Hummer H2. Manual - part 173

DTC B3031

Circuit Description

The Passlock(tm) system is provided in order to prevent vehicle theft if the ignition lock cylinder is forced to
rotate or the ignition switch is operated while separated from the ignition lock cylinder case. The body control
module (BCM) provides security system sensor power and low reference for the Passlock(tm) sensor. The BCM
also measures the security system sensor voltage.

When the correct key is used to start the vehicle, a magnet on the lock cylinder passes close to the Passlock(tm)
sensor within the ignition lock cylinder case. The magnet activates the security hall effect sensor in the Passlock
(tm) sensor which completes a circuit from the security sensor signal circuit through a resistor to the security
sensor low reference circuit. The resistance value will vary from vehicle to vehicle. The BCM will measure the
voltage on the security sensor signal circuit and compare this voltage to a previously learned voltage. If the
voltage measured is within the valid range, the BCM will send a class 2 message to the powertrain control
module (PCM) to enable vehicle starting. If the voltage measured is not within the valid range, a class 2
message will be sent to the PCM to disable starting of the vehicle.

Conditions for Setting the DTC

A new BCM has been installed and the ignition is turned to the ON position but not rotated to the
CRANK position. Once the ignition switch has been rotated to the CRANK position, the BCM will learn
the Passlock(tm) code. The theft relearn procedure will need to be run in order to make the
powertrain/vehicle control module (PCM/VCM) receive the correct fuel enable password.

The BCM is in the learn mode but does not see a valid Passlock(tm) sensor code because of a sensor or a
wiring problem.

Action Taken When the DTC Sets

The vehicle will not run. The security indicator will be ON.

Conditions for Clearing the MIL/DTC

The DTC will clear after an ignition cycle has occurred after the BCM has learned a valid code.

Using a scan tool.

Diagnostic Aids

3. Momentarily rotate the ignition switch to

CRANK.

4. Release the ignition switch to ON.

5. Select the body control module display

DTCs function on the scan tool.

Does the DTC reset?

Go to Step 3

System OK

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Theft Deterrent - Hummer H2

Prior to replacing a BCM, ensure that all of the diagnostics have been completed. Refer to Diagnostic
Trouble Code (DTC) List .

Inspect the Passlock(tm) sensor harness for intermittent or poor connections. Refer to Testing for
Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

The number below refers to the step number on the diagnostic table.

3: Tests for the proper operation of the 12-volt reference Security Sensor Power circuit, sensor ground
circuit, and Passlock(tm) sensor signal (data) circuit. Troubleshoot the appropriate DTC prior to
diagnosing DTC B3031.

DTC B3031

DTC B3033

Step

Action

Yes

Schematic Reference:Theft Deterrent System Schematics

Did you perform the Vehicle Theft Deterrent
(VTD) Diagnostic System Check?

Go to Step 2

Go to Diagnostic System
Check - Theft Deterrent

1. Install a scan tool.

2. Momentarily rotate the ignition switch

to CRANK. Do not start the vehicle.

3. Release the ignition switch to ON.

4. Select the body control module

display DTCs function on the scan
tool.

Does the scan tool display DTC B3031 as a
current DTC?

Go to Step 3

Go to Step 4

Does the scan tool display DTC B2947,
B2948, B2957, B2958, B2960, or B3033?

Go to Diagnostic

Trouble Code (DTC)

List

Go to Step 4

1. Use the scan tool in order to clear the

DTCs.

2. Turn OFF the ignition.

3. Start the vehicle.

4. Select the body control module

display DTCs function on the scan
tool.

Does the DTC reset?

Go to Step 3

System OK

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Theft Deterrent - Hummer H2

Circuit Description

Conditions for Setting the DTC

The BCM will inspect for a tamper code when the ignition switch rotates from ON to CRANK and will
continue to monitor the signal during the engine running period.

The BCM is reading a tamper code from the Passlock(tm) sensor for longer than 1.0 seconds.

Action Taken When the DTC Sets

The vehicle will not run. The security indicator will be flashing.

The Passlock(tm) state is Tamper.

Conditions for Clearing the DTC

The DTC will clear once an ignition cycle occurs without the fault recurring.

The BCM history codes will clear after 100 ignition cycles occur without the fault recurring.

Use a scan tool.

Diagnostic Aids

Prior to replacing a BCM, ensure that all of the diagnostics have been completed. Refer to Diagnostic
Trouble Code (DTC) List .

Inspect the Passlock(tm) sensor harness for intermittent or poor connections. Refer to Testing for
Intermittent Conditions and Poor Connections in Wiring Systems.

The VTD internal diagnostics are not run while the tamper timer is active.

Test Description

The number below refers to the step number on the diagnostic table:

3: Tests for a magnetic field near the ignition lock cylinder.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Theft Deterrent - Hummer H2

DTC B3033

Step

Action

Yes

Schematic Reference:Theft Deterrent System Schematics
Connector End View Reference:Theft Deterrent System Connector End Views

Did you perform the Vehicle Theft Deterrent (VTD)
Diagnostic System Check?

Go to

Step 2

Go to Diagnostic System
Check - Theft Deterrent

1. Install a scan tool.

2. Momentarily rotate the ignition switch to CRANK.

3. Release the ignition switch to ON.

4. Select the body control module display DTCs

function on the scan tool.

Does the scan tool display DTC B3033 as a current DTC?

IMPORTANT:

Do not start the vehicle.

Go to

Step 3

Go to Testing for Intermittent

Conditions and Poor

Connections in Wiring

Systems

Inspect the area around the ignition lock cylinder for any
device which could create a magnetic field audio speaker,
magnet, etc.
Is there a magnetic device near the ignition lock cylinder?

Go to

Step 4

Go to Step 5

Remove the device creating the magnetic force.
Did you complete the repair?

Go to

Step 8

Inspect for poor connections at the Passlock(tm) sensor.
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 8

Go to Step 6

Replace the Passlock(tm) sensor in the electronic column
lock module assembly. Refer to Ignition Lock Cylinder
Case Replacement in Steering Wheel and Column.
Did you complete the replacement?

Go to

Step 7

Perform the Programming Theft Deterrent System
Components procedure.
Is the repair complete?

Go to

Step 8

1. Use the scan tool in order to clear the DTCs.

2. Turn OFF the ignition.

IMPORTANT:

You may have to wait up to 10 minutes in order to reset
the BCM and synchronize all of the Passlock(tm)
components.

IMPORTANT:

Do not start the vehicle.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Theft Deterrent - Hummer H2

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