GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Optra 🢒 DTC 🢒 DTC B1347

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.

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 deploy loops.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1347 Driver Frontal Deployment loop Stage 1 Resistance Below Threshold

Conditions for Running the DTC

Ignition voltage is within the normal operating voltage range.

Conditions for Setting the DTC
    • The resistance of the driver air bag deployment loop is lower than 1.8 ohms.
    • The shorting bar is damaged and the SDM must be replaced.

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: Component Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

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

Is the air bag wiring damaged?

--

Go to Step 6

Go to Step 3

3
  1. Confirm the ignition switch is OFF.
  2. Remove the steering wheel module.
  3. Disconnect the connector of the sensing and diagnostic module (SDM) wiring.
  4. Measure the resistance between terminal 29 and 30 of the SDM connector.

Is the resistance equal to the specified value?

∞

Go to Step 4

Go to Step 5

4
  1. Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  2. Confirm the ignition switch is ON.
  3. Erase the DTC using the scan tool.
  4. Perform the Diagnostic System Check - Vehicle .

Is the DTC removed?

--

System OK

Go to Step 8

5
  1. Remove the connector from the steering wheel module coil wiring.
  2. Measure the resistance between terminal 29 and 30 of the SDM.

Is the resistance equal to the specified value?

∞

Go to Step 7

Go to Step 6

6

Replace the air bag wiring.

Is the replacement complete?

--

Go to Step 9

--

7

Replace the steering wheel module coil. Refer to Inflatable Restraint Steering Wheel Module Coil Replacement .

Is the replacement complete?

--

Go to Step 9

--

8

Replace the steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .

Is the replacement complete?

--

Go to Step 9

--

9
  1. Reconnect all SIR system components.
  2. Verify that all components, connectors, and connector position assurances (CPAs) are properly mounted.
  3. Use the scan tool to clear the DTCs.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the text.

Does the DTC reset?

--

Go to Step 2

System OK