GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2003 🢒 L200/LW200 🢒 DTC 🢒 DTC P0442

System Description

The evaporative emission (EVAP) system is used to store fuel vapors to reduce the amount of unburned fuel from escaping into the atmosphere. The EVAP system consists of the EVAP canister, the fuel tank pressure (FTP) sensor, the EVAP lines and hoses, the EVAP canister purge solenoid valve which is normally closed, the EVAP service port, the EVAP canister vent solenoid valve which is normally open, the fuel tank, and the powertrain control module (PCM). The PCM monitors the EVAP system for circuit faults in the FTP sensor, the EVAP canister purge solenoid valve and the EVAP canister vent solenoid valve circuits. The PCM also monitors the EVAP system for small and large leaks. During the EVAP diagnostic, the PCM monitors the FTP sensor for an atmospheric pressure reading when all of the DTC parameters have been met with the engine running. The PCM will then command the EVAP canister vent solenoid valve ON, closed valve, and command the EVAP canister purge solenoid valve to a fixed duty cycle. The PCM will let the pressure drop in the fuel tank for a certain length of time, after which it will turn OFF the EVAP canister purge solenoid valve. If a correct amount of vacuum is achieved, the PCM will run the DTC P0442 diagnostic, which will monitor the decay in the vacuum of the sealed system over a calibrated amount of time. DTC P0442 sets when the vacuum decay is greater than the calibrated amount for a certain length of time due to a small leak.

Conditions for Running the DTC
    • DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0135, P0452, P0453, P0502, P0503, P0601, P0602, P1621 are not set.
    • The EVAP canister vent solenoid valve is commanded ON, closed.
    • The EVAP canister purge solenoid valve is commanded OFF, closed.
    • The engine is running.
    • The fuel level is between 15-85 percent.
    • The barometric pressure (BARO) is greater than 75 kPa.
    • The engine coolant temperature (ECT) and the intake air temperature (IAT) are between 4-30°C (39-86°F) at engine startup.
    • The ECT and the IAT are within 8°C (15°F) of each other.
    • The throttle position (TP) angle is between 7-35 percent.
    • The vehicle speed is less than 113 km/h (70 mph).
    • The DTC P0442 diagnostic runs once per ignition cycle after the above conditions have been met.

Conditions for Setting the DTC
    • If the vacuum decay is greater than 0.02 volts with low fuel level and 0.10 volts with high fuel level, FTP sensor volts per second indicating a small EVAP leak, DTC P0442 will set.
    • The above condition exists longer than 15 seconds.

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
    • An EVAP canister purge solenoid valve or EVAP canister vent solenoid valve circuit fault may have caused this DTC to set.
    • The PCM uses the FTP sensor to detect the amount of vacuum pulled on the EVAP system during the leak diagnostic tests. Ensure that the fuel pressure sensor is not skewed by verifying the FTP sensor on the scan tool is between 2.35-2.85 volts with the ignition ON and the fuel cap removed.
    • Locate the small leak with the Evaporative Emission System Tester (EEST).
    • The following are possible causes of a small leak:
       - The fuel cap is leaking.
       - The EVAP canister vent solenoid valve is not seating correctly.
       - The EVAP vent hose is loose or damaged.
       - The EVAP canister is leaking.
       - The fuel sender assembly O-ring is leaking.
       - The fuel tank or filler neck is leaking.
    • The small leak diagnostic can detect a leak greater than 0.020 of an inch in diameter.
    • 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.

Step

Action

Yes

No

Schematic Reference: Evaporative Emissions 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 stabilizer.

  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 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) Evaporative Emissions System Tester (EEST) power supply clips to a known good 12-volt source.
  3. Install the J 41415-40 Fuel Tank Cap Adapter 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 millimeter (0.20 inch) 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

System OK