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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1999 🢒 Eldorado 🢒 Restraints 🢒 SIR 🢒 DTC B1122 Driver Deployment Loop Resistance Low

Object Number: 381186 Size: MF
SIR Components
SIR Schematics DeVille
SIR Schematics Eldorado
SIR Caution
Handling ESD Sensitive Parts Notice
SIR Schematic Icons
SIR Schematic Icons

Circuit Description

When you first turn the ignition switch to the RUN position, the inflatable restraint sensing and diagnostic module (SDM) performs tests in order to diagnose the critical malfunctions within the module. The SDM measures the ignition positive voltage and the deployment loop voltages in order to ensure that they are within their respective normal voltage ranges. Then the SDM proceeds using the RESISTANCE MEASUREMENT test. During one portion of the RESISTANCE MEASUREMENT test, the SDM performs the following functions:

    • Grounds the DRIVER FRONTAL LOW terminal 9 through an internal current sink.
    • Connects the DRIVER FRONTAL HIGH terminal 10 to an internal constant current source. This current produces proportional voltage drops in the deployment loop.
    • Measures the voltage difference between the DRIVER FRONTAL HIGH and the DRIVER FRONTAL LOW.
    • Calculates the resistance of the driver frontal deployment loop using the measured voltage.

Conditions for Setting the DTC
    • The driver and passenger frontal deployment loops are not open.
    • The driver and passenger frontal deployment loops are not shorted to voltage.
    • The driver and passenger frontal deployment loops are not shorted to ground.
    • The driver frontal deployment loop resistance is less than 1.7 ohms. The driver frontal deployment loop consists of the following components:
       - The inflatable restraint steering wheel module.
       - The inflatable restraint steering wheel module coil.
       - The harness wiring of CKT 347
       - The harness wiring of CKT 348
       - The connector terminal contact.

The RESISTANCE MEASUREMENT test checks for this malfunction. This test only occurs once each ignition cycle when Ignition Positive Voltage is within the normal operating voltage range.

Action Taken When the DTC Sets
    • The SDM sets a Diagnostic Trouble Code.
    • The SDM commands the instrument panel cluster (IPC) to turn ON the AIR BAG warning lamp.

Conditions for Clearing the MIL/DTC
    • Current DTC
        The resistance of the driver frontal deployment loop is more than 1.7 ohms and the ignition switch is cycled.
    • History DTC
       - You issue a scan tool CLEAR CODES command.
       - 250 malfunction free ignition cycles occur.

When you issue a scan tool CLEAR CODES command and the malfunction is still present, the DTC will not reappear until the next ignition cycle.

Diagnostic Aids

The following conditions may cause an intermittent condition:

    • A short circuit between CKT 347 and CKT 348.
    • A short circuit between CKT 347 and CKT 1403.
    • A short circuit between CKT 347 and CKT 1404.
    • A malfunctioning shorting bar on the inflatable restraint steering wheel module connector.
    • A malfunctioning shorting bar on the inflatable restraint steering wheel module coil steering column connector.

When measurements are requested in this table, use J 39200 Digital Multimeter with the correct terminal adapter from J 35616 Connector Test Adapter Kit. When a check for proper connection is requested, refer to Intermittents and Poor Connections . When a wire, connector or terminal repair is requested, use J-38125 Terminal Repair Kit and refer to Wiring Repair .

Test Description

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

  1. This test checks for a short from CKT 1403 to CKT 347.

    2.

  2. This test isolates the malfunction to one side of the inflatable restraint steering wheel module coil yellow 2-way connector.

    3.

  3. This test determines whether the malfunction is due to the inflatable restraint steering wheel module or the module coil.

    4.

  4. This test checks for a short from CKT 347 to CKT 348.

    5.

  5. This test checks for a short from CKT 347 to CKT 1404.

DTC B1122 Driver Deployment Loop Resistance Low

Step

Action

Value(s)

Yes

No

1

Was the SIR Diagnostic System Check performed?

--

Go to Step 2

Go to SIR Diagnostic System Check

2

  1. Turn the ignition switch to the OFF position.
  2. Connect a scan tool to the DLC.
  3. Turn the ignition switch to the RUN position.
  4. Request the SIR DTC display.

Is DTC B1116 also present?

--

Go to Step 3

Go to Step 4

3
  1. Turn the ignition switch to the OFF position.
  2. Disconnect the inflatable restraint steering wheel and IP module yellow 2-way connectors at the base of the steering column and behind the IP compartment.
  3. Repair the short from CKT 347 to CKT 1403.

Have the repairs been completed?

--

Go to Step 13

--

4

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the inflatable restraint steering wheel module yellow 2-way connector at the base of the steering column and behind the IP compartment.
  3. Reconnect the 2-way connector.
  4. Inspect that the CPA is properly installed.
  5. Turn the ignition switch to the RUN position.
  6. Using a scan tool, request the SIR DTC display.

Is DTC B1122 set as a current DTC?

--

Go to Step 5

Go to Step 13

5

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the inflatable restraint steering wheel and IP module yellow 2-way connectors at the base of the steering column and behind the IP compartment.
  3. Connect the J 38715-A Driver/Passenger Load Tool to the harness connectors.
  4. Turn the ignition switch to the RUN position.

Is DTC B1122 set as a current DTC?

--

Go to Step 9

Go to Step 6

6
  1. Turn the ignition switch to the OFF position.
  2. Remove the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .
  3. Disconnect the J 38715-A from the driver 2-way connector.
  4. Connect the 2-way connector at the base of the steering column.
  5. Connect the J 38715-A to the upper inflatable restraint steering wheel module coil connector on the steering column.
  6. Turn the ignition switch to the RUN position.

Is DTC B1122 set as a current DTC?

--

Go to Step 8

Go to Step 7

7
  1. Turn the ignition switch to the OFF position.
  2. Replace the inflatable restraint steering wheel module. Refer to Inflatable Restraint Steering Wheel Module Replacement .

Have the repairs been completed?

--

Go to Step 13

--

8
  1. Turn the ignition switch to the OFF position.
  2. Replace the inflatable restraint steering wheel module coil. Refer to Inflatable Restraint Steering Wheel Module Coil Replacement .

Have the repairs been completed?

--

Go to Step 13

--

9

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the inflatable restraint sensing and diagnostic module (SDM).
  3. Disconnect the J 38715-A .
  4. Using J 39200 DMM, measure the resistance between SDM harness connector terminals 9 and 10.

Is the resistance reading less than the specified value?

OL

Go to Step 10

Go to Step 11

10

Repair a short from CKT 347 to CKT 348.

Have the repairs been completed?

--

Go to Step 13

--

11

Using J 39200 , measure the resistance between SDM harness connector terminals 8 and 10.

Is the resistance reading less than the specified value?

OL

Go to Step 12

Go to Sensing and Diagnostic Module Integrity Check

12

Repair a short from CKT 347 to CKT 1404.

Have the repairs been completed?

--

Go to Step 13

--

13

Reconnect all the SIR system components, make sure all the components are properly mounted.

Have all the SIR components been reconnected and properly mounted?

--

Go to Step 14

--

14

Clear all the SIR DTCs.

Have all the SIR DTCs been cleared?

--

Go to SIR Diagnostic System Check

--