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Hummer H2. Manual - part 1565

intervals until the leak source has been located.

Did you locate and repair a leak source?

Go to Step

Go to Step 4

1. Disconnect the GE-41415-50 from the fuel fill

pipe.

2. Install the fuel fill cap to the fuel fill pipe.

3. Connect the J 41413-200 nitrogen/smoke supply

hose to the EVAP service port.

4. Use the remote switch to introduce smoke into

the EVAP system.

5. Inspect the entire EVAP system for exiting

smoke with the J 41413-SPT .

6. Continue to introduce smoke at 15 second

intervals until the leak source has been located.

Did you locate and repair a leak source?

Go to Step

Go to Step 5

1. Use the remote switch to stop introducing smoke.

2. Install the GE-41415-50 to the fuel fill pipe.

3. Connect the J 41413-200 nitrogen/smoke supply

hose and vehicle fuel fill cap to the GE-41415-
50 .

4. Command the EVAP canister vent solenoid valve

open with a scan tool.

5. Compare the fuel tank pressure sensor parameter

with a scan tool to theJ 41413-200
pressure/vacuum gauge.

Is the difference between the two gauges less than the
specified value?

1 in

H2O

Go to Step 6 Go to Step 12

1. Seal the EVAP system using the EVAP

Purge/Seal function with a scan tool.

2. Turn the nitrogen/smoke valve on the J 41413-

200 control panel to NITROGEN.

3. Use the J 41413-200 to pressurize the EVAP

system to the first specified value.

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

13 in

H2O

5 in

H2O

Go to Step 7 Go to Step 12

1. Stop introducing nitrogen into the EVAP system

with the remote switch.

2. Increase the EVAP canister purge solenoid valve

to 100 percent.

1 in

H2O

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

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

Go to

Diagnostic

Aids

Go to Step 8

Disconnect the EVAP purge pipe from the EVAP
canister purge solenoid valve.
Is the fuel tank pressure sensor parameter less than the
specified value?

1 in

H2O

Go to Step

Go to Step 9

Disconnect the EVAP purge pipe at the EVAP canister.
Is the fuel tank pressure sensor parameter less than the
specified value?

1 in

H2O

Go to Step

Go to Step 10

Disconnect the EVAP vapor pipe at the EVAP canister.
Is the fuel tank pressure sensor parameter less than the
specified value?

1 in

H2O

Go to Step

Go to Step 11

Repair the pinched or obstructed EVAP vapor pipe.
Did you complete the repair?

Go to Step

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

Go to Step

Replace the EVAP canister purge solenoid valve. Refer
to Evaporative Emission (EVAP) Canister Purge
Solenoid Valve Replacement .
Did you complete the replacement?

Go to Step

Repair the restriction in the EVAP purge pipe. Refer to
Evaporative Emission (EVAP) System Hoses/Pipes
Replacement (Engine Compartment EVAP Pipe) or
Evaporative Emission (EVAP) System Hoses/Pipes
Replacement (Chassis EVAP Pipe) or Evaporative
Emission (EVAP) System Hoses/Pipes Replacement
(EVAP Vent Pipe) or Evaporative Emission (EVAP)
System Hoses/Pipes Replacement (Rear EVAP Fuel
Tank Pipe) .
Did you complete the repair?

Go to Step

Replace the EVAP canister. Refer to Evaporative
Emission (EVAP) Canister Replacement .
Did you complete the replacement?

Go to Step

1. Connect the J 41413-200 to the fuel fill pipe.

2. Turn the nitrogen/smoke valve to NITROGEN.

3. Seal the EVAP system using the EVAP

Purge/Seal function with a scan tool.

4. Pressurize the EVAP system to the specified

IMPORTANT:

DO NOT exceed the specified value in this step.
Exceeding the specified value may produce
incorrect test results.

5 in

H2O

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 P0496

System Description

This DTC tests for undesired intake manifold vacuum flow to the evaporative emission (EVAP) system. The
control module seals the EVAP system by commanding the EVAP canister purge solenoid valve Closed and the
EVAP canister vent solenoid valve Closed. The control module monitors the fuel tank pressure (FTP) sensor to
determine if a vacuum is being drawn on the EVAP system. If vacuum in the EVAP system is more than a
predetermined value within a predetermined time, this DTC sets.

The following table illustrates the relationship between the ON and OFF states, and the Open or Closed states of
the EVAP canister purge and vent solenoid valves.

DTC P0496

Conditions for Running the DTC

DTCs P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0125,

value.

5. Observe the J 41413-200 pressure/vacuum gauge

for 5 minutes.

Does the J 41413-200 pressure/vacuum gauge remain
constant?

Go to Step

Go to Step 3

Observe the fuel tank pressure sensor parameter with a
scan tool.
Is the scan tool fuel tank pressure parameter within the
specified value of the J 41413-200 pressure/vacuum
gauge?

1 in

H2O

Go to Step

Go to Step 5

1. Observe the J 41413-200 pressure/vacuum

gauge.

2. Increase the EVAP canister purge solenoid valve

to 100 percent.

Does the pressure decrease?

Go to Step 19

Step

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

Control Module

Command

EVAP Canister Purge Solenoid

Valve

EVAP Canister Vent Solenoid

Valve

Open

Closed

OFF

Closed

Open

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

P0131, P0132, P0133, P0134, P0135, P0136, P0137, P0138, P0140, P0141, P0151, P0152, P0153,
P0154, P0155, P0156, P0157, P0158, P0160, P0161, P0220, P0442, P0443, P0449, P0452, P0453,
P0455, P0502, P0503, P1111, P1112, P1114, P1115, P1121, P1122, P1125, P2135 are not set.

The ignition voltage is between 10-18 volts.

The barometric pressure (BARO) is more than 75 kPa.

The fuel level is between 15-85 percent.

The engine coolant temperature (ECT) is between 4-30°C (39-86°F).

The intake air temperature (IAT) is between 4-30°C (39-86°F).

The start up ECT and IAT are within 9°C (16°F) of each other.

Conditions for Setting the DTC

A continuous open purge flow condition is detected during the diagnostic test.

The fuel tank pressure decreases to less than -11 inches H2O.

Action Taken When the DTC Sets

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

DTC P0496

Step

Action

Values

Yes

Schematic Reference: Emission Hose Routing Diagram

Did you perform the Diagnostic System
Check - Engine Controls?

Go to Step 2

Go to Diagnostic

System Check -

Engine Controls

1. Start the engine.

2. Seal the evaporative emission (EVAP)

system using the Purge/Seal function

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

Content .. 1563 1564 1565 1566 ..