GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2005 🢒 STS 🢒 DTC 🢒 DTC B0019 or B0020

Circuit Description

The passenger frontal deployment loop consists of the following components:

    • A dual stage inflatable restraint instrument panel (I/P) module
    • The I/P module high circuits for both stages 1 and  2
    • The I/P module low circuits for both stages 1 and  2

There are 2 shorting bars used within the I/P module connector which will short together both I/P module stage 1 high and low circuits and both I/P module stage 2 high and low circuits when the connector is disconnected, this will help to prevent unwanted deployment of the inflator module during servicing. During a frontal crash of sufficient force the inflatable restraint sensing and diagnostic module (SDM) will allow current to flow through the deployment loop in order to deploy the I/P module. 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 diagnostic trouble code (DTC) will be stored in memory.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

    • DTC B0019 Passenger Frontal Deployment Loop Stage 1
    • DTC B0020 Passenger Frontal Deployment Loop Stage 2

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

B0019 01 stage 1 or B0020 01 stage 2

The I/P module high and/or low circuit is short to voltage for 120 milliseconds.

B0019 02 stage 1 or B0020 02 stage 2

The I/P module high and/or low circuit is short to ground for 120 milliseconds.

B0019 04 stage 1 or B0020 04 stage 2

The I/P module high and/or low circuit is open for 120 milliseconds.

B0019 0D stage 1 or B0020 0D stage 2

The I/P module deployment loop resistance is more than 5.1 ohms for 120 milliseconds.

B0019 0E stage 1 or B0020 0E stage 2

The I/P module deployment loop resistance is less than 1.3 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 I/P module stage 1 or stage 2, high and low circuits
    • An open or a high resistance in the I/P module stage 1 or stage 2, high or low circuits
    • A short to ground or a short to voltage in the I/P module stage 1 or stage 2, high or low circuits
    • The I/P module connector
    • The SDM connector
    • A malfunctioning I/P module
    • 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 I/P module.

    2.

  2. If DTC B0019 01 or B0020 01 is present, test the I/P module for a short to battery voltage on the high and low circuits in stage 1 or stage 2. If DTC B0019 02 or B0020 02 is present, test the I/P module for a short to ground on the high and low circuits in stage 1 or stage 2. If DTC B0019 04, 0D, 0E or B0020 04, 0D, 0E is present, test the high and low circuits for an open circuit and for high or low resistance in stage 1 or stage 2.

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 instrument panel (I/P) module in-line connector. Refer to Inflatable Restraint Instrument Panel Module Replacement .
  3. Inspect the component and harness sides of the in-line connector for the I/P module 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 the connector exhibit any signs of damage or corrosion?

Go to Step 3

Go to Step 4

3
  1. If the in-line connector for the I/P module is damaged, the I/P module must be replaced. Refer to Inflatable Restraint Instrument Panel Module Replacement .
  2. If the wiring harness side of the I/P module 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 9

--

4

  1. Use the J 38715-80 Adapter to connect the J 38715-A Driver/Passenger SIR Load Tool to the harness side of the I/P module connector. Use BASE OF COLUMN 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. Install a scan tool, request the SIR DTC display.

Does the scan tool indicate that DTC B0019 or B0020 are current?

Go to Step 5

Go to Step 7

5
  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 I/P module stage 1 or stage 2 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 9

Go to Step 6

6

  1. If DTC B0019 01 or B0020 01 is present, test the I/P module for a short to battery voltage on the high and low circuits in stage 1 or stage 2.
  2. If DTC B0019 02 or B0020 02 is present, test the I/P module for a short to ground on the high and low circuits in stage 1 or stage 2.
  3. If DTC B0019 04, 0D, 0E or B0020 04, 0D, 0E is present, test the I/P module high and low circuits for an open and for high or low resistance in stage 1 or stage 2.
  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 9

Go to Step 8

7
  1. Turn OFF the ignition.
  2. Replace the I/P module. Refer to Inflatable Restraint Instrument Panel Module Replacement .

Did you complete the replacement?

Go to Step 9

--

8
  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 9

--

9
  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