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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1387 (Engine Control System Diagnosis (DTC P0130 To DTC P0456) -- 1.8L (LV6)) >> Diagnosis >> DTC P0442 >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.

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

  1. 3:  This step verifies that the DTC P0442 is captured in the freeze frame/failure record list. When multiple EVAP system DTCs are set, the DTC stored in the freeze frame/failure record is the best diagnostic starting point.
  2. 5:  This test verifies that the EVAP purge solenoid is electrically functional.
  3. 6:  This test verifies that the EVAP vent solenoid is electrically functional.
  4. 7:  This test verifies that the EVAP pressure switching solenoid is electrically functional
  5. 14:  The fuel filler pipe has two vent lines that allow for recirculation of fuel vapors between the fuel filler pipe and the fuel tank. Because of these vent lines the EEST can be connected to the EVAP service port for leak detection. Waiting until smoke is seen before plugging the EVAP canister drain hose speeds up the filling of the canister with smoke. Introducing smoke in between 60 second intervals of Nitrogen will speed up the filling of smoke in the fuel tank and filler pipe vapor space. This occurs because the pressure at which Nitrogen gas is applied is greater than the pressure at which smoke is introduced. The Nitrogen gas pushes the smoke that was just introduced through the canister and into the fuel tank. The EVAP vent solenoid DOES NOT have to be turned ON in order to test for leaks. A one way check valve located in the vent port of the EVAP canister provides containment of smoke and pressure within the EVAP system.
  6. 15:  This test verifies that the fuel tank pressure (FTP) sensor is accurate. An FTP sensor that does not correctly respond to vacuum, or pressure may cause this DTC to set.
  7. 17:  This step tests the functional operation of the EVAP pressure switching solenoid.
  8. 21:  This step tests the functional operation of the EVAP vent solenoid.
  9. 22:  This step tests the functional operation of the EVAP vent solenoid.
  10. 23:  This step tests the functional operation of the EVAP purge solenoid.
DTC P0442

Step Action Values Yes No
Schematic Reference:  Engine Controls Schematics 
Connector End View Reference:  Powertrain Control Module (PCM) Connector End Views  or  Engine Controls Connector End Views 
1 Did you perform the Diagnostic System Check-Engine Controls? - Go to Step 2  Go to Diagnostic System Check - Engine Controls
2
  1. Install a scan tool.
  2. Check for DTCs.
Is a DTC P0450, P0451, P0452, or P0453 present?		 - Go to DTC P0450 DTC P0451 DTC P0452 DTC P0453  Go to Step 3 
3 
  1. Review the Freeze Frame/Failure Records.
  2. Diagnose the DTC captured in the Freeze Frame/Failure records first.
Is DTC P0442 captured in the Freeze Frame/Failure records?		 - Go to Step 4  Go to Diagnostic Trouble Code (DTC) List
4
  1. Inspect the EVAP system for the following conditions:
    • A loose, missing, or damaged service port schrader valve
    • A loose, incorrect, missing, or damaged fuel fill cap
    • A damaged EVAP purge solenoid
  2. Raise the vehicle on a hoist. Refer to Lifting and Jacking the Vehicle in General Information.
  3. Inspect the EVAP system for the following conditions:
    • Any disconnected, improperly routed, kinked, or damaged EVAP pipes and hoses
    • A damaged EVAP vent solenoid or EVAP canister
Did you find and correct the condition?		 - Go to Step 44  Go to Step 5 
5  Command the EVAP purge solenoid ON and OFF with the scan tool.
Do you hear or feel a click as the EVAP purge solenoid is commanded ON and OFF?		 - Go to Step 6  Go to Step 8 
6  Command the EVAP vent solenoid ON and OFF with the scan tool.
Do you hear or feel a click as the EVAP vent solenoid is commanded ON and OFF?		 - Go to Step 7  Go to Step 10 
7  Command the EVAP pressure switching solenoid ON and OFF with the scan tool.
Do you hear or feel a click as the EVAP pressure switching solenoid is commanded ON and OFF?		 - Go to Step 14  Go to Step 12 
8
  1. Disconnect the EVAP purge solenoid.
  2. Turn ON the ignition, with the engine OFF.
  3. Connect a test lamp between the ignition positive voltage circuit of the EVAP purge solenoid and a known good ground. Refer to Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 - Go to Step 9  Go to Step 35 
9
  1. Connect a test lamp between the ignition positive voltage circuit of the EVAP purge solenoid and the control circuit of the EVAP purge solenoid. Refer to Circuit Testing in Wiring Systems.
