Hummer H3. Manual — part 1646

The SERVICE 4WD indicator will remain illuminated for the remainder of the current ignition
cycle.

Conditions for Clearing the DTC

The transfer case shift control module will clear the DTC if the condition for setting the
DTC is not currently present.

A history DTC will clear after 33 consecutive ignition cycles without a fault present.

History DTCs can be cleared using a scan tool.

Test Description

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

2: This step tests for voltage at the ignition 3 voltage side of the transfer case select switch.

3: This step tests the control circuit of the Neutral indicator for a short to voltage or an
open.

4: This step tests the control circuit of the Neutral indicator for a short to ground.

DTC B0790

Step

Action

Yes

No

Schematic Reference: Transfer Case Control Schematics
Connector End View Reference: Transfer Case Control Connector End Views

1

Did you perform the Diagnostic System
Check - Vehicle?

Go to Step 2

Go to
Diagnostic
System Check
- Vehicle

2

1. Turn the ignition OFF.

2. Remove the transfer case select switch.

3. Disconnect the connector on the transfer

case select switch.

4. Turn the ignition ON.

5. Probe the Ignition 3 voltage circuit with

a DMM that is connected to a good
ground.

Does the DMM indicate battery voltage?

Go to Step 3

Go to Step 6

Test the Neutral indicator control circuit for a

2007 Hummer H3

2007 TRANSMISSION Transfer Case - BW 4493/4494 - H3

DTC B2725

3

short to voltage or an open. Refer to Circuit
Testing
and Wiring Repairs .
Did you find and correct the condition?

Go to Step 9

Go to Step 4

4

Test the control circuit of the Neutral
indicator for a short to ground. Refer to
Testing for Short to Ground and Wiring
Repairs
.
Did you find and correct the condition?

Go to Step 9

Go to Step 5

5

Inspect for poor connections at the harness
connector of the transfer case shift control
module and the transfer case shift control
switch. Refer to Testing for Intermittent
Conditions and Poor Connections

andConnector Repairs .
Did you find and correct the condition?

Go to Step 9

Go to Step 7

6

Test the Neutral feed circuit of the transfer
case select switch for an open, high resistance
or short to ground. Refer to Circuit Testing
and Wiring Repairs .
Did you find and correct the condition?

Go to Step 9

-

7

Replace the transfer case select switch and
clear all DTCs. Refer to Transfer Case
Shift Control Switch Replacement
.
Does the DTC reset?

Go to Step 8

System OK

8

Replace the transfer case shift control
module. Refer to Control Module
References
for replacement, setup and
programming.
Did you complete the repair?

Go to Step 9

-

9

1. Use the scan tool in order to clear the

DTCs.

2. Operate the vehicle within the

Conditions for Running the DTC as
specified in the supporting text.

Does the DTC reset?

Go to Step 1

System OK

2007 Hummer H3

2007 TRANSMISSION Transfer Case - BW 4493/4494 - H3

Circuit Description

The mode switch circuit consists of 5 modes. The transfer case shift control module supplies a
regulated 5 volts, DC to the switch through the 5-volt regulator circuit. The current travels
through the resistor of the currently pressed mode button. The current is then returned to the
transfer case shift control module through the switch signal circuit.

The transfer case shift control module constantly monitors this signal voltage to determine the
condition of the mode switch circuit.

When each of the modes are selected they will complete a circuit through their own specific
resistor while the button is pressed. The transfer case shift control module continuously monitors
the switch input to determine whether the Neutral, Differential Lock, 4HI, 4HI Lock or 4LO
Lock mode was selected by the driver.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B2725 ATC Mode Switch Circuit Malfunction

Conditions for Running the DTC

The ignition is ON.

The system voltage is 9-18 volts.

Conditions for Setting the DTC

The system constantly monitors the voltage on switch signal circuit.

If the system detects a voltage level under 0.3 volt or greater than 0.75 volts for 60 seconds,
the DTC is logged.

Action Taken When the DTC Sets

All shifting will be disabled.

The SERVICE 4WD indicator will remain illuminated for the remainder of the current
ignition cycle.

Conditions for Clearing the DTC

The transfer case shift control module will clear the current DTC if the condition for setting
the DTC is not currently present.

2007 Hummer H3

2007 TRANSMISSION Transfer Case - BW 4493/4494 - H3

A history DTC will clear after 33 consecutive ignition cycles without a fault present.

History DTCs can be cleared using a scan tool.

Test Description

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

2: This step tests for proper operation of the transfer case mode select switch.

3: This step tests the mode switch for proper resistance values in all mode switch states.

4: This step tests for proper voltage on the 5-volt reference circuit.

5: This step tests the 5-volt reference circuit for an open, high resistance, short to voltage or
short to ground.

6: This step tests the switch signal circuit for an open, high resistance, short to voltage or
short to ground.

DTC B2725

Step

Action

Values

Yes

No

Schematic Reference: Transfer Case Control Schematics
Connector End View Reference: Transfer Case Control Connector End Views

1

Did you perform the Diagnostic
System Check - Vehicle?

-

Go to Step 2

Go to
Diagnostic
System
Check -
Vehicle

2

1. Install a scan tool.

2. Start the engine.

3. Set the Park brake.

4. Place the transmission into

Neutral.

5. With a scan tool, observe the

Mode Switch Selected
parameter.

6. Select each of the modes.

Does the scan tool indicate that the
transfer case is in the mode that is
selected?

-

Go to Testing
for
Intermittent
Conditions
and Poor
Connections

Go to Step 3

2007 Hummer H3

2007 TRANSMISSION Transfer Case - BW 4493/4494 - H3

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Текст

Политика конфиденциальности