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Hummer H2. Manual - part 1663

Information.

3. Disconnect the fuel tank wiring harness at the

fuel tank harness connector.

4. Connect a 3-amp fused jumper wire between

the 5-volt reference circuit of the FTP sensor
and the signal circuit of the FTP sensor.

5. Turn ON the ignition, with the engine OFF.

6. Observe the fuel tank pressure sensor voltage

with a scan tool.

Is the fuel tank pressure sensor parameter more than
the specified value?

4.8 V

Go to Step 8

Go to Step 6

Test the 5-volt reference circuit of the FTP sensor for
an open between the fuel tank harness connector and
the control module. Refer to Circuit Testing and
Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 12

Go to Step 7

Test the signal circuit of the FTP sensor for a short to
ground, or an open between the fuel tank harness
connector and the control module. Refer to Circuit
Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 12

Go to Step 9

1. Remove the fuel tank. Refer to Fuel Tank

Replacement .

2. Inspect the fuel tank wiring harness for the

following:

Damaged wiring

Poor connections

Broken wires inside the insulation-Refer
to Circuit Testing and Wiring Repairs
in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 10

Inspect for poor connections at the harness connector
of the control module. Refer to Testing for
Intermittent Conditions and Poor Connections and
Connector Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 12

Go to Step 11

Replace the FTP sensor. Refer to Fuel Tank
Pressure Sensor Replacement .
Did you complete the replacement?

Go to Step 12

Replace the control module. Refer to Powertrain
Control Module (PCM) Replacement .
Did you complete the replacement?

Go to Step 12

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0171/P0174 To DTC P0507 (TAC)) - 4.8L, 5.3L, and

6.0L - Hummer H2

DTC P0453

Circuit Description

The fuel tank pressure (FTP) sensor measures the difference between the air pressure or vacuum in the
evaporative emission (EVAP) system, and the outside air pressure. The control module supplies a 5-volt
reference and a low reference circuit to the FTP sensor. The FTP sensor signal circuit voltage varies depending
on EVAP system pressure or vacuum. If the FTP sensor signal voltage increases above a calibrated value, this
DTC sets.

The following table illustrates the relationship between FTP sensor signal voltage and the EVAP system
pressure/vacuum.

DTC P0453

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

The fuel tank pressure (FTP) sensor voltage is more than 4.9 volts.

All conditions are present for more than 5 seconds.

Action Taken When the DTC Sets

The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition

1. Observe the Freeze Frame/Failure Records for

this DTC.

2. Turn OFF the ignition for 30 seconds.

3. Turn ON the ignition, with the engine OFF.

4. Operate the vehicle within the Conditions for

Running the DTC. You may also operate the
vehicle within the conditions that you observed
from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 13

Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?

Go to

Diagnostic

Trouble Code

(DTC) List

System OK

FTP Sensor Signal Voltage

Fuel Tank Pressure

High, Approximately 1.5 Volts or More

Negative Pressure/Vacuum

Low, Approximately 1.5 Volts or Less

Positive Pressure

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0171/P0174 To DTC P0507 (TAC)) - 4.8L, 5.3L, and

6.0L - Hummer H2

cycle that the diagnostic runs and fails.

The control module records the operating conditions at the time the diagnostic fails. The first time the
diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic
reports a failure on the second consecutive ignition cycle, the control module records the operating
conditions at the time of the failure. The control module writes the operating conditions to the Freeze
Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles
that the diagnostic runs and does not fail.

A current DTC, Last Test Failed, clears when the diagnostic runs and passes.

A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other
emission related diagnostic.

Clear the MIL and the DTC with a scan tool.

Test Description

The number below refers to the step number on the diagnostic table.

2: If DTC P0641 or P0651 is set, the 5-volt reference circuit may be shorted to a voltage.

DTC P0453

Step

Action

Values

Yes

Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls Connector End Views or Powertrain Control
Module (PCM) Connector End Views

Did you perform the Diagnostic System Check-
Engine Controls?

Go to Step 2

Go to Diagnostic

System Check -

Engine Controls

1. Idle the engine for 1 minute.

2. Monitor the diagnostic trouble code (DTC)

information with the scan tool.

Did DTC P0641 or P0651 fail this ignition?

Go to

Diagnostic

Trouble Code

(DTC) List

Go to Step 3

1. Turn ON the ignition, with the engine OFF.

2. Observe the fuel tank pressure sensor voltage

with a scan tool.

Is the fuel tank pressure sensor parameter more than
the specified value?

4.3 V

Go to Step 5

Go to Step 4

1. Observe the Freeze Frame/Failure Records for

this DTC.

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0171/P0174 To DTC P0507 (TAC)) - 4.8L, 5.3L, and

6.0L - Hummer H2

2. Turn OFF the ignition for 30 seconds.

3. Turn ON the ignition, with the engine OFF.

4. Operate the vehicle within the Conditions for

Running the DTC. You may also operate the
vehicle within the conditions that you
observed from the Freeze Frame/Failure
Records.

Did the DTC fail this ignition?

Go to Step 5

Go to Intermittent

Conditions

1. Turn OFF the ignition.

2. Raise and support the vehicle. Refer to Lifting

and Jacking the Vehicle in General
Information.

3. Disconnect the fuel tank wiring harness at the

fuel tank harness connector.

4. Turn ON the ignition, with the engine OFF.

5. Observe the fuel tank pressure sensor voltage

with a scan tool.

Does the scan tool indicate that the fuel tank
pressure sensor parameter is more than the specified
value?

1 V

Go to Step 6

Go to Step 7

Test the signal circuit of the FTP for a short to
voltage between the fuel tank harness connector and
the control module. Refer to Circuit Testing and
Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 13

Go to Step 12

Probe the low reference circuit of the FTP sensor at
the fuel tank harness connector with a test lamp
connected to battery voltage. Refer to Circuit
Testing in Wiring Systems.
Did the test lamp illuminate?

Go to Step 9

Go to Step 8

Test the low reference circuit of the FTP sensor for
an open between the fuel tank harness connector and
the control module. Refer to Circuit Testing and
Wiring Repairs in Wiring Systems.
Did you find and correct the condition?

Go to Step 13

Go to Step 10

1. Remove the fuel tank. Refer to Fuel Tank

Replacement .

2. Disconnect the FTP sensor harness connector.

3. Inspect the fuel tank wiring harness for the

following:

Damaged wiring

2004 Hummer H2

2004 ENGINE PERFORMANCE Engine Controls Diagnosis (DTC P0171/P0174 To DTC P0507 (TAC)) - 4.8L, 5.3L, and

6.0L - Hummer H2

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