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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2000 🢒 DeVille 🢒 DTC 🢒 DTC B0074 Supplemental Deployment Loop #1 Open

Object Number: 428438 Size: MF
SIR Components
SDM, Front and Rear Side Inflator Modules with Option AW9
SIR Handling Caution
Handling ESD Sensitive Parts Notice
SIR Schematic Icons

Circuit Description

The supplemental deployment loop #1 (LR/driver rear side inflatable module) is a 2 wire circuit. When you first turn ON the ignition, the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. Then the SDM performs the following continuous diagnostic tests on the deployment loops:

    • Deployment loop voltage out of range test
    • Deployment loop resistance measurement test

If the voltage out of range test detects a short to voltage condition, the resistance measurement test for that deployment loop will not be performed.

Conditions for Running the DTC
    • The ignition 1 voltage is within the normal operating voltage range.
    • The LR side deployment loop is not shorted to voltage.
    • The LR side high terminal is more than 2.4 volts.

Deployment loop resistance measurement test:

    • The ignition 1 voltage is within the normal operating voltage range.
    • The LR side deployment loop is not shorted to voltage.
    • The LR side deployment loop is not shorted to ground.

Conditions for Setting the DTC
    • Deployment loop voltage out of range test - The LR side high is less than 2.4 volts, the LR side loop resistance is greater or equal to 6 ohms for 500 milliseconds.
    • Deployment loop resistance measurement test - The LR side deployment loop resistance is more than 4.8 ohms for 500 milliseconds.

Action Taken When the DTC Sets

The SDM commands ON the AIR BAG warning lamp via Class 2 serial data.

Conditions for Clearing the DTC
    • The LR side deployment loop resistance is 4.8 ohms or less for 500 milliseconds.
    • The LR side high is more than 2.4 volts, the LR side loop resistance is less than 6 ohms for 500 milliseconds.
    • You can issue a CLEAR CODES command.
    • A history DTC will clear once 255 malfunction free ignition cycles have occurred.

Diagnostic Aids

The following can cause an intermittent condition:

    • The LR side harness connector
    • The SDM wiring harness connector
    • The wire to terminal connections in the LR side high circuit
    • The wire to terminal connections in the LR side low circuit

If any of the above conditions are found refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. This step checks the LR/driver rear side inflator module in-line connector.

    2.

  2. This step checks to see if there is a malfunctioning LR side inflator module.

    3.

  3. This step checks to see if the inflatable restraint sensing and diagnostic module (SDM) wiring harness connector is OK.

    4.

  4. This step checks to see if there is an open or a high resistance in the LR side high deployment circuit.

    5.

  5. This step determines if there is an open or high resistance in the LR side low deployment circuit or if there is a malfunctioning SDM.

Step

Action

Value(s)

Yes

No

1

Did you perform the Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - SIR

2
  1. Turn OFF the ignition.
  2. Disconnect the LR/driver rear side inflator module in-line connector. Refer to Rear Seat Body Side Inflatable Restraint Module Replacement .
  3. Inspect both of the wiring harness in-line connectors for any of the following conditions:
    4. • Corrosion
    • Terminal damaged
    • Poor connections/terminal tension
  4. If any of the above conditions are found refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Do the connectors exhibit any signs of corrosion, terminal damaged, or poor connections?

--

Go to Step 3

Go to Step 4

3

Replace the vehicle wiring harness side of the in-line connector. Refer to Connector Repairs in Wiring Systems.

Did you complete the replacement?

--

Go to Step 14

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4
  1. Reconnect the LR side in-line connector.
  2. Verify that the connector position assurance (CPA) is properly installed.
  3. Install a scan tool.
  4. Turn ON the ignition, with the engine OFF.
  5. Use the scan tool to request SIR DTCs displayed.

Does the scan tool indicate that this DTC is current?

--

Go to Step 5

Go to Diagnostic Aids

5
  1. Turn OFF the ignition.
  2. Disconnect the in-line connector.
  3. Install the J 38715-A SIR Load Tool to the wiring harness vehicle side in-line connector. Use appropriate connector adaptors where necessary.
  4. Turn ON the ignition, with the engine OFF.
  5. Use the scan tool to request SIR DTCs displayed.

Does the scan tool indicate that this DTC is current?

--

Go to Step 7

Go to Step 6

6
  1. Turn OFF the ignition.
  2. Replace the LR side inflator module. Refer to Rear Seat Body Side Inflatable Restraint Module Replacement .

Did you complete the replacement?

--

Go to Step 14

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7
  1. Turn OFF the ignition.
  2. Remove the J 38715-A .
  3. Disconnect the inflatable restraint sensing and diagnostic module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  4. Check for the proper connection of the LR side high and the low deployment circuit terminals of the SDM wiring harness connector.

Is the SDM wiring harness connector OK?

--

Go to Step 9

Go to Step 8

8

Repair or replace the SDM wiring harness connector. Refer to Connector Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 14

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9

Use the J 39200 DMM and measure the resistance between the driver rear side high deployment circuit in-line connector terminal and the SDM wiring harness connector terminal.

Does the resistance measure greater than the specified value?

0-0.5 ohms

Go to Step 10

Go to Step 11

10

Locate and repair the open or high resistance in the LR side high deployment circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 14

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11

Use the J 39200 and measure the resistance between the LR side low deployment circuit in-line connector terminal and the SDM wiring harness connector terminal.

Does the resistance measure greater than the specified value?

0-0.5 ohms

Go to Step 12

Go to Step 13

12

Locate and repair the open or high resistance in the LR side low deployment circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 14

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13

Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .

Did you complete the replacement?

--

Go to Step 14

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14
  1. Reconnect all of the SIR components.
  2. Verify that all of the 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.

Did you complete the action?

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Go to Diagnostic System Check - SIR

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