Hummer H2. Manual — part 767

ABS INDICATOR INOPERATIVE

Circuit Description

The instrument panel cluster (IPC) turns the anti-lock brake system (ABS) indicator ON during the IPC bulb
check for approximately 3 seconds when the ignition switch is turned to the ON position. If the electronic brake
control module (EBCM) sets a diagnostic trouble code (DTC) the EBCM sends the IPC the command to turn
the ABS indicator ON.

Diagnostic Aids

z

It is very important that a thorough inspection of the wiring and connectors be performed. Failure to
carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement
with reappearance of the malfunction.

z

Thoroughly inspect any circuitry that may be causing the complaint for the following conditions:

{

Backed out terminals

{

Improper mating

{

Broken locks

{

Improperly formed or damaged terminals

{

Poor terminal-to-wiring connections

{

Physical damage to the wiring harness

z

The following conditions may cause an intermittent malfunction:

{

A poor connection

{

Rubbed-through wire insulation

{

A broken wire inside the insulation

z

If an intermittent malfunction exists refer to Inducing Intermittent Fault Conditions in Wiring
Systems.

Test Description

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

2: Checks if the scan tool can turn ON and OFF all the indicator lamps in the IPC.

4: Checks if the circuits going to the IPC or the IPC is at fault.

3

Electronic Brake Control Module Replacement .
Is the replacement complete?

Go to

Step 5

-

4

Replace the IPC. Refer to Instrument Panel Cluster (IPC)
Replacement in Instrument Panel, Gauges and Console.
Is the replacement complete?

Go to

Step 5

-

5

Operate the system in order to verify the repair.
Did you correct the condition?

System

OK

Go to Step 2

2004 Hummer H2

2004 BRAKES Anti-Lock Brake System - Hummer H2

ABS Indicator Inoperative

TRACTION OFF INDICATOR ALWAYS ON

Circuit Description

The traction control system (TCS) TRAC OFF indicator is controlled by the instrument panel cluster (IPC) via
class 2 serial data messages from the electronic brake control module (EBCM). When the EBCM sees the TCS
switch fault, the EBCM then disables the TCS and sends a message to the IPC to turn the TRAC OFF indicator
ON. Each time the ignition is cycled from OFF to ON, the TCS is enabled.

Step

Action

Yes

No

Schematic Reference:ABS Schematics
Connector End View Reference:Instrument Panel, Gauges, and Console Connector End Views

1

Did you perform the Diagnostic System Check?

Go to Step 2

Go to Diagnostic

System Check -

ABS

2

1. Using a scan tool, select the Instrument Panel

Cluster (IPC) Special Functions mode.

2. Go to Lamp Test.

3. In the Lamp Test mode you can turn ON or OFF

the instrument panel indicators.

All indicators will turn ON when commanded
ON.

Does the anti-lock brake system (ABS) indicator turn
ON then OFF?

Go to Step 3

Go to Step 4

3

Replace the electronic brake control module (EBCM).
Refer to Electronic Brake Control Module
Replacement .
Is the replacement complete?

Go to Diagnostic

System Check -

ABS

-

4

1. Disconnect the IPC and connect a Test Light

across the appropriate power and ground
terminals.

2. Test Light OFF, repair open in power or ground

circuit to IPC.

3. Test Light ON, check connector for poor

connection to the IPC.

4. If OK, replace the IPC. Refer to Instrument

Panel Cluster (IPC) Replacement in Instrument
Panel, Gauges, and Console.

Is the IPC replacement complete?

Go to Diagnostic

System Check -

ABS

-

2004 Hummer H2

2004 BRAKES Anti-Lock Brake System - Hummer H2

The following conditions will cause the TRAC OFF indicator to illuminate:

z

The EBCM has disabled the TCS due to a DTC.

z

The EBCM has disabled the TCS due to a overheated ABS/TCS hydraulic unit.

z

The IPC bulb check. When the ignition switch is turned to ON, the TRAC OFF indicator will turn ON for
approximately 5 seconds and then turn OFF.

Diagnostic Aids

z

It is very important that a thorough inspection of the wiring and connectors be performed. Failure to
carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement
with reappearance of the malfunction.

z

Thoroughly inspect any circuitry that may be causing the complaint for the following conditions:

{

Backed out terminals

{

Improper mating

{

Broken locks

{

Improperly formed or damaged terminals

{

Poor terminal-to-wiring connections

{

Physical damage to the wiring harness

z

The following conditions may cause an intermittent malfunction:

{

A poor connection

{

Rubbed-through wire insulation

{

A broken wire inside the insulation

z

If an intermittent malfunction exists refer to Inducing Intermittent Fault Conditions in Wiring
Systems.

Test Description

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

2: Checks if the scan tool can turn ON and OFF all the indicator lamps in the IPC.

4: Checks if the circuits going to the IPC or the IPC is at fault.

Traction Off Indicator Always On

Step

Action

Yes

No

Schematic Reference:ABS Schematics
Connector End View Reference:Instrument Panel, Gauges, and Console Connector End Views

1

Did you perform the Diagnostic System Check?

Go to Step 2

Go to Diagnostic

System Check -

ABS

1. Using a scan tool, select the Instrument Panel

2004 Hummer H2

2004 BRAKES Anti-Lock Brake System - Hummer H2

TRACTION OFF INDICATOR INOPERATIVE

Circuit Description

The traction control system (TCS) TRAC OFF indicator is controlled by the instrument panel cluster (IPC) via
class 2 serial data messages from the electronic brake control module (EBCM). When the EBCM sees the TCS
switch fault, the EBCM then disables the TCS, and sends a message to the IPC to turn the TRAC OFF indicator
ON. Each time the ignition is cycled from OFF to ON, the TCS is enabled.

The following conditions will cause the TRAC OFF indicator to illuminate:

z

The EBCM has disabled the TCS due to a DTC.

z

The EBCM has disabled the TCS due to a overheated ABS/TCS hydraulic unit.

z

The IPC bulb check. When the ignition switch is turned to ON, the TRAC OFF indicator will turn ON for
approximately 5 seconds and then turn OFF.

Diagnostic Aids

2

Cluster (IPC) Special Functions mode.

2. Go to Displays Test in Output Control.

3. In the Displays Test mode you can turn ON or

OFF the instrument panel indicators.

All indicators will turn ON when commanded
ON.

Does the TRAC OFF indicator turn ON then OFF?

Go to Step 3

Go to Step 4

3

Replace the electronic brake control module (EBCM).
Refer to Electronic Brake Control Module
Replacement .
Is the replacement complete?

Go to Diagnostic

System Check -

ABS

-

4

1. Disconnect the IPC and connect a Test Light

across the appropriate power and ground
terminals.

2. Test Light OFF, repair open in power or ground

circuit to IPC.

3. Test Light ON, check connector for poor

connection to IPC.

4. If OK, replace the IPC. Refer to Instrument

Panel Cluster (IPC) Replacement in Instrument
Panel, Gauges, and Console.

Is the IPC replacement complete?

Go to Diagnostic

System Check -

ABS

-

2004 Hummer H2

2004 BRAKES Anti-Lock Brake System - Hummer H2