GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1997 🢒 Jimmy - 4WD 🢒 DTC 🢒 DTC B1024 Driver Initiator Circuit Voltage Low

Object Number: 39360 Size: LF

Circuit Description

During normal, non-deployment operation of the SIR system, a small amount of current flows through the driver deployment loop. The diagnostic resistors within the inflatable restraint arming sensor and the inflatable restraint discriminating sensors, along with the resistance of the inflatable restraint steering wheel inflator module cause voltage drops within the deployment loop. The inflatable restraint Diagnostic Energy Reserve Module (DERM) monitors the voltage at the Driver Side Low terminal B8 to detect shorts or opens within the deployment loop. DTC B1024 sets when the DERM measures the voltage at terminal B8 below a specified percentage of Driver 36 VLR for 500 milliseconds.

Conditions for Setting the DTC

The DTC clears when the DERM measures Driver Side Low terminal B8 voltage below a specified percentage of Driver 36 VLR for 500 milliseconds during Continuous Monitoring tests.

Action Taken When the DTC Sets

The DERM turns on the AIR BAG warning lamp and sets a diagnostic trouble code.

Conditions for Clearing the DTC

The DTC clears when the DERM measures Driver Side Low terminal B8 voltage within a specified percentage of Driver 36 VLR for 500 milliseconds during Continuous Monitoring tests.

Diagnostic Aids

An intermittent condition is likely to be caused by a poor connection at any of the following locations:

    • The DERM terminal A4
    •  The inflatable restraint arming sensor terminal B
    • The inflatable restraint arming sensor terminal D
    • The inflatable restraint arming sensor jumper harness electrical connector terminal B
    • The inflatable restraint arming sensor jumper harness electrical connector terminal or D

Water intrusion in either of the inflatable restraint discriminating sensors, an open in CKT 347 or a short to ground on CKT 347, CKT 348, or CKT 349 may also cause an intermittent condition.

Refer to DTC B1025 Driver Initiator CKT Short to Ignition in order to diagnose a possible short to B+. When the malfunction occurs during an ignition cycle DTC B1024 will set. DTC B1025 will set, and DTC B1024 will be moved to a history file, if this malfunction is present at the beginning of the next ignition cycle.

Test Description

Refer to step numbers on the diagnostic table.

  1. Start at the SIR Diagnostic System Check for all diagnosis.

    2.

  2. This test determines whether the malfunction is in the steering column circuitry.

    3.

  3. This test determines whether the malfunction is due to a component or the wiring.

    4.

  4. This test checks for increased resistance of the inflatable restraint arming sensor.

    5.

  5. This test checks for a partial short inside the LH forward inflatable restraint discriminating sensor.

    6.

  6. This test checks for a partial short inside the RH forward inflatable restraint discriminating sensor.

    7.

  7. This test checks for an open in circuit 347.

    8.

  8. This test determines where the open in circuit 347 is located.

    9.

  9. This test checks for a short from the Driver Side High circuit-to-ground.

    10.

  10. This test checks for a short from the Driver Side Low circuit-to-ground.

    11.

  11. This test checks for a short from the inflatable restraint discriminating sensor interconnect circuit-to-ground.

  12. This test checks short inside the LH forward inflatable restraint discriminating sensor

    13.

  13. This test checks short inside the RH forward inflatable restraint discriminating sensor

When measurements are requested in this table, use J 39200 Digital Multimeter with correct terminal adapter from J 35616 Connector Test Adapter Kit. When a check for proper connection is requested, refer to Intermittents and Poor Connections in Section 8A4. When a wire, connector or terminal repair is requested, use J-38125 Terminal Repair Kit and refer to Wiring Repair.

DTC B1024- Driver Initiator Circuit Voltage Low

Step

Action

Value

Yes

No

1

Was the SIR Diagnostic System Check performed?

--

Go to Step 2

Go to SIR Diagnostic System Check

2

  1. Turn OFF the ignition switch.
  2. Disconnect the yellow 2-way electrical connector C214 at the base of the steering column.
  3. Connect the J 38715-A SIR Driver/Passenger Load Tool to harness side of the yellow 2-way electrical connector at the base of the steering column.
  4. Turn ON the ignition switch.

