GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2007 🢒 Express - AWD 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC B0091

Circuit Description

The inflatable restraint instrument panel module (IPM) disable switch circuit consists of an IPM disable switch, IPM disable switch indicator, IPM disable switch signal circuit, and IPM suppression indicator control circuit. When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. The SDM monitors the voltage levels at the IPM disable switch signal and the IPM suppression indicator control circuits of the SDM to determine the position of the IPM disable switch. If a malfunction is detected, a DTC will be stored in memory.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B0091 Active Switch: Wrong State

Conditions for Running the DTC

Ignition 1 voltage is within the normal operating voltage range.

Conditions for Setting the DTC

The voltage at IPM disable switch signal is low with the IPM disable switch indicator ON and the voltage at IPM suppression indicator control is high for 500 milliseconds.

Action Taken When the DTC Sets
    • The IPM disable switch is defaulted to a calibrated state.
    • The SDM commands ON the AIR BAG indicator via class 2 serial data.
    • The SDM toggles the IPM disable switch AIR BAG indicator ON and OFF every 5 seconds.

Conditions for Clearing the DTC
    • The condition responsible for setting the DTC no longer exists.
    • You issue a scan tool CLEAR DTCs command.
    • A history DTC will clear once 255 malfunction-free ignition cycles have occurred.

Diagnostic Aids

The following can cause an intermittent condition:

A short between the IPM disable switch signal and the IPM suppression indicator control circuits. Refer to Testing for Intermittent Conditions and Poor Connections .

Test Description

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

  1. This step observes the state of the IPM disable switch, normal state being ON.

    2.

  2. This step tests for a malfunctioning IPM disable switch.

    3.

  3. This step tests for a malfunctioning SDM.

    4.

  4. This step tests for a short in the IPM disable switch signal circuit.

    5.

  5. This step tests for a short in the IPM suppression indicator control circuit.

Step

Action

Yes

No

Schematic Reference: SIR Schematics

Connector End View Reference: SIR Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Turn OFF the ignition.
  2. Disconnect the instrument panel module (IPM) disable switch. Refer to Inflatable Restraint Instrument Panel Module Disable Switch Replacement .
  3. Inspect the IPM disable switch connector for corrosion or damage. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 3

3

  1. Reconnect the IPM disable switch connector.
  2. Turn the IPM disable switch to the OFF position.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the I/P module disable switch (active switch) data parameter in the inflatable restraint sensing and diagnostic module (SDM) inputs list.

Does the scan tool indicate that the I/P module disable switch (active switch) is DISABLED?

Go to Step 4

Go to Step 5

4

  1. Turn the IPM disable switch to the ON position.
  2. With a scan tool, observe the I/P module disable switch (active switch) data parameter.

Does the I/P module disable switch (active switch) data parameter change state?

Go to Diagnostic Aids

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Disconnect the IPM disable switch. Refer to Inflatable Restraint Instrument Panel Module Disable Switch Replacement .
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the I/P module disable switch (active switch) data parameter.

Does the scan tool indicate that the I/P module disable switch (active switch) is DISABLED?

Go to Step 10

Go to Step 6

6

Test the IPM disable switch signal circuit for a short. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 7

7

Test the IPM suppression indicator control circuit for a short. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 8

8
  1. Turn OFF the ignition.
  2. Disconnect the SDM connector. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  3. Inspect the SDM connector for corrosion or damage. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 9

9

Replace the SDM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 11

--

10

Replace the IPM disable switch. Refer to Inflatable Restraint Instrument Panel Module Disable Switch Replacement .

Did you complete the replacement?

Go to Step 11

--

11
  1. Reconnect all SIR system components.
  2. Verify that all components, connectors, and connector position assurances (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