GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 2000 🢒 S/T Isuzu - 4WD 🢒 Restraints 🢒 SRS 🢒 DTC B0090 Active Switch Voltage Out of Range

Object Number: 391968 Size: MF
SRS Components
SRS Schematic
SRS Schematic Icons
SRS Schematic Icons
SRS Schematic Icons

Circuit Description

When you first turn the ignition switch to the RUN position, the supplemental restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. The SDM monitors the voltage levels at the passenger frontal SRS enable and disable terminals of the SDM to determine the position of the supplemental restraint IP module switch. The SDM then 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
    • Ignition 1 voltage is within the normal operating voltage range.
    • Passenger frontal deployment loop is not shorted to voltage.

Conditions for Setting the DTC
    • The voltage detected at passenger frontal SRS enable terminal and passenger frontal SRS disable terminal are less than 1.0 volt when the AIR BAG ON lamp is commanded ON.
    • The voltage detected at passenger frontal SRS enable terminal and passenger frontal SRS disable terminal are greater than 4.0 volts when the AIR BAG ON lamp is commanded OFF.
    • The voltage detected at passenger frontal SRS enable terminal and passenger frontal SRS disable terminal are greater than 1.0 volt when the AIR BAG OFF lamp is commanded ON.

Action Taken When the DTC Sets
    • The supplemental restraint IP module switch is defaulted to the disabled state.
    • The SDM commands ON the AIR BAG warning lamp via Class 2 serial data.
    • The SDM attempts to illuminate the supplemental restraint IP module switch AIR BAG OFF lamp.

Conditions for Clearing the DTC
    • The supplemental restraint IP module switch AIR BAG lamp is OFF, and the voltage at passenger frontal SRS enable terminal and passenger frontal SRS disable terminal are in opposite states for 300 milliseconds.
    • You issue a scan tool CLEAR CODES command.
    • A history DTC will clear once 255 malfunction free ignition cycles have occurred.

When the SDM detects that no DTCs are present, the SDM commands the AIR BAG warning lamp OFF.

Diagnostic Aids

The following can cause an intermittent condition:

    • A short between the the passenger frontal SRS enable and the passenger frontal SRS disable circuits.
    • Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

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

  1. Test determines if the AIR BAG ON lamp illuminates when the supplemental restraint IP module switch is in the ON position.

    2.

  2. Tests for a poor connection at the supplemental restraint IP module switch harness connector.

    3.

  3. Test determines whether the malfunction is in the supplemental restraint IP module switch ground circuit.

    4.

  4. Test determines whether the malfunction is in the power feed circuit between the fuse block and the supplemental restraint IP module switch.

    5.

  5. Tests for proper contact or corrosion of the supplemental restraint sensing and diagnostic module (SDM) harness connector.

    6.

  6. Tests for an open or high resistance in the passenger SRS enable circuit.

    7.

  7. Tests for a short to ground in the passenger SRS enable circuit.

    8.

  8. Tests for a short to voltage in the passenger SRS disable circuit.

    9.

  9. Tests for a short between the passenger SRS enable and disable circuits.

    10.

  10. Tests for a short to voltage in the passenger SRS disable circuit.

    11.

  11. Tests for a short to voltage in the passenger SRS enable circuit.

    12.

  12. Tests for an open or high resistance in the passenger SRS disable circuit.

    13.

  13. Tests for a short to ground in the passenger SRS disable circuit.

Step

Action

Value(s)

Yes

No

1

Did you perform the A Diagnostic System Check-SRS?

--

Go to Step 2

Go to Diagnostic System Check - SRS

2

  1. Turn OFF the ignition.
  2. Turn the supplemental restraint IP module switch to the ON position.
  3. Turn ON the ignition, with the engine OFF.

Does the AIR BAG ON lamp illuminate in the IP module switch?

--

Go to Step 10

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Remove the supplemental restraint IP module switch from the instrument panel cluster (IPC). Refer to Supplemental Restraint Instrument Panel Module Disable Switch Replacement .
  3. Inspect the supplemental restraint IP module switch wiring harness connector for the following conditions:
    • Corrosion
    • Terminal damage
    • Poor connections/terminal tension

Does the connector exhibit any signs of corrosion, terminal damage, or poor connections?

--

Go to Step 4

Go to Step 5

4

Repair or replace the the supplemental restraint IP module switch harness connector. Refer to Connector Repairs in Wiring Systems.

Did you complete the replacement?

--

Go to Step 33

--

5

Inspect the supplemental restraint IP module switch terminals for the following conditions:

    • Corrosion
    • Terminal damage

Do the terminals exhibit any signs of corrosion or terminal damage?

--

Go to Step 32

Go to Step 6

6

  1. Disable the SRS system. Refer to Disabling the SRS .
  2. Using DMM measure the resistance of the ground circuit from the supplemental restraint IP module switch harness connector terminal to a known good ground. Refer to Circuit Testing in Wiring Systems.

Does the resistance measure greater than the specified value?

5 ohms

Go to Step 7

Go to Step 8

7

Locate and repair an open or high resistance in the supplemental restraint IP module switch ground circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 33

--

8

  1. Install the SIR Fuse.
  2. Turn ON the ignition, with the engine OFF.
  3. Using the DMM measure the voltage between the supplemental restraint IP module switch harness connector terminal B and a known good ground. Refer to Circuit Testing in Wiring Systems.

Does the voltage measure greater than the specified value?

1 V

Go to Step 10

Go to Step 9

9

Locate and repair an open or high resistance in the supplemental restraint IP module switch power feed circuit between the fuse block and the IP module switch. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 33

--

10
  1. Turn OFF the ignition.
  2. Install a scan tool.
  3. Turn the supplemental restraint IP module switch to the ON position.
  4. Turn ON the ignition, with the engine OFF.
  5. Use the scan tool to request the SRS data display.

