GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2004 🢒 L300/LW300 🢒 DTC 🢒 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 from the exhaust system 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. With the EVAP system sealed, this 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 P0117, P0118, P0125, P0128, P0443, P0446, P0449, P0451, P0452, P0453, P0455, P0458, P0459, P0498, P0499, P0502, P0560, P0562, P0563 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) less than 10° C (50°F).
    • The start up engine coolant temperature (ECT) is less than 40°C (104°F).
    • The start up IAT and ECT are within 8°C (15°F).
    • The barometric pressure (BARO) is more than 68 kPa.
    • The ambient air temperature is between 2-40°C (36-104°F).
    • The engine run time minimum is 10 minutes.
    • The odometer displays more than 10 miles.
    • The vehicle has traveled more than 20 km (12.5 miles) this trip.
    • The ECT is more than 70°C (158°F).
    • The fuel level is between 15-85 percent.
    • The battery voltage is more than 11 volts
    • The ignition is OFF.
    • The fuel level change with the ignition OFF is less than 10 percent.

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
    • If DTC P0442, P0446, P0455 is set, EVAP special functions on the scan tool will not be allowed. Clear DTCs before performing these tests.
    • The ECM uses the FTP sensor to detect the pressure of fuel vapor in the fuel tank during all parts of the EVAP diagnostic system test. Ensure the FTP sensor is not skewed by verifying FTP SENSOR on the scan tool is between 2.35-2.85 volts with the ignition ON and the engine OFF, with the fuel cap removed.
    • Possible causes of a small EVAP leak:
    • The fuel cap is leaking.
    • The EVAP canister vent solenoid valve stuck open.
    • The EVAP service port valve is leaking.
    • The EVAP line/hose connections are disconnected/leaking.
    • The fuel sender O-ring is leaking.
    • The FTP sensor seal is leaking.
    • To help locate intermittent leaks, use the J 41413-200 (J 41413-100) Evaporative Emissions System Tester (EEST) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with a High Intensity White Light.
    • To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the High Intensity White Light.
    • Review the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to set occurs. This may assist in diagnosing the condition.
    • For intermittent conditions refer to Intermittent Conditions .

Test Description

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

  1. 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.

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

Step

Action

Yes

No

Schematic Reference: Evaporative Emissions Hose Routing Diagram

1

Did you perform the Diagnostic System Check - Vehicle?

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 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 (J 41413-100) Evaporative Emissions System Tester (EEST).
  3. Use the remote switch to activate the J 41413-200 (J 41413-100).
  4. Align the red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the J 41413-200 (J 41413-100).
  5. Install the J 41415-40 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 .
  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 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 (J 41413-100) power supply clips to a known good 12-volt source.
  3. Install the J 41415-40 to the fuel fill pipe.
  4. Connect the fuel fill cap to the J 41415-40 .
  5. Connect the J 41413-200 (J 41413-100) nitrogen/smoke supply hose to the J 41415-40 .
  6. Turn ON the ignition with the engine OFF.
  7. Command the EVAP canister vent solenoid valve closed with a scan tool.
  8. Turn the nitrogen/smoke valve on the J 41413-200 (J 41413-100) control panel to SMOKE.
  9. Use the remote switch to introduce smoke into the EVAP system.
  10. Use the J 41413-VLV EVAP Service Port Vent Fitting to open the EVAP service port.
  11. Remove the J 41413-VLV once smoke is observed.
  12. Continue to introduce smoke into the EVAP system for an additional 60 seconds.
  13. Inspect the entire EVAP system for exiting smoke with a High Intensity White Light.
  14. 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 from the fuel fill pipe.
  2. Install the fuel fill cap to the fuel fill pipe.
  3. Connect the J 41413-200 (J 41413-100) 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 a High Intensity White Light.
  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

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 0.5 mm (0.20 in) test orifice on the bottom-front of the J 41413-200 (J 41413-100).
  3. Use the remote switch to activate the J 41413-200 (J 41413-100).
  4. Align the red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the J 41413-200 (J 41413-100).
  5. Install the J 41415-40 to the fuel fill pipe.
  6. Remove the nitrogen/smoke hose from the test orifice and install the hose onto the J 41415-40 .
  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 - Vehicle in Vehicle DTC Information

System OK