GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2005 🢒 Century 🢒 DTC 🢒 DTC B0040, B0041, or B0045

Circuit Description

The driver side deployment loop consists the following components:

    • An inflatable restraint side impact module - LF
    • The side impact module - LF high circuits
    • The side impact module - LF low 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 DTC will be stored.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

    • DTC B0040 Left Front Side Deployment Loop Resistance Low
    • DTC B0041 Left Front Side Deployment Loop Open
    • DTC B0045 Left Front Side Deployment Loop Voltage Out of Range

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 occurs:
       - 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 ON the AIR BAG indicator 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 module 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 - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Turn OFF the ignition.
  2. Disconnect the LF side impact module in-line connector. Refer to Inflatable Restraint Side Impact Module Replacement - Left Side .
  3. Inspect the component and LF side impact module harness sides of the in-line connector for the for damage or corrosion that may cause the malfunction. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Does connector exhibits any signs of damage or corrosion?

Go to Step 3

Go to Step 4

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

Did you complete the replacement?

Go to Step 9

--

4

  1. Install the J 38715-A SIR Load Tool to the harness side of the LF side impact module in-line connector. Use PASSENGER INFLATOR connector.
  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 5

Go to Step 8

5
  1. Turn OFF the ignition.
  2. Remove the J 38715-A .
  3. Disconnect the inflatable restraint sensing and diagnostic module (SDM) connector. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
  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 9

Go to Step 6

6

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

Did you find and correct the condition?

Go to Step 9

Go to Step 7

7

Replace the SDM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 9

--

8

Replace the LF side impact module. Refer to Inflatable Restraint Side Impact Module Replacement - Left Side .

Did you complete the replacement?

Go to Step 9

--

9
  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