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