Hummer H2. Manual — part 1935

1

Point - Heating, Ventilation and Air
Conditioning?

Go to Step 2

Point - Heating, Ventilation

and Air Conditioning in

Heating, Ventilation and Air

Conditioning

2

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

Go to Step 3

Go to Scan Tool Does Not

Power Up in Data Link

Communications

3

1. Turn ON the ignition, with the

engine OFF.

2. Attempt to establish

communication with the
following control modules:

z

HVAC Control Module

z

Body Control Module

z

Powertrain Control
Module

Does the scan tool communicate with
the control modules?

Go to Step 4

Go to Scan Tool Does Not

Communicate with Class 2

Device in Data Link

Communications

4

1. Access the Class 2 Power

Mode in the Diagnostic Circuit
Check on the scan tool.

2. Rotate the ignition switch

through all positions while
observing the Ignition Switch
Power Mode parameter.

Does the Ignition Switch parameter
reading match the ignition switch
position for all switch positions?

IMPORTANT:

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

Go to Step 5

Go to Power Mode Mismatch

in Body Control System

5

Select the display DTCs function on
the scan tool for the following
modules:

z

HVAC Control Module

z

Body Control Module

z

Powertrain Control Module

2004 Hummer H2

2004 HVAC HVAC Systems - Automatic - Hummer H2

SCAN TOOL OUTPUT CONTROLS

HVAC Control Module Scan Tool Output Controls

Does the scan tool display any
DTCs?

Go to Step 6

Go to Symptoms - HVAC

Systems - Automatic

6

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

Go to Scan Tool Does Not

Communicate with Class

2 Device in Data Link

Communications

Go to Step 7

7

Does the scan tool display DTC
B10XX?

Go to Diagnostic Trouble

Code (DTC) List in Body

Control Systems

Go to Step 8

8

Does the scan tool display any DTCs
that are associated with the charging
system?

Go to Diagnostic Trouble

Code (DTC) List in

Engine Electrical

Go to Step 9

9

Does the scan tool display any DTCs
that are associated with the HVAC
system?

Go to Diagnostic Trouble

Code (DTC) List

Go to Diagnostic Trouble

Code (DTC) List in Engine

Controls - 4.8L, 5.3L, and 6.0L

Scan Tool

Output

Control

Additional

Menu Selection

(s)

Description

A/C
Permission

Miscellaneous
Tests

When you select ON, the HVAC control module changes the state of
the A/C Permission parameter to Granted and transmits a clutch
enable message to the PCM over the class 2 serial data circuit. The
A/C compressor clutch engages and remains engaged until you select
OFF. When you select OFF, the HVAC control module changes the
state of the A/C Permission parameter to Withheld and transmits a
clutch disable message to the PCM over the class 2 serial data circuit.

Air Inlet Door

Motor/Actuator
Tests

When you select ON, the HVAC control module commands the
recirculation actuator toward the maximum door position. The
actuator moves the door to the recirculation position. When you select
OFF, the HVAC control module commands the recirculation actuator
toward the minimum door position. The actuator moves the door to
the outside air position.

Blower Motor

Motor/Actuator
Tests

When you select ON, the HVAC control module commands the
blower motor to maximum speed. The blower motor operates at
maximum speed until you select OFF. The HVAC control module
must be in the ON state before selecting the output control.

HVAC
Actuator
Recalibration

-

When you select RESET, the HVAC control module recalibrates the
maximum and minimum door positions of each HVAC door. The
ambient air temperature display is set to the current value of the
Outside Air Temp. Raw parameter.

Inside Air

Motor/Actuator When you select OFF, the HVAC control module commands the

2004 Hummer H2

2004 HVAC HVAC Systems - Automatic - Hummer H2

PCM Scan Tool Output Controls

SCAN TOOL DATA LIST

BCM Scan Tool Data List

HVAC Control Module Scan Tool Data List

Temperature
Fan

Tests

inside air temperature fan OFF. The fan remains OFF until you select
ON. The normal state of the inside air temperature fan is ON.

