Regarding Code P0442 on 04 Sierra

[KyRob]

My check engine light is still on and I have been reading about the problem and checked the gas cap like was suggested on here. I have read several places that if the EVAP vent was bad, it would shut off the pump when filling the tank. Mine takes gas like it always has and only shuts off when full. Does this mean the EVAP vent is good or can it still be bad? What else can I check before buying the solenoid kit and replacing? There is a hose coming from the top of the tank and it goes to the gas cap door and feels like a filter of some sort on the end. I haven't got a good look at it but that's what it feels like. Is this part of the evap system?

 

Thanks for any ideas,

 

Rob

[SILVERADOSC540]

Wish I had an answer for you. Somebody probably will. Did you post in the tech section?

[gmtech4]

you cant do this at home Rob....take it in or drive it ,,,DO NOT THROW PARTS AT IT

 

DTC P0442

 

System Description

 

This diagnostic tests the evaporative emission (EVAP) system for a small leak when the key is turned OFF and the correct conditions are met.

Heat is transferred into a vehicle fuel tank while the vehicle is operating. When the vehicle is turned OFF, a change in the fuel tank vapor temperature occurs, which results in corresponding pressure changes in the fuel tank vapor space. This change is monitored by the control module using the fuel tank pressure sensor input. The control module then makes a judgement on the integrity of the system. With a 0.51?mm (0.020?in) leak in the system, the amount of pressure change observed is significantly less than that of a sealed system.

If the control module detects a pressure change less than a calibrated amount, DTC?P0442 sets.

Conditions for Running the DTC

 

 

• DTCs?P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0125, P0335, P0336, P0443, P0446, P0449, P0452, P0453, P0455, P0496, P0500, P0502, P1106, P1107, P2610 are not set.

 

 

 

• The diagnostic runs once with a 10?hour minimum between tests after a fail.

 

 

 

• DTC?P0455 must run and pass.

 

 

 

• The start up intake air temperature (IAT) is between 4–30°C (39–86°F).

 

 

 

• The start up engine coolant temperature (ECT) is less than 30°C (86°F).

 

 

 

• The start up IAT and ECT are within 8°C (15°F).

 

 

 

• The barometric pressure (BARO) is more than 74?kPa.

 

 

 

• The ambient air temperature is between 2–32°C (36–90°F).

 

 

 

• The engine run time minimum is 600?seconds.

 

 

 

• The odometer displays more than 10?miles.

 

 

 

• The vehicle has traveled more than 3?miles this trip.

 

 

 

• The ECT is more than 70°C (158°F).

 

 

 

• The fuel level is between 15–85?percent.

 

 

 

• The ignition is OFF.

 

Conditions for Setting the DTC

 

The control module detects a pressure change that is less than a calibrated amount.

Action Taken When the DTC Sets

 

 

• The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.

 

 

 

• The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/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.

 

Diagnostic Aids

 

 

• To help locate intermittent leaks, use the

J 41413-200 Evaporative Emissions System Tester (EEST) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the GE-41413-SPT High Intensity White Light.

 

 

 

• A condition may exist where a leak in the EVAP system only exists under a vacuum condition. By using the scan tool PURGE/SEAL function to create a vacuum, seal the system and observe the FTP parameter for vacuum decay, this type of leak may be detected.

 

 

 

• To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the

GE-41413-SPT .

 

 

 

• For intermittent conditions, refer to

Intermittent Conditions .

 

Test Description

 

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

3 Introducing smoke in 15?second intervals may allow smaller leak areas to be more noticeable. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.

 

 

5 This step verifies that repairs are complete and that no other condition is present.

 

Step

 

 

 

Action

 

 

 

Yes

 

 

 

No

 

 

 

Schematic Reference: Emission Hose Routing Diagram

 

 

1

 

 

Did you perform the Diagnostic System Check–Engine Controls?

 

 

Go to Step?2

 

 

Go to Diagnostic System Check - Engine Controls

 

 

2

 

 

Important: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.