Is DTC B1024 current?

--

Go to Step 4

Go to Step 3

3
  1. Turn OFF the ignition switch.
  2. Disconnect the J 38715-A.
  3. Remove the inflatable restraint steering wheel inflator module from the steering wheel. Refer to Steering Column in Section 3F.
  4. Remove the inflatable restraint steering wheel module coil. Refer to Steering Column Unit Repair in Section 3F4 or 3F5.
  5. Determine the cause of the shorted circuit and repair.
  6. Replace the inflatable restraint steering wheel module coil. Refer to Steering Column Unit Repair in Section 3F4 or 3F5.

Has the inflatable restraint steering wheel module coil been replaced?

--

Go to Step 37

--

4

Using the Scan Tool SIR Data List function select Driver LO.

Is the voltage displayed less than the value specified?

1 V

Go to Step 22

Go to Step 5

5
  1. Turn off the ignition switch.
  2. Disconnect the DERM.
  3. Check for proper connection to the DERM at terminal A4.

Is the DERM electrical harness connector terminal A4 damaged or corroded?

--

Go to Step 6

Go to Step 8

6

Repair the DERM electrical harness connector.

Has the connector been repaired?

--

Go to Step 7

--

7

Check for proper connection to the DERM at terminal A4.

Are the DERM terminals damaged or corroded?

--

Go to Step 9

Go to Step 37

8

Check for proper connection to the DERM at terminal A4.

Are the DERM terminals damaged or corroded?

--

Go to Step 9

Go to Step 10

9

Replace the DERM. Refer to Inflatable Restraint Diagnostic Energy Reserve Module

Has the DERM been replaced?

--

Go to Step 37

--

10

  1. Disconnect the inflatable restraint arming sensor jumper harness electrical connector C110.
  2. Check the inflatable restraint arming sensor jumper harness electrical connector for proper connection at terminals B and D.

Is the connector damaged or corroded?

--

Go to Step 11

Go to Step 12

11

Repair the inflatable restraint arming sensor jumper harness connector.

Has the connector been repaired?

--

Go to Step 37

--

12
  1. Disconnect the inflatable restraint arming sensor.
  2. Check for proper connection to the inflatable restraint arming sensor at terminals B and D.

Is the inflatable restraint arming sensor electrical harness connector damaged or corroded?

--

Go to Step 13

Go to Step 15

13

Repair the inflatable restraint arming sensor electrical harness connector.

Has the connector been repaired?

--

Go Step 14

--

14

Check for proper connection to the inflatable restraint arming sensor at terminals B and D.

Are the inflatable restraint arming sensor terminals damaged or corroded?

--

Go to Step 16

Go to Step 37

15

Check for proper connection to the inflatable restraint arming sensor at terminals B and D.

Are the inflatable restraint arming sensor terminals damaged or corroded?

--

Go to Step 16

Go to Step 17

16

Replace the inflatable restraint arming sensor. Refer to Inflatable Restraint Arming Sensor .

Is the repair complete?

--

Go to Step 37

--

17

Measure the resistance of the inflatable restraint arming sensor from terminal C to terminal D.

Is the resistance more than the value specified?

7.67 kohms

Go to Step 16

Go to Step 18

18

  1. Disconnect the inflatable restraint discriminating sensor intermediate harness electrical connector C109.
  2. Measure the resistance on Discriminating Sensor Intermediate harness electrical connector C109 (engine harness side). from terminal A to terminal B.

Is the resistance less than the value specified?

8.36 kohms

Go to Step 19

Go to Step 20

19

Replace the LH forward inflatable restraint discriminating sensor. Refer to Inflatable Restraint Front End Discriminating Sensor .

Has the LH forward inflatable restraint discriminating sensor been replaced?

--

Go to Step 37

--

20

Measure the resistance on the inflatable restraint discriminating sensor intermediate harness electrical connector C109 (engine harness side) from terminal A to terminal C.

