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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2005 🢒 STS 🢒 Accessories 🢒 Navigation Systems 🢒 DTC B0021

Circuit Description

The driver side deployment loop consists of the following components:

    • An inflatable restraint side impact module - RF
    • The inflatable restraint side impact module wiring harness
    • The side impact module - RF high circuits
    • The side impact module - RF low circuits

A shorting bar is used within the side impact module - RF connector. The shorting bar will short together the side impact module - RF high circuit, and the side impact module - RF 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 - RF. 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 Descriptor

This diagnostic procedure supports the following DTC:

DTC B0021 Right Front Side Deployment Loop

This vehicle has DTCs which include DTC symptoms. For more information on DTC symptoms, refer to DTC Symptom Description in Vehicle DTC Information.

DTC Symptom

DTC Symptom Descriptor

01

Short to Battery

02

Short to Ground

04

Open Circuit

0D

Resistance above Threshold

0E

Resistance below Threshold

Conditions for Running the DTC

Ignition voltage is within the normal operating voltage range.

Conditions for Setting the DTC

B0021 01

The side impact module - RF high and/or low circuit is short to voltage for 120 milliseconds.

B0021 02

The side impact module - RF high and/or low circuit is short to ground for 120 milliseconds.

B0021 04

The side impact module - RF high and/or low circuit is open for 120 milliseconds.

B0021 0D

The side impact module - RF deployment loop resistance is more than 3.9 ohms for 120 milliseconds.

B0021 0E

The side impact module - RF deployment loop resistance is less than 1.1 ohms for 120 milliseconds.

Action Taken When the DTC Sets

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

Conditions for Clearing the MIL/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 - RF high and low circuits
    • An open or a high resistance in the side impact module - RF high or low circuits
    • A short to ground or a short to voltage in the side impact module - RF high or low circuits
    • The side impact module - RF connector
    • The SDM connector
    • A malfunctioning side impact module wiring harness
    • A malfunctioning side impact module - RF
    • 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 - RF or by the side impact - RF wiring harness.

    2.

  2. Tests to see what DTCs are present. If DTC B0021 01 is present, test the side impact module - RF for a short to battery voltage on the high and low circuits. If DTC B0021 02 is present, test the side impact module - RF for a short to ground on the high and low circuits. If DTC B0021 04, 0D, 0E is present, test the side impact module - RF test the high and low circuits for an open circuit and for high or low resistance.

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 side impact module - RF 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 - RF 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 - RF wiring harness is damaged, the side impact module - RF 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 - RF 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 the J 38715-60 Adapter to connect the J 38715-A Driver/Passenger SIR Load Tool to the harness side of the side impact module - RF wiring harness connector. Use STEERING WHEEL and PASSENGER INFLATOR connectors.
  2. Turn ON the ignition, with the engine OFF.

    3. Important: J-45289 CANdi module must be used with the scan tool.

  3. Use the scan tool to request SIR DTCs displayed.

Does the scan tool indicate that DTC B0014 is current?

Go to Step 6

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Disconnect and remove the J 38715-A and the adapter.
  3. Connect the side impact module - RF wiring harness in-line connector.
  4. Remove the side impact module - RF connector. 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 side impact module - RF 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 B0014 is 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 the adapter.
  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 damage or corrosion that may cause a malfunction in the side impact module - RF 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 B0021 01 is present, test the side impact module - RF for a short to battery voltage on the high and low circuits.
  2. If DTC B0021 02 is present, test the side impact module - RF for a short to ground on the high and low circuits.
  3. If DTC B0021 04, 0D, 0E is present, test the side impact module - RF high and low circuits for an open circuit and for high or low resistance.
  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 - RF. 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 - RF 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 Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

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