GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2003 🢒 DeVille 🢒 Restraints 🢒 SIR 🢒 DTC B0040, B0041, or B0045

Circuit Description

The driver side deployment loop consists the following components:

    • An inflatable restraint side impact module-LF
    • The inflatable restraint side impact module wiring harness
    • 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.

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 side impact module-LF deployment loop resistance is less than 1.3 ohms for 500 milliseconds.
    • DTC B0041 will set when one of the following conditions occurs:
       - Side impact module-LF high circuit is less than 2.4 volts and the side impact module-LF deployment loop is more than 6 ohms for 500 milliseconds.
       - Side impact module-LF deployment loop resistance is more than 4.8 ohms for 500 milliseconds.
    • DTC B0045 will set when one of the following conditions occur:
       - Side impact module-LF high and/or low circuits is short to ground or short to voltage for 500 milliseconds.
       - Side impact module-LF high circuit is less than 2.4 volts and side impact module-LF 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 and the scan tool Clear DTCs function is used.
    • 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 in Wiring Systems.

Test Description

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

  1. Tests to see if the malfunction is caused by the side impact module-LF or by the side impact module-LF wiring harness.

    2.

  2. Tests to see what DTCs are present. If DTC B0040 s 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 A Diagnostic System Check - SIR?

Go to Step 2

Go to Diagnostic System Check - SIR

2
  1. Turn OFF the ignition.
  2. Disconnect the side impact module-LF wiring harness in-line connector. Refer to Inflatable Restraint Side Impact Module Wiring Harness Replacement .
  3. Inspect the component and harness sides of the in-line connector for the side impact module-LF wiring harness 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 in-line connector for the side impact module-LF wiring harness is damaged, the side impact module-LF wiring harness must be replaced. Refer to Inflatable Restraint Side Impact Module Wiring Harness Replacement .
  2. If the wiring harness side of side impact module-LF in-line connector is damaged, replace the harness side of the connector. Refer to Connector Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 11

--

4
  1. Use J 38715-60 adapter to connect the J 38715-A SIR Driver/Passenger Load Tool to the harness side of the side impact module-LF wiring harness connector. Use STEERING WHEEL and PASSENGER INFLATOR connectors.
  2. Turn ON the ignition, with the engine OFF.
  3. Use the scan tool to request SIR DTCs displayed.

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

Go to Step 6

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Disconnect and remove the J 38715-A and adapter.
  3. Connect the side impact module-LF wiring harness in-line connector.
  4. Remove the side impact module-LF connector. Refer to Driver and Passenger Seat Side Inflatable Restraint Module Replacement .
  5. Use J 38715-30A adapter to connect the J 38715-A to the side impact module-LF connector. Use PASSENGER INFLATOR connector.
  6. Turn ON the ignition, with the engine OFF.
  7. Use the scan tool to request SIR DTCs displayed.

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

Go to Step 9

Go to Step 8

6
  1. Turn OFF the ignition.
  2. Disconnect and remove both the J 38715-A and adapter.
  3. Disconnect the inflatable restraint sensing and diagnostic module (SDM) connector. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  4. Inspect the SDM connector for damage or corrosion that may cause a malfunction in the side impact module-LF high and/or low circuits. 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 side impact module-LF 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 in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 10

8
  1. Turn OFF the ignition.
  2. Replace the side impact module-LF. Refer to Driver and Passenger Seat Side Inflatable Restraint Module Replacement .

Did you complete the replacement?

Go to Step 11

--

9
  1. Turn OFF the ignition.
  2. Replace the side impact module-LF wiring harness. Refer to Inflatable Restraint Side Impact Module Wiring Harness Replacement .

Did you complete the replacement?

Go to Step 11

--

10
  1. Turn OFF the ignition.
  2. Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .

Did you complete the replacement?

Go to Step 11

--

11
  1. Connect all SIR components.
  2. Turn ON the ignition, with the engine OFF.
  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