 

 

1. Turn the nitrogen/smoke valve to nitrogen.

 

 

2. Connect the nitrogen/smoke hose to the 0.5?mm (0.20?in) test orifice on the bottom-front of the

J 41413-200 Evaporative Emissions System Tester (EEST).

 

 

3. Activate the

J 41413-200 with the remote switch.

 

 

4. Align the red flag on the flow meter with the floating indicator. De-activate the

J 41413-200 with the remote switch.

 

 

5. Install the

J 41415-40 Fuel Tank Cap Adapter or GE-41415-50 Fuel Tank Cap Adapter to the fuel fill pipe.

 

 

6. Remove the nitrogen/smoke hose from the test orifice and install the hose onto the

J 41415-40 or GE-41415-50 .

 

 

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

 

 

8. Command the evaporative emissions (EVAP) canister vent solenoid valve closed with a scan tool.

 

 

9. Introduce nitrogen and fill the EVAP system until the floating stabilizes with the remote switch.

 

 

10. Compare the flow meter's stable floating indicator position to the red flag.

 

Is the floating indicator below the red flag?

 

 

Go to Diagnostic Aids

 

 

Go to Step?3

 

 

3

 

 

Important: Ensure that the vehicle underbody temperature is similar to the ambient temperature and allow the surrounding air to stabilize before starting the diagnostic procedure. System flow will be less with higher temperatures.

 

 

1. Turn OFF the ignition.

 

 

2. Connect the

J 41413-200 power supply clips to a known good 12-volt source.

 

 

3. Install the

J 41415-40 or GE-41415-50 to the fuel fill pipe.

 

 

4. Connect the

J 41413-200 nitrogen/smoke supply hose to the J 41415-40 or GE-41415-50 .

 

 

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

 

 

6. Command the EVAP canister vent solenoid valve closed with a scan tool.

 

 

7. Turn the nitrogen/smoke valve on the

J 41413-200 control panel to SMOKE.

 

 

8. Use the remote switch to introduce smoke into the EVAP system.

 

 

9. Use the

J 41413-VLV EVAP Service Port Vent Fitting to open the EVAP service port.

 

 

10. Remove the

J 41413-VLV once smoke is observed.

 

 

11. Continue to introduce smoke into the EVAP system for an additional 60?seconds.

 

 

12. Inspect the entire EVAP system for exiting smoke with the

GE-41413-SPT High Intensity White Light.

 

 

13. 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?5

 

 

Go to Step?4

 

 

4

 

 

 

 

1. Disconnect the

J 41415-40 or 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

GE-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?5

 

 

Go to Diagnostic Aids

 

 

<a href="http://gsi.xw.gm.com/newsi/showDoc.do?laborOpCode=&docSyskey=1251038&cellId=30494&pubObjSyskey=4432531&from=sm&pubCellSyskey=431873#td05">5

 

 

Important: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize.

 

 

1. Turn the nitrogen/smoke valve to nitrogen.

 

 

 

2. Connect the nitrogen/smoke hose to the 0.50?mm (0.20?in) test orifice on the bottom-front of the

J 41413-200 .

 

 

 

3. Use the remote switch to activate the

J 41413-200 .

 

 

 

4. Align the red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the

J 41413-200 .

 

 

 

5. Install the

J 41415-40 or GE-41415-50 to the fuel fill pipe.

 

 

 

6. Remove the nitrogen/smoke hose from the test orifice and install the hose onto 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. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating stabilizes.

 

 

 

10. Compare the flow meter's stable floating indicator position to the red flag.

 

 

Is the floating indicator below the red flag?

 

 

Go to Step?6

 

 

Go to Step?2

 

 

6

 

 

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

[KyRob]

Well, it's fixed. A guy at work said his wifes GM product had the engine light come on a lot. He would tighten the gas cap and he said it would sometimes take 4 to 5 hundred miles of driving before it would go off. I just kept driving it and I started it up Friday evening and it was gone and hasn't come back on. Anyway, glad it's gone and thanks for all the responses.

 

Rob