GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2003 🢒 L300/LW300 🢒 DTC 🢒 DTC P0442

System Description

The evaporative emission (EVAP) system is used to store fuel vapors as to reduce the amount of unburned fuel from escaping into the atmosphere. The EVAP system consists of the EVAP canister, fuel tank pressure (FTP) sensor, EVAP lines and hoses, EVAP purge solenoid (normally closed), EVAP service port, EVAP vent solenoid (normally open) and fuel tank. The engine control module (ECM) monitors the EVAP system for circuit faults in the EVAP purge solenoid, EVAP vent solenoid and FTP sensor circuits. The ECM also monitors the EVAP system for leaks between EVAP vent and purge solenoid. When certain conditions have been met, the ECM will perform an EVAP diagnostic test. DTC P0442 will set if a vacuum decays too quickly during the EVAP diagnostic system test indicating a small EVAP system leak.

Conditions for Running the DTC

DTCs P0030, P0031, P0032, P0036, P0037, P0038, P0050, P0051, P0052, P0056, P0057, P0058, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0136, P0137, P0138, P0139, P0140, P0141, P0150, P0151, P0152, P0153, P0154, P0155, P0156, P0157, P0158, P0159, P0160, P0161, P0221, P0222, P0223, P0443, P0444, P0445, P0446, P0447, P0448, P0449, P0451, P0452, P0453, P0455, P0506, P0507, P1271, P1277, P1278, P1282, P1283, P1511, P1516, P1519, P1523, P1526, P1530, P1551, P2100, P2101, P2107, P2119, P2122, P2123, P2127, P2128, P2138, P2176 are not set.

    • The EVAP purge solenoid is commanded OFF.
    • The EVAP vent solenoid is commanded ON.
    • The engine is at idle.
    • The engine load is less than 35 percent.
    • The MAP is less than 40 kPa.
    • The battery voltage is greater than 11 volts.
    • The ECT at engine startup is between 8-75°C (46-167°F).
    • The IAT is between 8-75°C (46-167°F).
    • The long term FT cells learned (if not learned, engine must run longer than 16 minutes and 45 seconds).
    • The fuel level is between 6-48 L (1.6-12.7 gallons).

DTC P0442 diagnostic runs once per ignition cycle.

Conditions for Setting the DTC

The EVAP system can achieve vacuum, but a vacuum decay is detected during the diagnostic test.

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 DTC
    • 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 non-emission related diagnostic.
    • Clear the DTC with a scan tool.

Diagnostic Aids
    • If DTC P0440, 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 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 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 a 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 .

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

System OK