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