Hummer H2. Manual — part 171

z

The DTC will clear once the ignition cycle has occurred without the fault recurring.

z

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

z

Using a scan tool.

Diagnostic Aids

z

Use a scan tool in order to inspect the Passlock(tm) data voltage and the Passlock(tm) code.

z

Inspect the Passlock(tm) sensor harness for an intermittent or a short to ground. Refer to Testing for
Intermittent Conditions and Poor Connections in Wiring Systems.

z

Following a repair the tamper timer needs 10 minutes in order to expire.

Test Description

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

3: Tests for proper operation of the circuit in the high voltage range.

4: Tests for a short to ground in the Passlock(tm) sensor signal circuit.

DTC B2957

Step

Action

Value

(s)

Yes

No

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

1

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

-

Go to Step 2

Go to Diagnostic

System Check -

Theft Deterrent

2

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. With a scan tool, observe the Passlock

data voltage in the Body Control
Module Security Data list.

Does the scan tool indicate that the Passlock
(tm) data voltage is within the specified
range?

0.4-

4.9 V

Go to Testing for

Intermittent Conditions

and Poor Connections

in Wiring Systems

Go to Step 3

1. Turn OFF the ignition.

2. Disconnect the Passlock (tm) sensor

connector.

3. Turn ON the ignition, with the engine

OFF.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Theft Deterrent - Hummer H2

3

4. With a scan tool, observe the Passlock

(tm) data voltage in the Body Control
Module Security Data list.

Does the scan tool indicate that the Passlock
(tm) data voltage is greater than the specified
value?

4.9 V

Go to Step 7

Go to Step 4

4

Test the Passlock(tm) sensor signal circuit for
a short to ground. Refer to Circuit Testing
and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

-

Go to Step 10

Go to Step 5

5

Inspect for poor connections at the BCM.
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 10

Go to Step 6

6

Replace the body control module. Refer to
Body Control Module Replacement in Body
Control System.Did you complete the
replacement?

IMPORTANT:

When replacing the BCM, refer to Body
Control Module (BCM) Programming/RPO
Configuration in Body Control System.

-

Go to Step 10

-

7

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 10

Go to Step 8

8

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 9

-

9

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

-

Go to Step 10

-

10

1. Use the scan tool in order to clear the

DTCs.

2. Turn OFF the ignition.

3. Turn ON the ignition, with the engine

OFF.

4. Select the body control module display

-

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Theft Deterrent - Hummer H2

DTC B2958

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

z

The ignition switch is ON.

z

The BCM signal input is greater than 4.9 volts for 1 second after turning the ignition switch to the
CRANK position.

Action Taken When the DTC Sets

z

The DTC will set only when the engine is running

z

The BCM will be in the fail enable mode allowing the vehicle to start and run.

z

The security indicator will be ON.

Conditions for Clearing the DTC

z

The current DTC will clear once an ignition cycle has occurred without the fault recurring.

z

After 100 concurrent ignition cycles occur without the fault recurring, a history DTC clears.

z

Using a scan tool.

Diagnostic Aids

z

Use a scan tool in order to inspect the Passlock(tm) data voltage and the Passlock(tm) code.

z

Inspect the Passlock(tm) sensor harness for an intermittent or a short to battery. Refer to Testing for
Intermittent Conditions and Poor Connections in Wiring Systems.

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

z

You may be directed to this table from the VTD Diagnostic System Check without a DTC B2958 being
set. If you were directed to this table, follow all of the steps in this diagnostic table.

z

When directed to this table, DTC B2958 may have a history status.

Test Description

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

3: Tests for proper operation of the circuit in the high voltage range.

4: Tests for proper operation of the circuit in the low voltage range.

5: Tests for high resistance or an open in the 12V reference circuit.

7: Tests for a short to voltage, a high resistance, or an open in the signal circuit.

8: Tests for high resistance or an open in the ground circuit.

DTC B2958

Step

Action

Value

(s)

Yes

No

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

1

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

-

Go to Step 2

Go to Diagnostic

System Check -

Theft Deterrent

2

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. With a scan tool, observe the Passlock

(tm) Data Voltage in the Body Control
Module Security Data list.

Does the scan tool indicate that the Passlock
Data Voltage is within the specified range?

0.4-

4.9 V

Go to Testing for

Intermittent Conditions

and Poor Connections

in Wiring Systems

Go to Step 3

3

1. Turn OFF the ignition.

2. Disconnect the Passlock(tm) sensor.

3. Turn ON the ignition, with the engine

OFF.

4. With a scan tool observe the Passlock

(tm) Data Voltage in the Body Control
Module Security Data list.

Does the scan tool indicate that the Passlock
(tm) Data Voltage is greater than the specified

4.9 V

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Theft Deterrent - Hummer H2