GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2006 🢒 Rendezvous - FWD 🢒 Accessories 🢒 Navigation Systems 🢒 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 within the side impact module LF connector. The shorting bar will short together the side impact module LF high circuit and the side impact module LF low circuit when the connector is disconnected. This helps prevent unwanted deployment of the inflator module during servicing. During a side or frontal crash of sufficient force, the inflatable restraint sensing and diagnostic module (SDM) will allow current to flow through the deployment loop. This flow of current will deploy the side impact module LF. The 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 in memory.

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 the 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 the LF side impact module high control is greater than 6 volts for 500 milliseconds.
       - The SDM detects the voltage at the LF side impact module high control is less than 2.4 volts and the 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 is 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 are possible causes of the malfunction:

    • A short between the side impact module LF high and low circuits
    • An open or a high resistance in the side impact module LF high or low circuits
    • A short to ground or a short to voltage in the side impact module LF high or low circuits
    • The side impact module LF connector
    • The SDM connector
    • A malfunctioning side impact module LF
    • A malfunctioning SDM

Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction. If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections .

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step tests to see what DTCs are present. If DTC B0040 is present, test the side impact module LF for a short between high and low circuits. If DTC B0041 is present, test the side impact module LF high and low circuits for an open and for high resistance. If DTC B0045 is present, test the side impact module LF high and low circuits for a short to ground or a short to voltage.

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

2

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

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 harness 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. Replace the harness side of the LF side impact module in-line connector. Refer to Connector Repairs .

Did you complete the replacement?

Go to Step 9

--

4

    Important: If the scan tool displays multiple codes, diagnose the open code first.

  1. Install the J 38715-A SIR Driver/Passenger Load Tool to the harness side of the side impact module LF inline 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 7

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 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 .

Did you find and correct the condition?

Go to Step 9

Go to Step 6

6

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

Did you find and correct the condition?

Go to Step 9

Go to Step 8

7
  1. Turn OFF the ignition.
  2. Replace the side impact module LF. Refer to Inflatable Restraint Side Impact Module Replacement - Left Side .

Did you complete the replacement?

Go to Step 9

--

8
  1. Turn OFF the ignition.
  2. Replace the SDM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

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 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