Hummer H2. Manual — part 240

pulse width modulation to carry data and depending on the message it may operate faster or slower. The bus
will float at a nominal 7.0 volts during normal operation. Each module can pull this lower during the
transmission. The bus is not at battery positive voltage or ground potential during normal operation. When the
ignition switch is in RUN, each module communicating on the class 2 serial data line sends a state of health
(SOH) message every 2 seconds to ensure that the module is operating properly. When a module stops
communicating on the class 2 serial data line, for example if the module loses power or ground, the SOH
message it normally sends on the data line every 2 seconds disappears. Other modules on the class 2 serial data
line, which expect to receive that SOH message, detect its absence; those modules in turn set an internal DTC
associated with the loss of SOH of the non-communicating module. The DTC is unique to the module which is
not communicating, for example, when the inflatable restraint sensing and diagnostic module (SDM) SOH
message disappears, several modules set DTC U1088. Note that a loss of serial data DTC does not normally
represent a failure of the module that set it.

On some vehicles, if the PCM is unable to communicate with the VTD system after the vehicle has started, the
PCM will consider the VTD system to be malfunctioning. The PCM will enter a fail enable state and will
command the security indicator to illuminate. When the PCM is in a fail enable state the vehicle will NOT stall
or stop running. If the PCM is in a fail enable state when the ignition is switched OFF, the PCM will remain fail
enable until communications with the VTD system has been restored. When the PCM is in a fail enable state the
VTD system is NOT active and the vehicle will start. This feature is NOT available on all GM vehicle lines.

Data Link Connector (DLC)

The data link connector (DLC) is a standardized 16 cavity connector. Connector design and location is dictated
by an industry wide standard, and is required to provide the following:

z

Scan tool power battery positive voltage at terminal 16.

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Scan tool power ground at terminal 4.

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Common signal ground at terminal 5.

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Class 2 signal at terminal 2.

Class 2 Serial Data Line

The class 2 serial data communications circuit on this vehicle is in a star configuration. This configuration has 3
splice packs, located as follows:

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The splice pack - SP205 located near the data link connector

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The splice pack - SP206 located under the steering column

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The splice pack - SP207 located under the LH cowl panel

There is also a direct redundant class 2 serial data circuit between BCM and PCM.

The following modules communicate on the class 2 serial data circuit:

z

Splice pack - SP205 attaches to:

{

BCM

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Data Link Communications - Hummer H2

{

DDM

{

EBCM

{

ESC

{

FPDM

{

HVAC control module

{

IPC

{

PCM

{

Radio

{

TCSCM

z

Splice pack - SP206 attaches to:

{

Audio amplifier (early production), refer to Radio/Audio System Description and Operation in
Entertainment for more information.

{

RSA control

{

VCIM

z

Splice pack - SP207 attaches to DSM and SDM.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Data Link Communications - Hummer H2

2004 ACCESSORIES & EQUIPMENT

Programming - Hummer H2

REPAIR INSTRUCTIONS

SERVICE PROGRAMMING SYSTEM (SPS)

For step by step programming instructions, please refer to the techline information system (TIS) terminal.

Review the information below to ensure proper programming protocol.

Ensure the following conditions are met before programming a control module:

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Vehicle system voltage

{

There is not a charging system concern. All charging system concerns must be repaired before
programming a control module.

{

Battery voltage is greater than 12 volts but less than 16 volts. The battery must be charged before
programming the control module if the battery voltage is low.

{

A battery charger is NOT connected to the vehicle's battery. Incorrect system voltage or voltage
fluctuations from a battery charger, may cause programming failure or control module damage.

{

Turn OFF or disable any system that may put a load on the vehicle's battery, such as the following
components:

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Twilight sentinel

z

Interior lights

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Daytime running lights (DRL) - Applying the parking brake, on most vehicles, disables the
DRL system. Refer to the Owner's manual.

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Heating, ventilation, and air conditioning (HVAC) systems

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Engine cooling fans, radio, etc.

z

The ignition switch must be in the proper position. The Tech 2 prompts you to turn ON the ignition, with
the engine OFF. DO NOT change the position of the ignition switch during the programming procedure,
unless instructed to do so.

z

Make certain all tool connections are secure, including the following components and circuits:

IMPORTANT: DO NOT program a control module unless you are directed by a service

procedure or you are directed by a General Motors Corporation service
bulletin. Programming a control module at any other time will not permanently
correct a customer's concern.
It is essential that the Tech 2 and the TIS terminal are both equipped with the
latest software before performing service programming system (SPS).
Some modules will require additional programming/setup events performed
before or after programming.
Review the appropriate service information for these procedures.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Programming - Hummer H2

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Programming - Hummer H2

{

The control module Serial Data Link Tester

{

The RS-232 communication cable port

{

The connection at the data link connector (DLC)

{

The voltage supply circuits

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DO NOT disturb the tool harnesses while programming. If an interruption occurs during the
programming procedure, programming failure or control module damage may occur.

z

DO NOT turn OFF the ignition if the programming procedure is interrupted or unsuccessful. Ensure that
all control module and DLC connections are secure and the TIS terminal operating software is up to date.
Attempt to reprogram the control module. If the control module cannot be programmed, replace the
control module.

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Programming - Hummer H2