Hummer H2. Manual - part 206

2004 ACCESSORIES & EQUIPMENT

Retained Accessory Power - Hummer H2 

SCHEMATIC AND ROUTING DIAGRAMS 

RETAINED ACCESSORY POWER (RAP) SCHEMATICS 

Fig. 1: Retained Accessory Power (RAP) 
Courtesy of GENERAL MOTORS CORP. 

DIAGNOSTIC INFORMATION AND PROCEDURES 

DIAGNOSTIC STARTING POINT - RETAINED ACCESSORY POWER 

Begin the system diagnosis with the Diagnostic System Check - Retained Accessory Power . The diagnostic 
system check will provide the following information: 

z

The identification of the control modules which command the system  

z

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

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Retained Accessory Power - Hummer H2

  

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Retained Accessory Power - Hummer H2

  

z

The identification of any stored diagnostic trouble codes 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 - RETAINED ACCESSORY POWER 

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: This step tests for valid system power moding in all ignition switch positions.  

5: 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.  

Diagnostic System Check - Retained Accessory Power 

Step

Action

Yes

No

Schematic Reference:Data Link Connector (DLC) Schematics in Data Link Communications

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 body control module.  

Does the scan tool communicate with the 
body control module?

Go to Step 3

Go to Scan Tool Does Not 

Communicate with Class 2 

Device in Data Link 

Communications

3

1. Access the class 2 power mode 

IMPORTANT:

Open the driver door and leave it open 
during this test. This will disable the RAP 
power mode and eliminate this power 
mode from the power mode parameter 
list.

IMPORTANT:

The engine may start during the 
following step. Turn OFF the engine as 
soon as you have observed the Crank 
power mode.

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Retained Accessory Power - Hummer H2

  

SCAN TOOL DATA LIST 

BCM Scan Tool Data List 

DDM Scan Tool Data List 

parameter in the diagnostic circuit 
check menu on the scan tool.  

2. Rotate the ignition switch through all 

positions while observing the class 2 
power mode parameter.  

Does the class 2 power mode parameter 
reading match the ignition switch position 
for all switch positions?

Go to Step 4

Go to Power Mode 

Mismatch in Body Control 

System

4

Select the body control module display 
DTCs function on the scan tool. 
Does the scan tool display any DTCs?

Go to Step 5

Go to Step 7

5

Does the scan tool display any DTCs which 
begin with a "U"?

Go to Diagnostic 

Trouble Code (DTC) 

List in Data Link 

Communications

Go to Step 6

6

Does the scan tool display DTC B1000 or 
B1440?

Go to Diagnostic 

Trouble Code (DTC) 

List in Body Control 

System

Go to Step 7

7

Test the Courtesy Lamps for proper 
operation after closing and opening each 
door. Refer to Interior Lighting Systems 
Description and Operation in Lighting 
Systems. 
Do the Courtesy Lamps operate properly?

Go to Symptoms - 

Retained Accessory 

Power

Go to Symptoms - 

Lighting Systems in 

Lighting Systems

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Operating Conditions: Ignition ON, Engine OFF

Ignition 0

Inputs

On/Off

On

Ignition 1

Inputs

On/Off

On

Ignition Accessory

Inputs

Active/Inactive

Active

Left Rear/Rear Cargo Door Ajar Switch

Inputs

On/Off

Off

RAP Relay

Outputs

On/Off

On

Right Rear Door Ajar Sw.

Inputs

On/Off

Off

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Operating Conditions: Ignition ON, Engine OFF

Door Ajar Switch

Inputs

On/Off

Off

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Retained Accessory Power - Hummer H2

  

FPDM Scan Tool Data List 

SCAN TOOL DATA DEFINITIONS 

Door Ajar Switch  

Input from the respective door indicating door status. 

Ignition 0  

Input to the control module from the ignition switch indicating the Ignition 0 position. Switch closed in 
ignition switch positions UNLOCK, ACC, ON, and START. 

Ignition 1  

Input to the control module from the ignition switch indicating the Ignition 1 position. Switch closed in 
ignition switch positions ON and START. 

Ignition Accessory  

Input to the control module from the ignition switch indicating the Ignition Accessory position. Switch 
closed in ignition switch positions ACC and ON. 

Left Rear/Rear Cargo Door Ajar Switch  

Input from the left rear door/rear cargo showing the state of it. 

RAP Relay  

Output indicates the RAP Relay state that the control module has commanded. 

Right Rear Door Ajar Sw.  

Input from the right rear door indicating door status. 

SYMPTOMS - RETAINED ACCESSORY POWER 

Visual/Physical Inspection 

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Operating Conditions: Ignition ON, Engine OFF

Door Ajar Switch

Inputs

On/Off

Off

IMPORTANT: Review the system operation in order to familiarize yourself with the system 

functions. Refer to Retained Accessory Power (RAP) Description and 
Operation .

 

2004 Hummer H2 

2004 ACCESSORIES & EQUIPMENT Retained Accessory Power - Hummer H2