Hummer H2. Manual — part 271

DTC B1025, B1035, B1045, OR B1055

Circuit Description

When the radio is powered up, the radio supplies low level audio signals to the speakers. If the vehicle is
equipped with an audio amplifier, the amplifier will boost the signal sent to the speakers.

Conditions for Running the DTC

The test is performed when the radio switches from OFF to ON. The radio will continue to test for the fault
once every 0.5 seconds.

Conditions for Setting the DTC

The radio sets a current status for this DTC when a short to ground or voltage is detected on any of the speaker
channels for 1.5 seconds.

Action Taken When the DTC Sets

No sound is present from one or more of the speakers.

Conditions for Clearing the DTC

The fault condition is not present for 5 seconds.

Test Description

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

2: This step verifies that the DTC is still present.

3: This step isolates the fault condition.

DTC B1025, B1035, B1045, or B1055

B1025, B1035, B1045, or B1055

DTC B1025, B1035, B1045, or B1055

Radio

B1235

DTC B1235

Radio

B2815

DTC B2815

BCM

Step

Action

Yes

No

Schematic Reference:Radio/Audio System Schematics (non Class 2 Amplifier) or Radio/Audio
System Schematics (Class 2 Amplifier)

1

Did you perform the Diagnostic System Check -
Entertainment System?

Go to

Step 2

Go to Diagnostic System

Check - Entertainment

System

1. Install a scan tool.

2. Turn ON the ignition, with the engine OFF.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Entertainment - Hummer H2

DTC B1235

Circuit Description

The Antenna Enable/Amplifier On Signal is a class 2 signal sent from the radio through the RSA module, when
equipped. The amplifier will reach full output capabilities 900 milliseconds after receiving this signal. The
amplifier will then be capable of class 2 functions 60 milliseconds after being turned ON. This DTC will be set
if the circuit is shorted to ground or battery.

Conditions for Running the DTC

This test is run at least every 50 milliseconds.

Conditions for Setting the DTC

The failure must occur for at least 3 seconds.

Action taken when the DTC Sets

The Antenna Enable/Amplifier On Signal Circuit becomes disabled, causing the controlled module to become
inoperative.

Conditions for Clearing the DTC

2

3. With the scan tool, monitor the DTC Information

for DTC B1025, B1035, B1045 OR B1055.

Does the scan tool indicate that DTC B1025, B1035,
B1045 OR B1055 is current?

Go to

Step 3

Go to Testing for Intermittent

Conditions and Poor

Connections in Wiring Systems

3

Test the speaker outputs from the radio for short to
ground or voltage. Refer to Circuit Testing and Wiring
Repairs in Wiring Systems.
Did you find and correct the condition?

Go to

Step 6

Go to Step 4

4

Inspect for poor connections at the harness connector of
the radio. 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 6

Go to Step 5

5

Replace the radio. Refer to Radio Replacement .Did
you complete the replacement?

IMPORTANT:

Reprogram the radio. Refer to Service Programming
System (SPS) in Programming.

Go to

Step 6

-

6

Operate the system in order to verify the repair.
Did you correct the condition?

System

OK

Go to Step 2

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The failure criteria is no longer detected for 50 milliseconds.

Test Description

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

2: This step helps to determine if the Diversity Antenna System is operating.

3: This step helps to determine if Radio Antenna Module is receiving the proper signal from the radio.

DTC B1235

DTC B1271

Circuit Description

This DTC is generated by the module when the Theft Lock is activated. This occurs when the VIN as received
over the class 2 communication circuit and the VIN as stored in the module memory do not match. This also
occurs when no VIN is received over the class 2 circuit. The only circuit required is the class 2 communications
line.

Conditions for Running the DTC

Step

Action

Yes

No

Schematic Reference:Radio/Audio System Schematics (non Class 2 Amplifier) or Radio/Audio
System Schematics (Class 2 Amplifier)

1

Did you perform the Diagnostic
System Check - Entertainment
System?

Go to Step 2

Go to Diagnostic System

Check - Entertainment

System

2

1. Turn ON the ignition, with

the engine OFF.

2. Turn ON the radio.

3. Press the scan button.

Do the local AM/FM stations come
in clearly?

Go to Testing for

Intermittent Conditions

and Poor Connections in

Wiring Systems

Go to Step 3

3

1. Remove the radio.

2. Test the Antenna

Enable/Amplifier On Signal
Circuit for a short or open.

Did you locate and correct the
condition?

Go to Step 4

Go to Testing for Intermittent

Conditions and Poor

Connections in Wiring

Systems

4

Operate the system in order to
verify the repair.
Did you complete the repair?

System OK

-

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2004 ACCESSORIES & EQUIPMENT Entertainment - Hummer H2

This test is run every 300 milliseconds.

Conditions for Setting the DTC

This DTC is generated by the module when the VIN as received over the class 2 communication circuit and the
VIN as stored in the module memory do not match. This also occurs if no VIN is received over the class 2
circuit. This DTC test runs when the Radio changes from OFF to ON.

Action Taken When the DTC Sets

The Radio does not function. The Radio will display Locked - THEFTLOCK Active.

Conditions for Clearing the MIL/DTC

Re-calibration with the correct calibrations for the vehicle and cycling the Radio to OFF then to ON will clear
the DTC if there is no damage to the Radio.

DTC B1271

DTC B2815

Circuit Description

The steering wheel controls are momentary contact switches that connect a series of resistors so that each
switch selection corresponds to a fixed resistance value. The body control module (BCM) determines which
switch has been pressed by the voltage drop across the corresponding resistance value. The BCM supplies
voltage to the steering wheel controls through the rear wiper/washer switch supply voltage circuit. The BCM
monitors the switch voltage on the remote radio control signal circuit.

Conditions for Running the DTC

Step

Action

Yes

No

1

Did you perform the Diagnostic System Check -
Entertainment System?

Go to

Step 2

Go to Diagnostic System Check -

Entertainment System

2

1. Install a scan tool.

2. Turn ON the ignition, with the engine OFF.

3. With a scan tool clear the radio theft

information.

Does the DTC Reset?

Go to

Step 3

System OK

3

Replace the radio. Refer to Radio
Replacement .Did you complete the replacement?

IMPORTANT:

Perform the radio setup procedure. Refer to
Radio Setup (With RPO UM8)

System

OK

-

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Entertainment - Hummer H2