Hummer H2. Manual — part 2650

Transfer Case Shift Control Module - C3 Terminal Identification

Transfer Case Shift Control Switch - C1 Terminal Identification

B7

-

-

Not Used

B8

GY

596

5-Volt Reference

Connector Part Information

z

12052856

z

4-Way F Metri-Pack 280 Series (BK)

Pin

Wire Color

Circuit No.

Function

A

BK

1550

Ground

B

OG

1640

Battery Positive Voltage

C

RD

1553

Motor Control A

D

BK

1552

Motor Control B

2004 Hummer H2

2004 DRIVELINE/AXLE Transfer Case - BW 4484 - Hummer H2

Transfer Case Shift Control Switch - C2 Terminal Identification

DIAGNOSTIC INFORMATION AND PROCEDURES

DIAGNOSTIC STARTING POINT - TRANSFER CASE

Begin the system diagnosis with the Diagnostic System Check - Transfer Case . The Diagnostic System
Check will provide the following information:

Connector Part Information

z

12064862

z

8-Way F Metri-Pack 150 Series (BK)

Pin

Wire Color

Circuit No.

Function

A

BK

1050

Ground

B

PK

1561

Differential Lock Indicator Control

C

BN

1560

Neutral Indicator Control

D

-

-

Not Used

E

PU/WH

1382

4LO LED Dimming Signal

F

BN/WH

230

Instrument Panel Lamps Dimming Control

G

BN

241

Ignition 3 Voltage

H

L-BU

1693

Switch Signal

Connector Part Information

z

12045813

z

4-Way F Metri-Pack 150 Series (WH)

Pin

Wire Color

Circuit No.

Function

A

GY

596

5-Volt Reference

B

L-GN/BK

1563

4 'HI' Indicator - Control

C

PU/WH

1565

4 'LO' Indicator - Control

D

TN/BK

1566

4 'HI' Indicator - Control

2004 Hummer H2

2004 DRIVELINE/AXLE Transfer Case - BW 4484 - Hummer H2

z

The identification of the control modules that command the system

z

The ability of the control modules to communicate through the serial data circuit

z

The identification of any stored DTCs and their status

The use of the Diagnostic System Check will identify the correct procedure for diagnosing the system and
where the procedure is located.

DIAGNOSTIC SYSTEM CHECK - TRANSFER CASE

These diagnostic procedures will help you to find and repair full time 4WD transfer case (FT4WD) system
malfunctions. This service category also contains information for repairing FT4WD system malfunctions. For
best results, use the diagnostic tables, and follow the sequence listed below:

1. Perform the Transfer Case Diagnostic System Check. All FT4WD diagnostics must begin with the

Transfer Case Diagnostic System Check. The Transfer Case Diagnostic System Check determines the
following:

z

Proper SERVICE 4WD indicator operation.

z

Ability of the transfer case shift control module to communicate through the data link connector
(DLC)

z

Existence of FT4WD DTCs

2. Refer to the diagnostic table as directed by the Transfer Case Diagnostic System Check. The diagnostic

tables will help enable you to diagnose any FT4WD system malfunction. Bypassing these procedures
may result in the following:

z

Extended Diagnostic Time

z

Incorrect Diagnosis

z

Incorrect Parts Replacement

3. Repeat the Transfer Case Diagnostic System Check after you perform any repair or diagnostic

procedures. This will verify that you correctly performed the repair. This will also ensure that other
malfunctions do not exist.

Test Description

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

2: Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a
total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular
condition.

3: A fuse failure will cause no communication this step has you check for this condition.

4: This step determines if the fuse blows when the ignition is turned on.

5: This step determines if there is a short to ground in the battery positive circuit causing the fuse to blow.

6: This step refers to the table for DTC C0306 for further diagnosis if a transfer case mode change is
causing the fuse to blow.

7: The presence of DTCs indicates that the transfer case shift control module has detected a fault. Go to

2004 Hummer H2

2004 DRIVELINE/AXLE Transfer Case - BW 4484 - Hummer H2

symptoms for other concerns.

8: The presence of DTCs which begin with "U" indicate some other module is not communicating. The
specified procedure will compile all the available information before tests are performed.

9: Vehicle speed is provided to the transfer case shift control module via Class 2 and can effect the setting
of DTC C0300. Perform the diagnostics for powertrain DTCs P0502 and P0503 first.

Diagnostic System Check - Transfer Case

Step

Action

Yes

No

1

Install a scan tool.
Does the scan tool power up?

Go to Step 2

Go to Scan Tool Does Not

Power Up in Data Link

Communications

2

1. Turn ON the ignition, with

the engine OFF.

2. Attempt to establish

communication with the
transfer case shift control
module.

Does the scan tool communicate
with the transfer case shift control
module?

Go to Step 7

Go to Step 3

3

1. Turn off the ignition.

2. Check the underhood

TREC fuse.

Did the TREC fuse blow?

Go to Step 4

Go to Scan Tool Does Not

Communicate with Class 2

Device in Data Link

Communications

4

Replace the TREC fuse.
Does the ATC fuse blow
immediately?

Go to Step 5

Go to Step 6

5

Check the battery positive circuit
for a short to ground.
Was the condition found and
corrected?

Go to Step 2

Go to Transfer Case Shift

Control Module Replacement.

6

1. Start the Engine

2. Attempt to shift the transfer

case to different modes.

3. Check the underhood

TREC fuse.

Did the TREC fuse blow?

Go to DTC C0306

Go to Step 2

7

Select the transfer case shift
control module display DTCs
function on the scan tool.

2004 Hummer H2

2004 DRIVELINE/AXLE Transfer Case - BW 4484 - Hummer H2