Hummer H2. Manual - part 768

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.

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

The following conditions may cause an intermittent malfunction:

{

A poor connection

{

Rubbed-through wire insulation

{

A broken wire inside the insulation

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 Inoperative

Step

Action

Yes

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

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

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

2004 Hummer H2

2004 BRAKES Anti-Lock Brake System - Hummer H2

REPAIR INSTRUCTIONS

ABS AUTOMATED BLEED PROCEDURE

1. Install a scan tool to the vehicle.

2. Start the engine and allow the engine to idle.

3. Using the scan tool, begin the automated bleed procedure.

4. Follow the instructions on the scan tool to complete the automated bleed procedure. Apply the brake

pedal when instructed by the scan tool.

5. Turn the ignition OFF.

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

Go to Diagnostic

System Check -

ABS

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

NOTE:

When adding fluid to the brake master cylinder reservoir, use only Delco
Supreme 11(R), GM P/N 12377967 (Canadian P/N 992667), or equivalent DOT-3
brake fluid from a clean, sealed brake fluid container. The use of any type of
fluid other than the recommended type of brake fluid, may cause contamination
which could result in damage to the internal rubber seals and/or rubber linings
of hydraulic brake system components.

NOTE:

Refer to Brake Fluid Effects on Paint and Electrical Components Notice in
Cautions and Notices.

IMPORTANT: The base hydraulic brake system must be bled before performing this

automated bleeding procedure. If you have not yet performed the base
hydraulic brake system bleeding procedure, refer to Hydraulic Brake System
Bleeding (Manual) or Hydraulic Brake System Bleeding (Pressure) in Hydraulic
Brakes before proceeding.

2004 Hummer H2

2004 BRAKES Anti-Lock Brake System - Hummer H2

6. Remove the scan tool from the vehicle.

7. Fill the brake master cylinder reservoir to the maximum-fill level with Delco Supreme 11(R), GM P/N

12377967 (Canadian P/N 992667), or equivalent DOT-3 brake fluid from a clean, sealed brake fluid
container.

8. Bleed the hydraulic brake system. Refer to Hydraulic Brake System Bleeding (Manual) or Hydraulic

Brake System Bleeding (Pressure) in Hydraulic Brakes.

9. With the ignition OFF, apply the brakes 3-5 times, or until the brake pedal becomes firm, in order to

deplete the brake booster power reserve.

10. Slowly depress and release the brake pedal. Observe the feel of the brake pedal.

11. If the brake pedal feels spongy, repeat the automated bleeding procedure. If the brake pedal still feels

spongy after repeating the automated bleeding procedure inspect the brake system for external leaks.
Refer to Brake System External Leak Inspection in Hydraulic Brakes.

12. Turn the ignition key ON, with the engine OFF; check to see if the brake system warning lamp remains

illuminated.

13. If the brake system warning lamp remains illuminated, DO NOT allow the vehicle to be driven until it is

diagnosed and repaired. Refer to Symptoms - Hydraulic Brakes in Hydraulic Brakes.

14. Drive the vehicle to exceed 13 km/h (8 mph) to allow ABS initialization to occur. Observe brake pedal

feel.

15. If the brake pedal feels spongy, repeat the automated bleeding procedure until a firm brake pedal is

obtained.

ELECTRONIC BRAKE CONTROL MODULE REPLACEMENT

Removal Procedure

1. Turn the ignition switch to the OFF position.

2. Raise the Vehicle. Refer to Lifting and Jacking the Vehicle in General Information.

3. Disconnect the EBCM harness connector.

4. Remove any dirt/debris from the assembly.

NOTE:

To prevent equipment damage, never connect or disconnect the wiring
harness connection from the EBCM with the ignition switch in the ON
position.

2004 Hummer H2

2004 BRAKES Anti-Lock Brake System - Hummer H2

Fig. 5: EBCM & BPMV
Courtesy of GENERAL MOTORS CORP.

5. Remove the 6 retainers (2) that connect the EBCM to the BPMV.

6. Separate the EBCM (1) from the BPMV (4) by gently pulling apart until separated.

7. Disconnect the pump motor connector (3) at the bottom of the EBCM.

Installation Procedure

IMPORTANT: Do not pry apart using a tool. Be careful not to damage the BPMV surface.

IMPORTANT: Do NOT damage the solenoid valves when you remove the EBCM from the

BPMV.

2004 Hummer H2

2004 BRAKES Anti-Lock Brake System - Hummer H2

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