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Hummer H2. Manual - part 169

The scan tool displays the state of the ignition switch. The scan tool displays ACTIVE when the ignition
switch is in the RUN or CRANK position.

Ignition 3

The scan tool displays the state of the ignition switch. The scan tool displays ACTIVE when the ignition
switch is in the RUN position.

Module Part Number

The scan tool displays the part number assigned to the BCM that is currently in the vehicle.

Passlock(tm) Code

The scan tool displays the validity of the Passlock(tm) code received by the BCM. The scan tool displays
OPEN, SHORTED, TAMPER and a valid code as a numeric value (1-10).

Passlock(tm) Data Voltage

The scan tool displays the voltage code from the Passlock(tm) sensor to the body control module (BCM).
A valid Passlock(tm) sensor voltage of 5 volts will be displayed on the scan tool when the ignition
cylinder is turned to the on position. Once the ignition cylinder has been rotated to the crank position the
Passlock(tm) voltage will drop from 5 to 0.86-4.28 volts depending on which of the 10 possible Passlock
(tm) sensors the vehicle is equipped with. The BCM then determines if the voltage received is a valid or
invalid code. The scan tool will continue to display the Passlock(tm) voltage code (0.86-4.28 volts)
received by the BCM when the ignition cylinder returns to the on/run position.

Passlock(tm) Ignition Cycles

The scan tool displays the amount of times the ignition switch has been cycled.

Passlock(tm) Power

The scan tool displays the state of the Passlock(tm) 12-volt power supply from the BCM.

Passlock(tm) State

The scan tool displays the state of the Passlock(tm) system.

Seed and Key Timer

The scan tool displays 0-2550 seconds. The scan tool displays the current state of the Seed and Key
Timer, which must time out in order for the relearn procedure to be complete.

PCM/VCM in VTD Fail Enable

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Theft Deterrent - Hummer H2

The scan tool displays which state the Powertrain Control Module (PCM) is currently in for the Vehicle
Theft Deterrent (VTD).

Security Calibration Number

The scan tool displays the security calibration part number in the BCM.

Security Lamp State

The scan tool displays the state of the SECURITY lamp. The scan tool displays ON, OFF or FLASHING.

Security Suffix

The scan tool displays the security identification number in the BCM.

Tamper Timer

The scan tool displays the time remaining when in the tamper mode. The timer starts when the ignition
switch is turned to the RUN position and the BCM receives a Passlock(tm) data voltage different from the
last learned voltage. The timer has a delay of 10 minutes and will stay active even if the ignition switch is
cycled from the RUN to the OFF position.

VCM/PCM Fail Enable

The scan tool displays the state of the VCM/PCM fail enable mode. The scan tool displays YES when the
Passlock(tm) system transitions from the Monitor Passlock(tm) Data state to the VCM/PCM Fail Enable
state.

VTD Auto Learn Timer

The scan tool displays which state the learn timer for the VTD is currently in.

VTD Fuel Disable

The scan tool displays the state of which the fuel delivery system is in.

VTD Fuel Disable Until Ign. OFF

The scan tool display the state of which the fuel delivery system is in according to the ignition switch
position.

DIAGNOSTIC TROUBLE CODE (DTC) LIST

Diagnostic Trouble Code (DTC) List

DTC

Diagnostic Procedure

Module

IMPORTANT:

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Theft Deterrent - Hummer H2

DTC B2947

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

The BCM detects a short to ground on the Passlock sensor power circuit for one second, with the ignition
switch in the ACCESSORY, ON, or START position.

Action Taken When the DTC Sets

The BCM stores DTC B2947 in memory.

The BCM sends a message to the instrument cluster to turn the SECURITY indicator ON.

In addition, the BCM will take one of two actions:

{

If the Passlock sensor power circuit is shorted to ground when attempting to start the engine, the

Before you use this table, diagnose P0601, P0602, P0604, and P0606. Refer to Diagnostic System
Check - Theft Deterrent .

B2947

DTC B2947

BCM

B2948

DTC B2948

BCM

B2957

DTC B2957

BCM

B2958

DTC B2958

BCM

B2960

DTC B2960

BCM

B2973

Content Theft Deterrent (CTD) Does Not Disarm with Key Lock

BCM

B3031

DTC B3031

BCM

B3033

DTC B3033

BCM

P1626

DTC P1626

PCM

P1631

DTC P1631

PCM

PXXXX Other PCM DTCs
Refer to Diagnostic System Check - Engine Controls in Engine Controls - 6.0L (LQ4).

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Theft Deterrent - Hummer H2

BCM will NOT send a message to the PCM to enable fuel delivery to the engine. The vehicle will
exhibit an engine no start or starts then stalls condition.

{

If the Passlock sensor power circuit is shorted to ground after the engine has started, the BCM
enters a fail-enable mode. Upon subsequent engine start attempts, the BCM will send a password
message to the PCM via the class 2 serial data link to enable fuel delivery to the engine. The engine
will start.

Conditions for Clearing the DTC

The BCM no longer detects a short to ground in the Passlock sensor power circuit.

When a short to ground is no longer present on the Passlock sensor power circuit, the ignition switch
must be cycled from OFF to ON before this DTC can change from a current DTC to a history DTC.

A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no
longer present.

Diagnostic Aids

Inspect for a short between the Passlock sensor power circuit and the Passlock sensor ground circuit, or a short
to ground on the Passlock sensor power circuit.

Test Description

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

2: Verifies that DTC B2947 is a current DTC.

3: Tests for a short to ground in the Passlock(tm) sensor or the pigtail harness.

DTC B2947

Step

Action

Yes

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

Did you perform the Theft Deterrent Diagnostic System
Check?

Go to

Step 2

Go to Diagnostic System
Check - Theft Deterrent

1. Install a scan tool.

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

3. Select the body control module display DTCs

function on the scan tool.

Does the scan tool display DTC B2947 as a current DTC?

Go to

Step 3

Go to Testing for

Intermittent Conditions and

Poor Connections in Wiring

Systems

1. Disconnect the Passlock(tm) sensor connector.

2. Measure the voltage between the Passlock(tm)

battery voltage circuit and a good ground.

Does the voltage measure approximately battery voltage?

Go to

Step 6

Go to Step 4

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Theft Deterrent - Hummer H2

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