Preface section.

Schematic Reference: SIR Schematics

Connector End View Reference: Component Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Visually inspect the connector and the wiring of the driver side air bag.

Is the wiring damaged?

--

Go to Step 4

Go to Step 3

3

  1. Confirm the ignition switch is OFF.
  2. Disconnect the connector of the passenger side impact module.
  3. Disconnect the connector of the sensing and diagnostic module (SDM).
  4. Measure the resistance between terminal 68, 69 of the SDM and terminal 1, 2 of the passenger side impact sensor connector.

Is the resistance equal to the specified value?

0 Ω

Go to Step 5

Go to Step 4

4

Replace the air bag wiring.

Is the replacement complete?

--

Go to Step 6

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5

Replace the driver side impact module.

Is the replacement complete?

--

Go to Step 6

--

6

  1. Reconnect all SIR components.
  2. Verify that all components, connectors and connector position assurances (CPAs) are properly mounted.
  3. Use the scan tool in order to clear the DTCs.
  4. Operate the vehicle within the Conditions for Running the DTC, as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK