Hummer H2. Manual - part 2062

DTC B0091 

Circuit Description 

The inflatable restraint I/P module disable switch circuit consists of an I/P module disable switch, I/P module 
disable switch indicator, I/P module disable switch signal circuit, and I/P module 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 I/P module 
disable switch signal and the I/P module suppression indicator control circuits of the SDM to determine the 
position of the I/P module disable switch. If a malfunction is detected, a DTC will be stored. 

Conditions for Running the DTC 

Ignition 1 voltage is within the normal operating voltage range. 

Conditions for Setting the DTC 

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

Action Taken When the DTC Sets 

z

The I/P module disable switch is defaulted to a calibrated state.  

z

The SDM commands ON the AIR BAG indicator via Class 2 serial data.  

z

The SDM toggles the I/P module disable switch AIR BAG indicator ON and OFF every 5 seconds.  

Conditions for Clearing the DTC 

z

The condition responsible for setting the DTC no longer exists.  

z

You issue a scan tool CLEAR DTCs command.  

z

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 I/P module disable switch signal and the I/P module suppression indicator control 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. 

3: Observes the state of the I/P module disable switch, normal state being ON.  

4: Tests for a malfunctioning I/P module disable switch.  

5: Tests for a malfunctioning SDM.  

 

2004 Hummer H2 

2004 RESTRAINTS SIR - Hummer H2

  

6: Tests for a short in the I/P module disable switch signal circuit.  

7: Tests for a short in the I/P module suppression indicator control circuit.  

DTC B0091 

Step

Action

Yes

No

Schematic Reference:SIR Schematics 
Connector End View Reference:SIR Connector End Views

1

Did you perform the Diagnostic System Check - SIR?

Go to Step 2

Go to Diagnostic 

System Check - 

SIR

2

1. Turn OFF the ignition.  

2. Disconnect the I/P module disable switch. Refer to 

Inflatable Restraint Instrument Panel (I/P) Module 
Disable Switch Replacement .  

3. Inspect the I/P module disable switch connector for 

corrosion or damage. 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 

11

Go to Step 3

3

1. Reconnect the I/P module disable switch connector.  

2. Turn the I/P module 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 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 I/P module 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 I/P module disable switch. Refer to 

Inflatable Restraint Instrument Panel (I/P) 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.  

 

2004 Hummer H2 

2004 RESTRAINTS SIR - Hummer H2

  

DTC B0100, B0101, B0102, B0103, B0104, OR B0105 

Circuit Description 

The inflatable restraint electronic frontal sensor (EFS) utilizes a unidirectional 2-wire circuit. The EFS 
modulates current on the interface to send ID, State of Health, and deployment commands to the inflatable 
restraint sensing and diagnostic module (SDM). The SDM serves as a power source and a ground for the EFS. 
When the ignition is turned on and input power from the SDM is first detected, the EFS responds by performing 
internal diagnostics and sending an ID to the SDM. The SDM considers the ID to be valid if the response time 
is less than 5 seconds. The EFS continually communicates status messages to the SDM, which determines if a 

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 I/P module disable switch signal circuit for a short. Refer 
to Circuit Testing and Wiring Repairs in Wiring Systems. 
Did you find and correct the condition?

Go to Step 

11

Go to Step 7

7

Test the I/P module suppression indicator control circuit for a 
short. Refer to Circuit Testing and Wiring Repairs in Wiring 
Systems. 
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 in Wiring Systems.  

Did you find and correct the condition?

Go to Step 

11

Go to Step 9

9

Replace the SDM. Refer to Inflatable Restraint Sensing and 
Diagnostic Module Replacement . 
Did you complete the replacement?

Go to Step 

11

-

10

Replace the I/P module disable switch. Refer to Inflatable 
Restraint Instrument Panel (I/P) 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 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

 

2004 Hummer H2 

2004 RESTRAINTS SIR - Hummer H2

  

fault is present in the EFS circuit. When a fault is detected, the SDM may reset the EFS up to two times by 
removing and reapplying power to it. If the fault is still present, the SDM will set a diagnostic trouble code 
(DTC). 

Conditions for Running the DTC 

Ignition 1 Voltage is within the normal operating voltage range of 9-16 volts. 

Conditions for Setting the DTC 

z

DTC B0100 for the EFS-LF or B0103 for the EFS-RF will set when one of the following conditions 
occur: 

{

A valid ID message is not received within 5 seconds of the EFS being powered up.  

{

A status message is not received.  

{

The SDM has reset the EFS twice without detecting a valid ID message.  

z

DTC B0101 for the EFS-LF or B0104 for the EFS-RF will set when the SDM has received a NOK 
message from the EFS.  

z

DTC B0102 for the EFS-LF or B0105 for the EFS-RF will set when one of the following conditions 
occur: 

{

The SDM has received an ID message from the EFS which does not match the ID stored in the 
SDM memory.  

{

The SDM has reset the EFS twice without detecting the correct ID message.  

Action Taken When the DTC Sets 

The SDM commands ON the AIR BAG warning lamp via Class 2 serial data. 

Conditions for Clearing the DTC 

z

The DTC will clear when the condition responsible for setting the DTC no longer exists and the scan tool 
Clear DTCs function is used.  

z

A history DTC will clear once 255 malfunction free ignition cycles have occurred.  

Diagnostic Aids 

The following are conditions that may cause the malfunction: 

z

A short to ground or voltage in the EFS circuit  

z

High or low resistance in the EFS circuit  

z

Improper EFS installed on vehicle  

Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and connectors may 
result in misdiagnosis, causing a part replacement with the reappearance of the malfunction. If an intermittent 
malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

 

2004 Hummer H2 

2004 RESTRAINTS SIR - Hummer H2