Hummer H2. Manual - part 189

1. Programming the BCM  

2. Programming Theft Deterrent System Components  

Programming the BCM 

Perform the BCM special function "Request BCM Info. for SPS", then connect the scan tool to SPS terminal. 
Refer to Service Programming System (SPS) in Programming. 

Programming Theft Deterrent System Components 

Perform the Programming Theft Deterrent System Components in Theft Deterrent after successfully 
finishing the Setup New BCM procedure. If the Programming Theft Deterrent System Components in the 
Theft Deterrent procedure is not performed after a BCM replacement, one of the following conditions will 
occur: 

z

The vehicle will not be protected against theft by the PASSLOCK system.  

z

The engine will not crank nor start.  

1. Turn the ignition OFF for 10 seconds.  

2. Connect the scan tool to the data link connector.  

3. Turn the ignition ON with the engine OFF.  

4. Use the scan tool in order to retrieve history DTCs from all modules.  

5. Clear all history DTCs.  

DESCRIPTION AND OPERATION 

BODY CONTROL SYSTEM DESCRIPTION AND OPERATION 

BCM Functions 

The body control module (BCM) performs multiple body control functions. The BCM can control devices 
directly connected to its outputs based on input information. The BCM evaluates this information and controls 
certain body control systems by commanding outputs on or off. The BCM control inputs can be: 

z

Sensors and switches that are directly connected to the BCM  

z

Class 2 serial data received from other control modules connected to the class 2 serial data link. 

IMPORTANT: The following procedures must be followed:

IMPORTANT: After the procedure is completed, the personalization settings of the BCM are 

set to a default setting. Inform the customer that the personalization must be 
set again.

IMPORTANT: After programming, perform the following to avoid future misdiagnosis:

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Body Control System - Hummer H2

  

The BCM is also capable of controlling other vehicle systems that are not directly wired to the BCM. The BCM 
does this by sending specific messages on the class 2 serial data link. The control module capable of performing 
the required function will respond to the BCM message. 

The BCM controls these functions: 

z

Audible warnings - Refer to Audible Warnings Description and Operation in Instrument Panel, 
Gauges and Console  

z

Automatic door locks - Refer to Power Door Locks Description and Operation in Doors  

z

Automatic headlamp control - Refer to Exterior Lighting Systems Description and Operation in 
Lighting Systems  

z

Interior lighting - Refer to Interior Lighting Systems Description and Operation in Lighting Systems  

z

Keyless entry (AUO option) - Refer to Keyless Entry System Description and Operation in Keyless 
Entry.  

z

Passlock theft deterrent - Refer to Vehicle Theft Deterrent (VTD) Description and Operation in Theft 
Deterrent.  

z

Retained accessory power (RAP) - Refer to Retained Accessory Power (RAP) Description and 
Operation in Retained Accessory Power  

Serial Data Power Mode 

On vehicles that have several control modules connected by serial data circuits, one module is the power mode 
master (PMM). On this vehicle the PMM is the body control module (BCM). The BCM uses 3 signals from the 
ignition switch. These are the Ignition 0, Ignition 1, and Accessory. 

To determine the correct power mode the BCM uses: 

z

The state of these signals  

z

The sequence of switch closures received by the BCM  

z

The status of the engine run flag  

The chart indicates the power modes detected and transmitted by the BCM: 

Correct Ignition Switch Inputs 

Fail-safe Operation 

Ignition Key Position Power Mode Parameter Engine Running

Sampled Ignition Signal State

Accessory Ignition 1 Ignition 0

OFF

Off-Awake or RAP

No

Inactive

Off

Off

UNLOCK

Unlock or RAP Unlock

No

Inactive

Off

On

ACC

Accessory

No

Active

Off

On

ON

Run

No

Active

On

On

START

Crank

No

Inactive

On

On

ON

Run

Yes

Active

On

On

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Body Control System - Hummer H2

  

Since the operation of the vehicle systems depends on the power mode, there is a fail-safe plan in place should 
the BCM fail to send a power mode message. The fail-safe plan covers modules with discrete ignition signal 
inputs as well as those modules using exclusively serial data control of power mode. 

Serial Data Messages 

The modules that depend exclusively on serial data messages for power modes stay in the state dictated by the 
last valid BCM message until they receive the engine status from the PCM. If the BCM fails, the modules 
monitor the serial data circuit for the engine run flag serial data. If the engine run flag serial data is true, 
indicating that the engine is running, the modules fail-safe to Run. In this state the modules and their 
subsystems can support all operator requirements. If the engine run flag serial data is false, indicating that the 
engine is not running, the modules fail-safe to OFF-AWAKE. In this state the modules are constantly checking 
for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs 
from other modules on the vehicle. 

Discrete Ignition Signals 

Those modules that have discrete ignition signal inputs also remain in the state dictated by the last valid BCM 
message received on the serial data circuits. They then check the state of their discrete ignition input to 
determine the current valid state. If the discrete ignition input is active, B+, the modules will fail-safe to the 
RUN power mode. If the discrete ignition input is not active, open or 0 voltage, the modules will fail-safe to 
OFF-AWAKE. In this state the modules are constantly checking for a change status message on the serial data 
circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Body Control System - Hummer H2

  

2004 ACCESSORIES & EQUIPMENT

Garage Door Opener - Hummer H2 

SPECIFICATIONS 

FASTENER TIGHTENING SPECIFICATIONS 

Fastener Tightening Specifications 

SCHEMATIC AND ROUTING DIAGRAMS 

GARAGE DOOR OPENER SCHEMATICS 

Fig. 1: Garage Door Opener 
Courtesy of GENERAL MOTORS CORP. 

COMPONENT LOCATOR 

Application

Specification

Metric

English

Transmitter Module Retaining Screws

2 N.m

18 lb in

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Garage Door Opener - Hummer H2

  

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Garage Door Opener - Hummer H2