GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 Avalanche - 4WD 🢒 Restraints 🢒 SIR 🢒 DTC B0040, B0041, or B0045

Circuit Description

The inflatable restraint side impact module deployment loop consists of a side impact module, side impact module high control, and side impact module low control circuits. A shorting bar is used on the side impact module connector which will short together the side impact module high and side impact module low control circuits when the connector is disconnected. This will help to prevent unwanted deployment of the inflator module during servicing. When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) performs continuous diagnostic tests on the deployment loops to check for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a diagnostic trouble code (DTC) will be stored in memory.

Conditions for Running the DTC

Ignition 1 voltage is within the normal operating voltage range.

Conditions for Setting the DTC
    • DTC B0040 will set when the SDM detects the LF side impact module deployment loop resistance is less than 1.3 ohms for 500 milliseconds.
    • DTC B0041 will set when one of the following conditions occurs:
       - The SDM detects the LF side impact module deployment loop resistance is greater than 4.8 ohms for 500 milliseconds.
       - The SDM detects the voltage at LF side impact module high control is less than 2.4 volts and LF side impact module deployment loop resistance is 6 ohms or greater for 500 milliseconds.
    • DTC B0045 will set when one of the following conditions occur:
       - The SDM detects the voltage at LF side impact module high control is greater than 6 volts for 500 milliseconds.
       - The SDM detects the voltage at LF side impact module high control is less than 2.4 volts and LF side impact module deployment loop resistance is less than 6 ohms for 500 milliseconds.

Action Taken When the DTC Sets

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

Conditions for Clearing the DTC
    • The condition responsible for setting the DTC no longer exists.
    • You issue a scan tool CLEAR DTCs 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 LF side impact module high and LF side impact module low control circuits
    • An open or high resistance in the LF side impact module high or LF side impact module low control circuits
    • A malfunctioning shorting bar on the LF side impact module connector

Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Inspects the LF side impact module in-line connector.

    2.

  2. Tests for a malfunctioning LF side impact module.

    3.

  3. If DTC B0040 is present, test for a short between the LF side impact module high and LF side impact low control circuits. If DTC B0041 is present, test for an open or high resistance in the LF side impact module high and LF side impact module low control circuits. If DTC B0045 is present, test for a short to ground or voltage in the LF side impact module high and LF side impact module low control circuits.

Step

Action

Yes

No

Schematic Reference: SIR Schematics

Connector End View Reference: SIR Connector End Views

1

Did you perform the Diagnostic System Check - SIR?

Go to Step 2

Go to Diagnostic System Check - SIR

2

  1. Turn OFF the ignition.
  2. Disconnect the LF side impact module in-line connector located under the seat. Refer to Driver and Passenger Seat Side Inflatable Restraint Module Replacement .
  3. Inspect both halves of the connector for the following conditions:
    4. • Corrosion
    • Terminal damage
    • Poor connections/terminal tension

Do the connectors exhibit any signs of corrosion, terminal damage, or poor connections?

Go to Step 3

Go to Step 4

3
  1. If the LF side impact module harness connector exhibits any of the above conditions, replace the LF side impact module wiring harness. Refer to Driver and Passenger Seat Side Inflatable Restraint Module Replacement .
  2. Replace the harness side of the LF side impact module in-line connector. Refer to Connector Repairs in Wiring Systems.

Did you complete the replacement?

Go to Step 11

--

4

  1. Install the J 38715-A SIR Load Tool to the harness side of the LF side impact module in-line connector located under the seat.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, request the SIR DTC display.

Does the scan tool indicate that either DTC B0040, B0041, or B0045 is current?

Go to Step 6

Go to Step 5

5
  1. Turn OFF the ignition.
  2. Disconnect the J 38715-A .
  3. Reconnect the LF side impact module in-line connector.
  4. Remove the LF side impact module connector located at the module. Refer to Driver and Passenger Seat Side Inflatable Restraint Module Replacement .
  5. Use the J 38715-30A adapter to connect the J 38715-A to the LF side impact module connector.
  6. Turn ON the ignition, with the engine OFF.
  7. With a scan tool, request the SIR DTC display.

Does the scan tool indicate that either DTC B0040, B0041, or B0045 is current?

Go to Step 10

Go to Step 9

6
  1. Turn OFF the ignition.
  2. Remove the J 38715-A .
  3. Disconnect the SDM connector. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  4. Inspect the SDM connector for corrosion or damage. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 7

7

  1. If DTC B0040 is present, test the LF side impact module high and LF side impact module low control circuits for a short. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
  2. If DTC B0041 is present, test the LF side impact module high and LF side impact module low control circuits for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
  3. If DTC B0045 is present, test the LF side impact module high and LF side impact module low control circuits for a short to ground or voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 8

8

Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .

Did you complete the replacement?

Go to Step 11

--

9

Replace the LF side impact module. Refer to Driver and Passenger Seat Side Inflatable Restraint Module Replacement .

Did you complete the replacement?

Go to Step 11

--

10

Replace the LF side impact module wiring harness. Refer to Driver and Passenger Seat Side Inflatable Restraint Module Replacement .

Did you complete the replacement?

Go to Step 11

--

11
  1. Reconnect all SIR system components.
  2. Verify that all components, connectors and 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