GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2007 🢒 Epica 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC B1479

Circuit Description

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

Upon passing these tests, 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 deploy loops.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1479 Right Roof Rail Deployment Loop Short to Ground

Conditions for Running the DTC

Ignition voltage is within the normal operating voltage range.

Conditions for Setting the DTC
    • The roof rail air bag wiring of the passenger high is shorted to ground.
    • The roof rail air bag wiring of the passenegr low is shorted to ground.

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

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

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

Schematic Reference: SIR Schematics

Connector End View Reference: SIR Connector End Views

1

Did you perform a Diagnostic System Check - Vehicle?

 

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Confirm the ignition switch is OFF and the sensing and diagnostic module (SDM) fuse has been removed.
  2. Wait for 1 minute for the SDM charger to be discharged.

Has the SDM discharged?

--

Go to Step 3

--

3

Visually inspect any damage for the air bag wiring.

Is the air bag wiring damaged?

--

Go to Step 5

Go to Step 4

4
  1. Confirm the ignition switch is OFF.
  2. Disconnect the right roof rail air bag module connector.
  3. Disconnect the SDM connector.
  4. Measure the resistance between the high, low wiring of the left roof rail module harness connector and ground.

Is the resistance greater than the specified value?

10K ohms

Go to Step 6

Go to Step 5

5

Replace the air bag wiring.

Is the replacement complete?

--

Go to Step 8

--

6
  1. Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  2. Confirm the ignition switch is ON.
  3. Use the scan tool in order to clear the DTCs.
  4. Perform the Diagnostic System Check - Vehicle .

Is the DTC removed?

--

Go to Step 8

Go to Step 7

7

Replace the right roof rail module.

Is the replacement complete?

--

Go to Step 8

--

8
  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