  2. Command the EVAP purge solenoid ON with a scan tool.
Does the test lamp illuminate when the EVAP purge solenoid is commanded ON and turn OFF when the EVAP purge solenoid is commanded OFF?		 - Go to Step 27  Go to Step 24 
10
  1. Turn ON the ignition, with the engine OFF.
  2. Disconnect the EVAP vent solenoid.
  3. Connect a test lamp between the ignition positive voltage circuit of the EVAP vent solenoid and a known good ground. Refer to Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 - Go to Step 11  Go to Step 35 
11
  1. Connect a test lamp between the ignition positive voltage circuit of the EVAP vent solenoid and the control circuit of the EVAP vent solenoid. Refer to Troubleshooting with a Test Lamp in Wiring Systems.
  2. Command the EVAP vent solenoid ON, with a scan tool.
Does the test lamp illuminate when the EVAP vent solenoid is commanded ON and turn OFF when the EVAP vent solenoid is commanded OFF?		 - Go to Step 28  Go to Step 25 
12
  1. Turn ON the ignition, with the engine OFF.
  2. Disconnect the EVAP pressure switching solenoid.
  3. Connect a test lamp between the ignition positive voltage circuit of the EVAP pressure switching solenoid and a known good ground. Refer to Troubleshooting with a Test Lamp in Wiring Systems.
Does the test lamp illuminate?		 - Go to Step 13  Go to Step 35 
13
  1. Connect a test lamp between the ignition positive voltage circuit of the EVAP pressure switching solenoid and the control circuit of the EVAP pressure switching solenoid. Refer to Troubleshooting with a Test Lamp in Wiring Systems.
  2. Command the EVAP pressure switching solenoid ON, with a scan tool.
Does the test lamp illuminate when the EVAP pressure switching solenoid is commanded ON and turn OFF when the EVAP pressure switching solenoid is commanded OFF?		 - Go to Step 29  Go to Step 26 
14 
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. Connect the nitrogen/smoke supply hose of the J 41413-200  Evaporative Emission System Tester (EEST) to the EVAP service port.
  2. Turn the nitrogen/smoke valve on the control panel to SMOKE.
  3. Use the remote switch to introduce smoke into the EVAP system.
  4. Continue to introduce smoke until a steady flow of smoke is seen exiting the EVAP canister drain hose. Refer to Evaporative Emissions (EVAP) Hose Routing Diagram
  5. Plug the drain hose of the EVAP canister using the J 41413-301  plug. Refer to Evaporative Emissions (EVAP) Hose Routing Diagram .
  6. Turn the nitrogen/smoke valve on the control panel to NITROGEN.
  7. Use the remote switch to introduce Nitrogen gas into the EVAP system for 60 seconds.
  8. Inspect the entire EVAP system for exiting smoke with the J 41413-SPT  .
  9. Continue to introduce smoke, then Nitrogen, at 60 second intervals, until the source of the leak has been located.
Did you locate and repair a leak source?		 - Go to Step 44  Go to Step 15 
15 
  1. Remove the fuel fill cap.
  2. Observe the FTP sensor with the scan tool.
Is the FTP sensor near the specified value?		 0.17 mm Hg (0.09 in H2O) Go to Step 16  Go to Step 30 
