GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Vivant 🢒 Preface 🢒 Cautions and Notices 🢒 DTC 024

Circuit Description

When the ignition switch is turned to ON, the sensing and diagnostic module (SDM) will perform tests to diagnose critical malfunctions within itself. Upon passing these tests, ignition and deployment loop voltages are measured to ensure that they are within their respective normal voltage ranges. The SDM monitors the voltages at the driver low, terminal A7, and passenger low, terminal A8, to detect shorts to ground or voltage in the deployment loops.

Conditions for Setting the DTC
    • Voltage at driver high is higher than 6 volts for 500 milliseconds.
    • Voltage at driver high is less than 2 volts and the resistance of driver deployment loop is less than 4.5 ohms for 500 milliseconds.
    • Ignition is within the normal operating voltage range.

Action Taken When the DTC Sets
    • The SDM will turn on the AIRBAG indicator and set a diagnostic trouble code 24.
    • The SDM will disable he driver deployment loop resistance test.

Conditions for Clearing the DTC
    • Voltage at driver high is less than or equal to 6 volts for 500 milliseconds.
    • Voltage at driver high is higher than or equal to 2 volts and the resistance of driver deployment loop is less than 4.5 ohms for 500 milliseconds.
    • Turn OFF the ignition switch.
    • The scan tool CLEAR CODES command is received.

Diagnostic Aids

Important:  A careful inspection of the circuits and components indicated on the DTC 24 chart is essential to ensure that the replacement SDM will not be damaged. When DTC 24 has been set, it is necessary to replace the SDM.

Important: A careful inspection of the circuits and components indicated on the DTC 24 chart is essential to ensure that the replacement SDM will not be damaged. When DTC 24 has been set, it is necessary to replace the SDM.

Carefully inspect the wires in the driver loop for cutting or chafing.

Step

Action

Values

Yes

No

1

Perform the Diagnostic System Check - SIR.

Is the Diagnostic System Check - SIR complete?

--

Go to Step 2

Go to Diagnostic System Check - SIR

2
  1. Turn OFF the ignition and remove the key.
  2. Disconnect passenger airbags, the yellow clock spring connector on the steering column and connector C221.
  3. Visually inspect the driver airbag circuit and connectors, especially at the SDM.

Is there any evidence of rubbing, damage, or chafing?

--

Go to Step 3

Go to Step 4

3
  1. Repair the damaged wires or connectors.
  2. Replace the SDM. The arrow must be pointing toward the front of the vehicle. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  3. Connect all SIR components.

--

Go to Diagnostic System Check - SIR

--

4
  1. Disconnect the yellow clock spring connector on the steering column if it was not previously disconnected.
  2. At the SDM connector, use an ohmmeter to check for a short between terminal A6, driver high, and terminal A18, ground.

Refer to Diagnostic Illustration 12 in SIR Diagnostic Illustrations .

Is the resistance equal to the specified value?

∞

Go to Step 6

Go to Step 5

5
  1. Repair the short to ground in the driver high circuit between the clock spring connector and the SDM.
  2. Replace the SDM. The arrow must be pointing toward the front of the vehicle.
  3. Connect all SIR components.

Did you complete the repair?

--

Go to Diagnostic System Check - SIR

--

6

Measure the resistance at the SDM connector between terminal A7, drive low, and terminal A18, ground.

Refer to Diagnostic Illustration 13 in SIR Diagnostic Illustrations .

∞

Go to Step 8

Go to Step 7

7
  1. Repair the short to ground in the driver low circuit between the SDM and the clock spring connector.
  2. Replace the SDM. The arrow must be pointing toward the front of the vehicle.
  3. Connect all the SIR components.

Did you complete the repair?

--

Go to Diagnostic System Check - SIR

--

8
  1. Temporarily remove the driver airbag.
  2. Connect the yellow clock spring connector on the steering column.
  3. At the SDM connector, use an ohmmeter to check for a short between terminal A6, driver high, and terminal A18, ground.

Refer to Diagnostic Illustration 12 in SIR Diagnostic Illustrations .

Is the resistance equal to the specified value?

∞

Go to Step 9

Go to Step 10

9
  1. Turn ON the ignition.
  2. Using a digital multimeter, measure the voltage between terminal A6, driver high and terminal A18, ground.

Refer to Diagnostic Illustration 14 in SIR Diagnostic Illustrations .

Is the voltage below the value specified?

5.0 V

Go to Step 11

Go to Step 10

10
  1. Turn OFF the ignition and remove the key.
  2. Turn the steering wheel to the straight-ahead position.
  3. Disconnect the yellow clock spring connector on the steering column.
  4. Replace the clock spring. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  5. Replace the SDM. The arrow must be pointing toward the front of the vehicle.
  6. Connect all SIR components.

Did you complete the repair?

--

Go to Diagnostic System Check - SIR

--

11

Measure the resistance at the SDM connector between terminal A7, drive low, and terminal A18, ground.

Refer to Diagnostic Illustration 13 in SIR Diagnostic Illustrations .

Is the resistance equal to the specified value?

∞

Go to Step 12

Go to Step 10

12
  1. Turn ON the ignition.
  2. Measure the voltage at the SDM connector between terminal A7, drive low and terminal A18, ground.

Refer to Diagnostic Illustration 15 in SIR Diagnostic Illustrations .

Is the voltage below the specified value?

5.0 V

Go to Step 13

Go to Step 10

13
  1. Disconnect the yellow clock spring connector on the steering column.
  2. Replace the driver airbag. Refer to Inflatable Restraint Steering Wheel Module Replacement .
  3. Replace the SDM. The arrow must be pointing toward the front of the vehicle.
  4. Connect all SIR components.

Did you complete the repair?

--

Go to Diagnostic System Check - SIR

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