GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2000 🢒 Eldorado 🢒 Restraints 🢒 SIR 🢒 DTC B1124 Driver/Pass. Deploy. Loop Short to GND

Object Number: 585658 Size: MF
SIR Components
SIR Schematics
SIR Handling Caution
Handling ESD Sensitive Parts Notice
SIR Schematic Icons
SIR Schematic Icons

Circuit Description

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 measures the ignition positive voltage in order to ensure that the voltage is within the respective normal voltage range. The SDM proceeds with the deployment loop continuity test. During the deployment loop continuity test, the SDM measures the voltage difference between the high and low deployment circuits.

Conditions for Running the DTC
    • Ignition 1 voltage is within the normal operating voltage range.
    • Driver or passenger frontal deployment loops are not shorted to voltage.
    • Driver or passenger frontal deployment loops are not shorted to ground.
    • Driver or passenger frontal deployment loops are not open.

Conditions for Setting the DTC

The driver or passenger frontal deployment loops are not less than 2.2 volts 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 driver or passenger frontal deployment loops are greater than or equal to 2.2 volts for 500 milliseconds.
    • You can issue a CLEAR CODES command
    • A history DTC will clear once 250 malfunction free ignition cycles have occurred

Diagnostic Aids
    • The SDM wiring harness connector.
    • The wire to terminal connection, open, or short in the driver frontal high and/or low circuit.
    • The wire to terminal connection, open, or short in the passenger frontal high and/or low circuit.

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

Noting the value of the driver senselo and the passenger senselo during diagnosis can be helpful in determining if an intermittent condition exists. An intermittent open in the inflatable restraint steering wheel module coil could also set this DTC. In order to test for a bad inflatable restraint steering wheel module coil, monitor the driver senselo while you turn the steering wheel back and forth when you turn ON the ignition switch. If the driver senselo changes while you are turning the steering wheel, a malfunction in the inflatable restraint steering wheel module coil is likely.

Test Description

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

  1. This step checks the in-line connectors for both front inflator modules.

    2.

  2. This step test for the proper operation of inflatable restraint steering wheel module coil and/or inflatable restraint steering wheel inflator module.

    3.

  3. This step test for the proper operation of inflatable restraint IP/passenger inflator module.

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 in-line connector that connect steering wheel restraint module coil to vehicle wiring harness.
  3. Disconnect inflatable restraint IP/passenger inflator module in-line connector.
  4. Inspect all the wiring harness connectors for the following conditions:
    5. • Corrosion
    • Terminal damaged
    • Poor connections/terminal tension
  5. If any of the above conditions are found refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Does connector exhibits any signs of corrosion, terminal damaged, or poor connections?

--

Go to Step 3

Go to Step 4

3
  1. Replace the wiring harness side of in-line connector. Refer to Connector Repairs in Wiring Systems.
  2. If steering wheel restraint module coil exhibits any of the above conditions, the module must be replace. Refer to Inflatable Restraint Steering Wheel Module Coil Replacement .

Did you complete the replacement?

--

Go to Step 19

--

4
  1. Reconnect both inflatable restraint inflator modules in-line connectors.
  2. Verify that the connector position assurance (CPA) is properly installed.
  3. Turn ON the ignition, with the engine OFF.
  4. 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 that connect steering wheel restraint module coil to vehicle wiring harness.
  3. Install the J 38715-A SIR Load Tool to the wiring harness side of 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 data List display, read the driver frontal low voltage DRIVER SENSELO.

Does the scan tool indicate that DRIVER SENSELO is less than the specified value?

2.2 V

Go to Step 9

Go to Step 6

6

  1. Turn OFF the ignition.
  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 in-line connector.
  4. Connect the driver in-line connector.
  5. Install the J 38715-A to the upper inflatable restraint steering wheel module coil connector.
  6. Turn ON the ignition, with the engine OFF.
  7. Use the scan tool to request SIR data List display, read the driver frontal low voltage DRIVER SENSELO.

Does the scan tool indicate that DRIVER SENSELO is less than the specified value?

2.2 V

Go to Step 8

Go to Step 7

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

Did you complete the replacement?

--

Go to Step 19

--

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

Did you complete the replacement?

--

Go to Step 19

--

9
  1. Turn OFF the ignition.
  2. Disconnect the inflatable restraint IP module connector.
  3. Disconnect the inflatable restraint sensing and diagnostic module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  4. Disconnect the J 38715-A .
  5. Use the J 39200 DMM and measure the resistance between the driver frontal high circuit and the SDM ground on the SDM harness connector.

Does the resistance measure less than the specified value?

OL

Go to Step 10

Go to Step 11

10

Locate and repair short to ground in the driver frontal high circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 19

--

11

Use the J 39200 and measure the resistance between the driver frontal low circuit and the SDM ground on the SDM harness connector.

Does the resistance measure less than the specified value?

OL

Go to Step 12

Go to Step 13

12

Locate and repair short to ground in the driver frontal low circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 19

--

13

  1. Turn OFF the ignition.
  2. Disconnect the inflatabIe restraint IP module yellow connector behind the IP compartment. Leave the inflatable restraint steering wheel module connected.
  3. Install the J 38715-A SIR Load Tool to the wiring harness side of in-line connector. Use appropriate connector adaptors where necessary.
  4. Reconnect the SDM connector.
  5. Turn ON the ignition, with the engine OFF.
  6. Use the scan tool to request SIR data list display.
  7. Read the passenger low voltage PASS. SENSELO.

Does the scan tool indicate that PASS. SENSELO is less than the specified value?

2.2 V

Go to Step 15

Go to Step 14

14
  1. Turn OFF the ignition.
  2. Replace the inflatable restraint passenger inflator module. Refer to Inflatable Restraint Instrument Panel Module Replacement .

Did you complete the replacement?

--

Go to Step 19

--

15
  1. Turn OFF the ignition.
  2. Disconnect the SDM.
  3. Disconnect the J 38715-A .
  4. Use the J 39200 and measure the resistance between the passenger frontal high circuit and SDM ground on the SDM harness connector.

Does the resistance measure less than the specified value?

OL

Go to Step 16

Go to Step 17

16

Locate and repair short to ground in the passenger frontal high circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 19

--

17

Use the J 39200 and measure the resistance between the passenger frontal low circuit and the SDM ground on the SDM harness connector.

Does the resistance measure less than the specified value?

OL

Go to Step 18

Go to Step 19

18

Locate and repair short to ground in the passenger frontal low circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 19

--

19
  1. Reconnect all SIR components.
  2. Verify that all components, connectors and CPAs are properly mounted.
  3. Turn ON the ignition, with the engine OFF.
  4. Verify that DRIVER SENSELO and PASS. SENSELO are more than the specified value.

Does the scan tool indicate that DRIVER and/or PASSENGER SENSELO is greater than the specified value?

2.2 V

Go to Step 21

Go to Step 20

20

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

Did you complete the replacement?

--

Go to Step 21

--

21
  1. Reconnect all SIR components.
  2. Verify that all 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?

--

Go to Diagnostic System Check - SIR

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