Hummer H2. Manual - part 572

DTC B2425 OR B2430

Circuit Description

The driver and passenger seat heaters are controlled by the driver seat module. Power is supplied to the driver
seat cushion and back heater elements through individual voltage supply circuits. Power is supplied to the
passenger seat cushion and back heater elements through a common voltage supply circuit. All of the driver and
passenger seat heater elements are grounded by the driver seat module through individual low side drive control
circuits. The heater element control circuits are pulse width modulated to ground by the driver seat module in
order to control the seat temperatures by regulating the current flow through the heater elements.

Conditions for Running the DTC

The system voltage must be between 9.0-6.0 volts.

Conditions for Setting the DTC

The driver seat module determines by monitoring the heater element control circuits that a short to voltage,
short to ground, or open condition exists.

Action Taken When the DTC Sets

The heated seat with a current status DTC will be disabled.

Both heated seats may be disabled.

When the fault is no longer present a history status DTC will be stored, and heated seat operation will be
restored.

Conditions for Clearing the DTC

The DTC will be current for as long as the fault is present.

When the fault is no longer present the DTC will be a history status code.

The history DTC will be cleared after 100 error free ignition cycles, or by using the scan tool clearing
DTCs feature.

DTC B2425 or B2430

Does the DTC reset?

Go to Step 3

System OK

Step

Action

Values

Yes

Schematic Reference:Driver Seat Schematics , Passenger Seat Schematics
Connector End View Reference:Power Seat Systems Connector End Views

Did you perform the Power Seat Diagnostic
System Check?

Go to Step 2

Go to

Diagnostic

Starting Point

- Seats

Verify the fault is present.

Go to Testing for

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Seats - Hummer H2

Does the system operate normally?

Intermittent

Conditions and Poor

Connections in Wiring

Systems

Go to Step 3

1. Disconnect the driver seat module

connectors containing the voltage supply
and control circuits to the affected seat.

2. Using a DMM test for voltage at the heater

element control circuit terminals in the
harness connector. Refer to Circuit
Testing in Wiring Systems.

Is voltage present on either of the heater element
control circuits?

Go to Step 7

Go to Step 4

Using a DMM test for continuity to ground at the
heater element control circuit terminals in the
driver seat module harness connector. Refer to
Circuit Testing in Wiring Systems.
Is continuity to ground present on either of the
heater element control circuits?

Go to Step 8

Go to Step 5

Using a DMM measure the resistance through the
seat heater elements from the voltage supply
circuit terminal to each of the control circuit
terminals in the driver seat module harness
connector. Refer to Circuit Testing in Wiring
Systems.
Are the measurements within the specified
values?

1.5-5.5

ohm

Go to Step 10

Go to Step 6

Test the voltage supply and control circuits to the
affected heater element for an open or high
resistance. Refer to Circuit Testing and to
Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 13

Go to Step 9

Repair the voltage supply or control circuit to the
affected heater element for a short to voltage.
Refer to Circuit Testing and to Wiring Repairs
in Wiring Systems.
Is the repair complete?

Go to Step 13

Repair the voltage supply or control circuit to the
affected heater element for a short to ground.
Refer to Circuit Testing and to Wiring Repairs
in Wiring Systems.
Is the repair complete?

Go to Step 13

Inspect for poor connections at the heater element
connectors. Refer to Testing for Intermittent
Conditions and Poor Connections and to

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Seats - Hummer H2

DTC B2435 OR B2440

Circuit Description

The driver seat module relies on inputs from thermistors installed in the driver and passenger seat backs to
control heated seat temperatures. The thermistors are 2 wire sensors supplied with a 5-volt referenced signal
circuit and low reference circuit from the driver seat module. Resistance through the thermistors varies with
temperature causing the heated seat sensor signal circuit voltage levels to decrease as the seat back temperatures
rise.

Conditions for Running the DTC

The system voltage must be between 9.0-16.0 volts.

The heated seat is in an active state.

Conditions for Setting the DTC

The heated seat sensor signal circuit voltage to the driver seat module is greater than 4.94 volts for 30
seconds or more.

The heated seat sensor signal circuit voltage to the driver seat module is less than .078 volts for 30
seconds or more.

The heated seat sensor signal circuit input to the driver seat module indicates that the desired seat
temperature has not been reached within 30 minutes after activation.

Action Taken When the DTC Sets

Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 13

Go to Step 11

Inspect for poor connections at the driver seat
module connectors. Refer to Testing for
Intermittent Conditions and Poor Connections
and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 13

Go to Step 12

Replace the affected seat heater element.
Is the repair complete?

Go to Step 13

Replace the driver seat module. Refer to
Memory Seat Control Module Replacement .
Is the repair complete?

Go to Step 13

1. Use the scan tool in order to clear the

DTCs.

2. Operate the vehicle within the Conditions

for Running the DTC.

Does the DTC reset?

Go to Step 3

System OK

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Seats - Hummer H2

The heated seat with a current status DTC will be disabled.

When the fault is no longer present a history status DTC will be stored, and heated seat operation will be
restored.

Conditions for Clearing the DTC

The DTC will be current for as long as the fault is present.

When the fault is no longer present the DTC will be a history status code.

The history DTC will be cleared after 100 error free ignition cycles, or by using the scan tool clearing
DTCs feature.

Test Description

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

3: Tests for the proper operation of the circuit in the high voltage range.

4: Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens
upon performing this test, the signal circuit has a short to voltage.

DTC B2435 or B2440

Step

Action

Values

Yes

Schematic Reference:Driver Seat Schematics , Passenger Seat Schematics
Connector End View Reference:Power Seat Systems Connector End Views

Did you perform the Power Seat Diagnostic
System Check?

Go to Step 2

Go to Diagnostic

System Check -

Power Seat

Systems

1. Install a scan tool.

2. Start the engine.

3. Turn the heated seat ON.

4. With a scan tool, observe the Heated

Seat Sensor parameter in the data list
for the driver seat module.

Does the scan tool indicate that the Heated
Seat Sensor parameter is within the specified
range?

0.078-

4.94 V

Go to Testing for

Intermittent

Conditions and Poor

Connections in Wiring

Systems

Go to Step 3

1. Turn OFF the ignition.

2. Disconnect the heated seat back 4-way

connector.

3. Start the engine.

4. Turn the heated seat ON.

4.5 V

2004 Hummer H2

2004 ACCESSORIES & EQUIPMENT Seats - Hummer H2

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