Instant OAT
Update

Miscellaneous
Tests

The scan tool displays OFF or ON. This function updates the HVAC
control module ambient air temperature input to the current raw
value.

Left Mix
Motor

Motor/Actuator
Tests

When you select ON, the HVAC control module commands the left
air temperature actuator toward the maximum door position. The
actuator moves the door to the full hot position. When you select
OFF, the HVAC control module commands the left air temperature
actuator toward the minimum door position. The actuator moves the
door to the full cold position.

Mode 1 Door
Position

Motor/Actuator
Tests

When you select ON, the HVAC control module commands the mode
actuator toward the maximum door position. The actuator moves the
door to the panel position. When you select OFF, the HVAC control
module commands the mode actuator toward the minimum door
position. The actuator moves the door to the floor position.

Right Mix
Motor

Motor/Actuator
Tests

When you select ON, the HVAC control module commands the right
air temperature actuator toward the maximum door position. The
actuator moves the door to the full cold position. When you select
OFF, the HVAC control module commands the right air temperature
actuator toward the minimum door position. The actuator moves the
door to the full hot position.

Scan Tool

Output

Control

Additional

Menu

Selection(s)

Description

A/C Relay

Engine Output
Controls

The engine must be running and the PCM must receive an A/C request
from the HVAC control module in order to enable the output control. The
PCM de-energizes the A/C compressor clutch relay when you select OFF.
The relay remains de-energized until you select ON.

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Operating Conditions: Engine idling, A/C ON, ambient air temperature between 22-27° C (70-80°

F)

Left Solar Sensor

Data

Counts/Volts

Varies

Right Solar Sensor

Data

Counts/Volts

Varies

Scan Tool Parameter

Data List

Units Displayed

Typical Data

Value

Operating Conditions: Engine idling, A/C ON, ambient air temperature between 22-27° C (70-80°

2004 Hummer H2

2004 HVAC HVAC Systems - Automatic - Hummer H2

F)

A/C Switch

Input/Output

On/Off

Off

AC Permission

Input/Output

Withheld/Granted

Varies

Air Inlet Door Actual

Door

Positions

Counts

Varies

Air Inlet Commanded

Door

Positions

Counts

Varies

Air Inlet Motor Drive

Door

Positions

Stop, Increase, Decrease

Stop

Air Mix Door Left
Commanded

Door

Positions

Counts

Varies

Air Mix Door Right
Commanded

Door

Positions

Counts

Varies

Auto Switch

Input/Output

On/Off

Off

Battery Voltage

Input/Output

Volts

13.5-14.5 V

Blower Motor PWM Speed

Door

Positions

Percent

12-114%

Dim Level Requested

Sensor Data

Percent

Varies

Engine Coolant Temp

Sensor Data

° C/° F

Varies

Fan Down Button

Input/Output

On/Off

Off

Fan Up Button

Input/Output

On/Off

Off

Front Defrost Switch

Input/Output

On/Off

Off

Ign. Since Current DTC

Input/Output

Cycles

0

Inside Air Temp. Sensor

Sensor Data

° C/° F

Varies

Inside Air Temp. Fan

Sensor Data

On/Off

On

Left Mix Door Actual

Door

Positions

Counts

Varies

Left Mix Motor Drive

Door

Positions

Stop, Increase, Decrease

Stop

Left Temp. Setting

Input/Output

° C/° F

Varies

LH AC Duct Actual

Sensor Data

Counts

Varies

LH AC Duct Desired

Sensor Data

Counts

Varies

LH Heater Duct Actual

Sensor Data

Counts

Varies

LH Heater Duct Desired

Sensor Data

Counts

Varies

Mode Door Actual

Door

Positions

Counts

Varies

Mode Dr. Motor Command

Door

Positions

Counts

Varies

Mode Motor Drive

Door

Positions

Stop, Increase, Decrease

Stop

Mode Select Position

Door

Positions

Off, Auto, Defrost, Heater, Htr/Def, Bi-

Level, Panel

Varies

2004 Hummer H2

2004 HVAC HVAC Systems - Automatic - Hummer H2