Hummer H2. Manual - part 1561

4

1. Turn OFF the ignition.  

2. Connect the EVAP purge pipe.  

3. Connect the J 41413-200 Evaporative 

Emissions System Tester (EEST) power 
supply clips to a known good 12-volt 
source.  

4. Install the J 41415-40 Fuel Tank Cap 

Adapter or GE-41415-50 Fuel Tank Cap 
Adapter to the fuel fill pipe.  

5. Connect the fuel fill cap to the J 41415-40 or 

GE-41415-50 .  

6. Connect the J 41413-200 nitrogen/smoke 

supply hose to the J 41415-40 or GE-41415-
50 .  

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

8. Command the EVAP canister vent solenoid 

valve closed with a scan tool.  

9. Turn the nitrogen/smoke valve on the J 

41413-200 control panel to NITROGEN.  

10. Use the remote switch to pressurize the 

EVAP system to the first specified value.  

11. Observe the fuel tank pressure sensor in 

H2O with a scan tool.  

12. Command the EVAP canister vent solenoid 

valve open with a scan tool.  

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

5 in 

H2O 

1 in 

H2O

Go to Step 5

Go to Step 7

5

1. Connect the NITROGEN/SMOKE hose to 

the EVAP service port.  

2. Remove the J 41415-40 orGE-41415-50 .  

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

4. Start the engine.  

5. Allow the engine to idle.  

6. Use the PURGE/SEAL function to seal the 

system, with a scan tool.  

7. Command the EVAP canister purge 

solenoid valve to 30 percent.  

8. Observe the VACUUM/PRESSURE gauge 

on the J 41413-200 and the FTP parameter 
on the scan tool.  

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

  

9. Allow the vacuum to increase on the gauge 

of the J 41413-200 , until it reaches 
approximately 16 inches H2O.  

10. Use the PURGE/SEAL function to seal the 

system, with a scan tool.  

Is the difference between the FTP parameter on a 
scan tool and the VACUUM/PRESSURE gauge 
on the J 41413-200 within the specified value, 
until the vacuum reached the abort limit on a scan 
tool?

Go to Step 6

Go to Step 9

6

Did the FTP parameter on a scan tool display more 
than the specified value?

3.2 V

Go to 

Diagnostic 

Aids

Go to Step 12

7

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

1 in 

H2O

Go to Step 13

Go to Step 8

8

Disconnect the EVAP vent hose from the EVAP 
canister. 
Is the fuel tank pressure sensor parameter less than 
the specified value?

1 in 

H2O

Go to Step 11

Go to Step 14

9

Test for an intermittent and for a poor connection 
at the fuel tank pressure (FTP) sensor. 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 15

Go to Step 10

10

Test the low reference circuit of the FTP sensor for 
an open or high resistance. Refer to Circuit 
Testing and Wiring Repairs in Wiring Systems. 
Did you find and correct the condition?

-

Go to Step 15

Go to Step 12

11

Repair the pinched or restricted EVAP vent hose.
Did you complete the repair?

-

Go to Step 15

-

12

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

-

Go to Step 15

-

13

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

-

Go to Step 15

-

14

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

-

Go to Step 15

-

1. Turn OFF the ignition.  

 

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 P0449 

Circuit Description 

A battery positive is supplied to the evaporative emission (EVAP) canister vent solenoid valve. The control 
module grounds the EVAP canister vent solenoid valve control circuit to close the valve by means of an internal 
switch called a driver. The scan tool displays the commanded state of the EVAP canister vent solenoid valve as 
ON or OFF. The control module monitors the status of the driver. If the control module detects an incorrect 
voltage for the commanded state of the driver, this DTC sets.

15

2. Disconnect the purge line from the EVAP 

canister vent solenoid valve.  

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

Is the fuel tank pressure sensor parameter within 
the specified range?

-1 to +1 

in H2O

Go to Step 16

Go to Step 2

16

1. Turn OFF the ignition.  

2. Reconnect all disconnected components.  

3. Connect the J 41413-200 to the fuel fill 

pipe.  

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

5. Command the EVAP canister vent solenoid 

valve closed with a scan tool.  

6. Turn the nitrogen/smoke valve on the J 

41413-200 control panel to NITROGEN.  

7. Use the remote switch to pressurize the 

EVAP system to the first specified value.  

8. Observe the fuel tank pressure sensor in 

H2O with a scan tool.  

9. Command the EVAP canister vent solenoid 

valve open with a scan tool.  

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

IMPORTANT:

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

5 in 

H2O 

1 in 

H2O

Go to Step 17

Go to Step 2

17

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

 

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

  

The following table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED 
states of the EVAP canister vent solenoid valve. 

DTC P0449 

Conditions for Running the DTC 

z

The engine speed is more than 400 RPM.  

z

The system voltage is between 6-18 volts.  

Conditions for Setting the DTC 

z

The control module detects that the commanded state of the driver and the actual state of the control 
circuit do not match.  

z

The above conditions are present for a minimum of 5 seconds.  

Action Taken When the DTC Sets 

z

The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition 
cycle that the diagnostic runs and fails.  

z

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 

z

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

z

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

z

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

z

Clear the MIL and the DTC with a scan tool.  

Test Description 

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

2: Listen for a click when the valve operates. Verify that both the ON and the OFF states are commanded. 

5: This step verifies that the control module is providing ground to the EVAP canister vent solenoid 
valve.  

Control Module Command

EVAP Canister Vent Solenoid Valve Position

ON

CLOSED

OFF

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