Does the active switch show the specified state?

Enabled

Go to Step 20

Go to Step 11

11

  1. Turn OFF the ignition.
  2. Remove the SIR Fuse.
  3. Disconnect the supplemental restraint sensing and dignostic module (SDM) harness connector. Refer to Supplemental Restraint Sensing and Diagnostic Module Replacement .
  4. Inspect the SDM harness connector for the following conditions:
    5. • Corrosion
    • Terminal damage
    • Poor connections/terminal tension

Does the connector exhibit any signs of corrosion, terminal damage, or poor connections?

--

Go to Step 21

Go to Step 12

12

Using DMM measure the resistance of the passenger SRS enable circuit between the supplemental restraint IP module switch harness connector and the SDM harness connector.

Does the resistance measure greater than the specified value?

5 ohms

Go to Step 13

Go to Step 14

13

Locate and repair an open or high resistance in the passenger SRS enable circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 33

--

14

Using DMM measure the resistance of the passenger SRS enable circuit from the supplemental restraint IP module harness connector to a known good ground. Refer to Circuit Testing in Wiring Systems.

Does the resistance measure less than the specified value?

OL

Go to Step 15

Go to Step 16

15

Locate and repair a short to ground in the passenger SRS enable circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 33

--

16

  1. Reconnect the supplemental restraint IP module switch harness connector. Refer to Supplemental Restraint Instrument Panel Module Disable Switch Replacement .
  2. Install the SIR Fuse.
  3. Turn ON the ignition, with the engine OFF.
  4. Turn the supplemental restraint IP module switch to the OFF position.
  5. Using DMM measure the voltage of the passenger SRS disable circuit between the supplemental restraint IP module switch harness connector and a known good ground. Refer to Circuit Testing in Wiring Systems.

Does the voltage measure greater than the specified value?

1 V

Go to Step 17

Go to Step 18

17

Locate and repair a short to voltage in the passenger SRS disable circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 33

--

18

  1. Turn OFF the ignition.
  2. Using DMM measure the resistance between the passenger SRS enable and the passneger SRS disable circuits at the supplemental restraint IP module harness connector. Refer to Circuit Testing in Wiring Systems.

Does the resistance measure less than the specified value?

OL

Go to Step 19

Go to Step 32

19

Locate and repair a short between the passenger SRS enable and Passenger SRS disable circuits. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 33

--

20
  1. Turn OFF the ignition.
  2. Disable the SRS system. Refer to Disabling the SRS
  3. Disconnect the supplemental restraint sensing and diagnostic module (SDM) harness connector. Refer to Supplemental Restraint Sensing and Diagnostic Module Replacement .
  4. Inspect the SDM harness connector for the following conditions:
    • Corrosion
    • Terminal damage
    • Poor connections/terminal tension

Does the connector exhibit any signs of corrosion, terminal damage, or poor connections?

--

Go to Step 21

Go to Step 22

21

Repair or replace the supplemental restraint sensing and diagnostic module (SDM) harness connector. Refer to Connector Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 33

--

22
  1. Turn OFF the ignition.
  2. Remove the supplemental restraint IP module switch from the instrument panel cluster (IPC). Refer to Supplemental Restraint Instrument Panel Module Disable Switch Replacement .
  3. Inspect the supplemental restraint IP module switch wiring harness connector for the following conditions:
    • Corrosion
    • Terminal damage
    • Poor connections/terminal tension

Does the connector exhibit any signs of corrosion, terminal damage, or poor connections?

--

Go to Step 23

Go to Step 24

23

Repair or replace the supplemental restraint IP module switch harness connector. Refer to Connector Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 33

--

24

  1. Reconnect the supplemental restraint sensing and diagnostic module (SDM) harness connector. Refer to Supplemental Restraint Sensing and Diagnostic Module Replacement .
  2. Turn ON the ignition, with the engine OFF.
  3. Using DMM measure the voltage of the passenger SRS disable circuit between the supplemental restraint IP module switch harness connector and a known good ground. Refer to Circuit Testing in Wiring Systems.

Does the voltage measure greater than the specified value?

1 V

Go to Step 25

Go to Step 26

25

Locate and repair a short to voltage in the passenger SRS disable circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 33

--

26

Using DMM measure the voltage of the passenger SRS enable circuit between the the supplemental restraint IP module switch harness connector and a known good ground. Refer to Circuit Testing in Wiring Systems.

Does the voltage measure greater than the specified value?

1 V

Go to Step 27

Go to Step 28

27

Locate and repair a short to voltage in the passenger SRS enable circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 33

--

28

  1. Turn OFF the ignition.
  2. Using DMM measure the resistance of the passenger SRS disable circuit between the supplemental restraint IP module harness connector and the supplemental restraint sensing and diagnostic module (SDM) harness connector. Refer to Circuit Testing in Wiring Systems.

Does the resistance measure greater than the specified value?

5 ohms

Go to Step 29

Go to Step 30

29

Locate and repair an open or high resistance in the passenger SRS disable circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 33

--

30

Using DMM measure the resistance between the passenger SRS disable circuit and the ground circuit at the supplemental restraint IP module switch harness connector. Refer to Circuit Testing in Wiring Systems.

Does the resistance measure less than the specified value?

OL

Go to Step 31

Go to Step 32

31

Locate and repair a short to ground in the passenger SRS disable circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 33

--

32

Replace the supplemental restraint IP module switch. Refer to Supplemental Restraint Instrument Panel Module Disable Switch Replacement .

Did you complete the repair?

--

Go to Step 33

--

33
  1. Reconnect all SRS system components. Refer to Enabling the SRS .
  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.

Does the DTC reset?

--

Go to Step 2

System OK