Hummer H2. Manual - part 2028

DTC B0051 

Circuit Description 

The inflatable restraint sensing and diagnostic module (SDM) contains a sensing device (accelerometer) that 
converts vehicle velocity to an electrical signal. The SDM compares this signal to a value stored in memory. 
When the generated signal exceeds the stored value, the SDM performs additional signal processing and 
compares the generated signals to values stored in memory. When two of the generated signals exceed the 
stored values, the SDM will cause current to flow through the inflator modules, deploying the air bags and 
causing DTC B0051 to set. 

This DTC is set when the inflatable restraint sensing and diagnostic module (SDM) has commanded an air bag 
deployment with no faults present. 

Conditions for Running the DTC 

The SDM must be powered up. 

Conditions for Setting the DTC 

Ignition voltage must be present and the inflatable restraint sensing and diagnostic module (SDM) must have 
commanded an air bag deployment. 

Action Taken When the DTC Sets 

z

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

z

The SDM records crash data.  

Conditions for Clearing the DTC 

DTC B0051 is a latched code. You cannot clear a latched code. Replace the SDM after following the 
instructions in the following diagnostic table. 

DTC B0051 

Does the DTC reset?

Go to 

Step 2

System OK

Step

Action

Value

(s)

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

1. Turn OFF the ignition.  

 

2004 Hummer H2 

2004 RESTRAINTS SIR - Hummer H2

  

DTC B0053 

Circuit Description 

The inflatable restraint sensing and diagnostic module (SDM) contains a sensing device (accelerometer) that 
converts vehicle velocity to an electrical signal. The SDM compares this signal to a value stored in memory. 
When the generated signal exceeds the stored value, the SDM performs additional signal processing and 
compares the generated signals to values stored in memory. When two of the generated signals exceed the 
stored values, the SDM will cause current to flow through the inflator modules, deploying the air bags. DTC 
B0053 will set instead of DTC B0051 when a deployment occurs while an inflator circuit fault is present that 
may result in a non-deployment situation in one or more of the inflator modules. 

Conditions for Running the DTC 

The SDM must be powered up. 

Conditions for Setting the DTC 

Ignition voltage must be present and the inflatable restraint sensing and diagnostic module (SDM) must have 
commanded an air bag deployment with loop faults.

2

2. Inspect the vehicle for any signs of air bag 

deployment.  

Does the vehicle exhibit any signs of air bag 
deployment?

-

Go to Step 5

Go to Step 3

3

Inspect the vehicle and undercarriage for any signs 
of impact or collision. 
Does the vehicle exhibit any signs of impact or 
collision?

-

Go to Step 5

Go to Step 4

4

Replace the inflatable restraint sensing and 
diagnostic module (SDM). Refer to Inflatable 
Restraint Sensing and Diagnostic Module 
Replacement . 
Did you complete the replacement?

-

Go to Step 6

-

5

Replace all components and perform inspections as 
required following an accident. Refer to Repairs 
and Inspections Required After a Collision . 
Did you complete the appropriate inspections and 
necessary repairs?

-

Go to Step 6

-

6

1. Reconnect all SIR system components.  

2. Verify that all components, connectors, and 

CPAs are properly mounted.  

Did you complete the repair?

-

Go to Diagnostic 

System Check - 

SIR

-

 

2004 Hummer H2 

2004 RESTRAINTS SIR - Hummer H2

  

Action Taken When the DTC Sets 

z

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

z

The SDM records crash data.  

Conditions for Clearing the DTC 

DTC B0053 is a latched code. You cannot clear a latched code. Replace the SDM after following the 
instructions in the following diagnostic table. 

Diagnostic Aids 

When DTC B0053 is accompanied by additional DTC(s) (other than B0051), repair the malfunction causing the 
other DTC(s) before replacing the SDM. 

DTC B0053 

Step

Action

Value

(s)

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. Inspect the vehicle for any signs of air bag 

deployment.  

Does the vehicle exhibit any signs of air bag 
deployment?

-

Go to Step 5

Go to Step 3

3

Inspect the vehicle and undercarriage for signs of 
impact or collision. 
Does the vehicle exhibit any signs of impact or 
collision?

-

Go to Step 5

Go to Step 4

4

Replace the inflatable restraint sensing and 
diagnostic module (SDM). Refer to Inflatable 
Restraint Sensing and Diagnostic Module 
Replacement . 
Did you complete the replacement?

-

Go to Step 6

-

5

Replace all components and perform inspections as 
required following an accident. Refer to Repairs 
and Inspections Required After a Collision . 
Did you complete the appropriate inspections and 
necessary repairs?

-

Go to Step 6

-

1. Reconnect all SIR system components.  

2. Verify that all components, connectors, and 

 

2004 Hummer H2 

2004 RESTRAINTS SIR - Hummer H2

  

DTC B0090 

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 and I/P module suppression indicator control is low or high 
with the I/P module disable switch indicator OFF for 500 milliseconds. 

Action Taken When the DTC Sets 

z

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

z

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

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 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:

6

CPAs are properly mounted.  

Did you complete the repair?

-

Go to Diagnostic 

System Check - 

SIR

-

 

2004 Hummer H2 

2004 RESTRAINTS SIR - Hummer H2