GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 2000 🢒 S/T Isuzu - 2WD 🢒 DTC 🢒 DTC B0091 Active Switch: Wrong State

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

  1. Observes the state of the supplemental restraint IP module Switch, normal state being OFF.

    2.

  2. Tests for a malfunctioning supplemental restraint IP module switch.

    3.

  3. Tests for a malfunctioning supplemental restraint sensing and diagnostic module (SDM).

    4.

  4. Tests for a short in the signal circuits between the supplemental restraint IP module switch and the supplemental restraint sensing and diagnostic module (SDM).

    5.

  5. This step replaces the supplemental restraint sensing and diagnostic module (SDM).

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. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the supplemental restraint IP module switch data parameter in the supplemental restraint sensing and diagnostic module (SDM) data list.

Does the scan tool indicate that the supplemental restraint IP module switch is OFF?

--

Go to Step 3

Go to Step 4

3

  1. Activate the supplemental restraint IP module switch.
  2. With the scan tool, observe the supplemental restraint IP module switch data parameter.

Does the supplemental restraint IP module switch data parameter change state?

--

Go to Diagnostic Aids

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Disconnect the supplemental restraint IP module switch.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the supplemental restraint IP module switch data parameter.

Does the scan tool indicate that the supplemental restraint IP module switch is OFF?

--

Go to Step 7

Go to Step 5

5

Test the passenger SRS enable and disable circuits of the supplemental restraint IP module switch between the IP module switch and the SDM for a short. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 6

6

Inspect for poor connections at the harness connector of the supplemental restraint sensing and diagnostic module (SDM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 8

7

Inspect for poor connections at the harness connector of the supplemental restraint IP module switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 9

8

Replace the supplemental restraint sensing and diagnsotic module (SDM). Refer to Supplemental Restraint Sensing and Diagnostic Module Replacement .

Did you complete the replacement?

--

Go to Step 10

--

9

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

Did you complete the replacement?

--

Go to Step 10

--

10
  1. Reconnect all SRS system 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.

Does the DTC reset?

--

Go to Step 2

System OK