GM Service Manual Online
For 1990-2009 cars only

Object Number: 590451  Size: SF
SIR Component Views
Power/Grounds, Inflator Modules
SIR Handling Caution

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 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

Deployment loop voltage out of range test - Ignition 1 voltage is within the normal operating voltage range.

Deployment loop resistance measurement test:

    • Ignition 1 voltage is within the normal operating voltage range.
    • Driver frontal deployment loop is not shorted to voltage.

Conditions for Setting the DTC

Deployment loop voltage out of range test - Driver frontal high circuit is more than 6 volts for 300 milliseconds.

Deployment loop resistance measurement test - Driver frontal high circuit is less than 2 volts AND driver frontal deployment loop resistance is less than 6 ohms for 300 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

    • You can issue a CLEAR CODES command
    • A history DTC will clear once 255 malfunction free ignition cycles have occurred

Diagnostic Aids

A short to B+ or a short to ground in the inflatable restraint steering wheel module deployment loop can cause an intermittent condition. Inspect the driver frontal high and driver frontal low circuits carefully for cutting or chafing. Wiring pigtail damage requires replacement of the inflatable restraint steering wheel module coil.

Test Description

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

  1. This step checks the inline connector C215.

  2. This step isolates the malfunction to one side of inline connector C215.

  3. This step determines if the inflatable restraint steering wheel module coil or the inflatable restraint steering wheel module is defective.

  4. This step checks to see if there is a short to ground in the driver frontal high circuit in the wiring harness between inline connector C215 and the SDM wiring harness connector.

  5. This step checks to see if there is a short to ground in the driver frontal low circuit in the wiring harness between inline connector C215 and the SDM wiring harness connector.

  6. This step checks to see if there is a short to B+ in the driver frontal high circuit in the wiring harness between inline connector C215 and the SDM wiring harness connector.

  7. This step determines if there is a short to B+ in the driver frontal low circuit in the wiring harness between inline connector C215 and the SDM wiring harness connector or if there is a malfunctioning SDM.

DTC B0024 Driver Frontal Deployment Loop Voltage Out of Range

Step

Action

Value(s)

Yes

No

1

Did you perform the SIR Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - SIR

2

  1. Turn OFF the ignition.
  2. Disconnect the inline connector C215.
  3. Inspect the male and females sides of inline connector C215 for the following conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  4. • Corrosion
    • Damaged terminals
    • Poor connections/terminal tension

Does either the male or female side of inline connector C215 exhibit signs of corrosion, terminal damage, or poor connections?

--

Go to Step 3

Go to Step 4

3

  1. If the female side of the inline connector is damaged, the wiring harness must be replaced.
  2. If the male side of the inline connector is damaged, replace the male side of the connector. Refer to Connector Repairs in Wiring systems.

Did you complete the repair?

--

Go to Step 18

--

4

  1. Reconnect the inline connector C215.
  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 the SIR DTC display.

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 inline connectors C215 and C216.
  3. Install the J 38715-A SIR Driver/Passenger Load Tool to the wiring harness side of inline connectors C215 and C216. Use the J 38715-5 adaptor for inline connector C216 and the J 38715-90 adaptor for inline connector C215.
  4. Turn ON the ignition, with the engine OFF.
  5. Use the scan tool to request the SIR DTC display.

Does the scan tool indicate that this DTC is current?

--

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 SIR Driver/Passenger Load Tool from inline connector C215.
  4. Connect inline connector C215 back together.
  5. Connect the J 38715-A SIR Driver/Passenger Load Tool to the upper inflatable restraint steering wheel module coil connector on the steering column. Use the J 38715-30A adaptor for the upper coil connector.
  6. Turn ON the ignition, with the engine OFF.
  7. Use the scan tool to request the SIR DTC display.

Does the scan tool indicate that this DTC is current?

--

Go to Step 8

Go to Step 7

7

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

Did you complete the replacement?

--

Go to Step 18

--

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 18

--

9

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

Does the resistance measure less than the specified value?

OL

Go to Step 10

Go to Step 11

10

Locate and repair the 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 18

--

11

Use the J 39200 to measure the resistance between the driver frontal low circuit and a known good ground.

Does the resistance measure less than the specified value?

OL

Go to Step 12

Go to Step 13

12

Locate and repair the 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 18

--

13

  1. Turn ON the ignition, with the engine OFF.
  2. Use the J 39200 to measure the voltage between the driver frontal high circuit and a known good ground.

Does the voltage measure less than the specified value?

1 V

Go to Step 15

Go to Step 14

14

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

Did you complete the repair?

--

Go to Step 18

--

15

Use the J 39200 to measure the voltage between the driver frontal low circuit and a known good ground.

Does the voltage measure less than the specified value?

1 V

Go to Step 17

Go to Step 16

16

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

Did you complete the repair?

--

Go to Step 18

--

17

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

Did you complete the replacement?

--

Go to Step 18

--

18

  1. Reconnect all SIR components.
  2. Verify that all components and connectors are properly mounted.
  3. Turn ON the ignition, with the engine OFF.
  4. Use the scan tool in order to clear the DTCs.

Did you complete the action?

--

Go to Diagnostic System Check - SIR

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