Is the resistance less than the value specified?

8.36 kohms

Go to Step 21

Go to Integrity Check

21

Replace the RH forward inflatable restraint discriminating sensor. Refer to Inflatable Restraint Front End Discriminating Sensor .

Has the RH forward inflatable restraint discriminating sensor been replaced?

--

Go to Step 37

--

22

  1. Turn OFF the ignition switch.
  2. Disconnect the DERM.
  3. Disconnect the inflatable restraint arming sensor.
  4. Check for proper connection on the inflatable restraint arming sensor electrical harness connector terminal D.

Is the inflatable restraint arming sensor electrical harness connector damaged or corroded?

--

Go to Step 13

Go to Step 23

23

Check for proper connection on the inflatable restraint arming sensor at terminal D.

Are the inflatable restraint arming sensor terminals damaged or corroded?

--

Go to Step 16

Go to Step 24

24

  1. Disconnect J 38715-A SIR Driver/Passenger Load Tool.
  2. Measure the resistance from the inflatable restraint arming sensor electrical harness connector terminal D to harness side of the yellow 2-way connector at the base of the steering column terminal A.

Is the resistance less than the value specified?

5 ohms

Go to Step 29

Go to Step 25

25

  1. Disconnect the inflatable restraint arming sensor jumper harness electrical connector C110.
  2. Check for proper connection at inflatable restraint arming sensor jumper harness electrical connector at the terminal D.

Is the connector damaged or corroded?

--

Go to Step 11

Go to Step 26

26

Measure the resistance of circuit 347 from the harness side of the yellow 2-way electrical connector at the base of the steering column terminal A to the bulk head side of the inflatable restraint arming sensor jumper harness electrical connector C110 terminal D.

Is the resistance less than the value specified?

5 ohms

Go to Step 27

Go to Step 28

27

Repair the open in circuit 347 in the inflatable restraint arming sensor jumper harness.

Has the open circuit been repaired?

--

Go to Step 37

--

28

Repair the short in circuit 347 in the SIR wiring harness.

Has the open circuit been repaired?

--

Go to Step 37

--

29

Measure the resistance on the DERM electrical harness connector from terminal B9 to terminal A1 (ground).

Does the J 39200 display OL (infinite)?

--

Go to Step 31

Go to Step 30

30

Repair the short from circuit 347 to ground.

Has the short-to-ground be repaired?

--

Go to Step 37

--

31

  1. Disconnect the LH forward inflatable restraint discriminating sensor.
  2. Measure the resistance on the DERM electrical harness connector from terminal B9 to A1 (ground).

Does J 39200 display OL (infinite)?

--

Go to Step 33

Go to Step 32

32

Repair the short from circuit 348 to ground.

Has the short-to-ground been repaired?

--

Go to Step 37

--

33

  1. Disconnect the RH forward inflatable restraint discriminating sensor
  2. Measure the resistance on the LH forward inflatable restraint discriminating sensor electrical harness connector from terminal B to terminal C (ground).

Does J 39200 display OL (infinite)?

--

Go to Step 35

Go to Step 34

34

Repair the short from circuit 349 to ground.

Has the short-to-ground been repaired?

--

Go to Step 37

--

35

  1. Reconnect the RH forward inflatable restraint discriminating sensor.
  2. Measure the resistance of the LH forward inflatable restraint discriminating sensor from terminal A to terminal C.

Is the resistance less than the value specified?

8.36 kohms

Go to Step 19

Go to Step 36

36

Measure the resistance on the LH forward inflatable restraint discriminating sensor electrical harness connector from terminal B to terminal C.

Is the resistance less than the value specified?

8.36 kohms

Go to Step 21

Go to Integrity Check

37
  1. Reconnect all the SIR system components.
  2. Ensure that the components are properly mounted.

Have all the SIR system components been reconnected and properly mounted?

--

Go to Step 38

--

38

Clear the SIR Diagnostic Trouble Codes.

Have the SIR Diagnostic Trouble Codes been cleared?

--

Go to SIR Diagnostic System Check

--