16
  1. Install the fuel fill cap on the fuel fill pipe.
  2. Turn the J 41413-200  nitrogen/smoke valve on the control panel to NITROGEN.
  3. Use the J 41413-200  to pressurize the EVAP system to the first specified value.
Is the Fuel Tank Pressure Sensor parameter more than the second specified value?		 24.28 mm Hg (13 in H2O)
9.34 mm Hg (5 in H2O)		 Go to Step 17  Go to Step 19 
17 
  1. Use the remote switch to stop introducing nitrogen into the EVAP system.
  2. Disconnect the purge hose at the EVAP canister purge solenoid.
  3. Command the EVAP pressure switching solenoid ON.
Is the FTP Sensor parameter less than the specified value?		 1.86 mm Hg (1 in H2O) Go to Step 21  Go to Step 18 
18
  1. Inspect the vapor hoses on both sides of the EVAP pressure switching solenoid for a blockage or a restriction.
  2. Repair any obstruction or restriction as necessary.
Did you find and correct a condition?		 - Go to Step 44  Go to Step 41 
19 Disconnect the vapor line at the EVAP canister.
Does the J 41413-200  gage indicate the specified value?		 0 mm Hg (0 in H2O) Go to Step 36  Go to Step 20 
20 Disconnect the purge line at the EVAP canister.
Does the J 41413-200  gage indicate the specified value?		 0 mm Hg (0 in H2O) Go to Step 23  Go to Step 37 
21 
  1. Disconnect the EVAP solenoid vent hose at the EVAP canister.
  2. Command the EVAP vent solenoid ON, closed
  3. Install a hand vacuum pump to the vent hose, and apply a vacuum.
Did you achieve a vacuum?		 - Go to Step 22  Go to Step 32 
22  Command the EVAP vent solenoid OFF, open.
Does the vacuum decrease?		 - Go to Step 23  Go to Step 33 
23 
  1. Disconnect the purge hose of the EVAP canister purge solenoid at the solenoid.
  2. Connect a hand vacuum pump to the purge port of the EVAP canister purge solenoid.
  3. Apply a vacuum with the vacuum pump.
  4. You should be able to obtain and hold a vacuum.
  5. Observe the vacuum gage of the vacuum pump while commanding the EVAP purge solenoid ON, OPEN, with the scan tool.
  6. The vacuum gage should drop when the solenoid is commanded ON.
Did the purge solenoid pass both tests?		 - Go to Step 34  Go to Step 39 
24 Test the control circuit of the EVAP purge solenoid for an open, short to ground, or for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 44  Go to Step 31 
25 Test the control circuit of the EVAP vent solenoid for an open, short to ground, or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 44  Go to Step 31 
26 Test the control circuit of the EVAP pressure switching solenoid for an open, short to ground or for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 44  Go to Step 31 
27 Test for an intermittent and for a poor connection at the EVAP canister purge solenoid. 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 44  Go to Step 39 
28 Test for an intermittent and for a poor connection at the EVAP vent solenoid. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 44  Go to Step 40 
29 Test for an intermittent and for a poor connection at the EVAP pressure switching solenoid. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 44  Go to Step 41 
30 Test for an intermittent and for a poor connection at the FTP sensor. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 44  Go to Step 42 
31 Test for an intermittent and for a poor connection at the control module. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 44  Go to Step 43 
32
  1. Inspect for a leak source in the EVAP solenoid vent hose.
  2. Repair as necessary.
Did you find and correct the condition?		 - Go to Step 44  Go to Step 40 
33
  1. Inspect for a pinched or obstructed EVAP vent hose
  2. Repair as necessary.
Did you find and correct the condition?		 - Go to Step 44  Go to Step 40 
34 Inspect for a faulty EVAP canister. Refer to Evaporative Emission (EVAP) Control System Diagnosis .
Did you replace the EVAP canister?		 - Go to Step 44  Go to Step 38 
35
  1. Repair the open or short to ground in the ignition positive voltage circuit of the EVAP solenoid. Refer to Wiring Repairs in Wiring Systems.
  2. Replace the fuse as necessary.
Did you complete the repair?		 - Go to Step 44  -
36 Repair the restriction in the EVAP vapor pipe.
Did you complete the repair?		 - Go to Step 44  -
37 Repair the restriction in the EVAP purge pipe.
Did you complete the repair?		 - Go to Step 44  -
38 Was a DTC P0446 also set? - Go to DTC P0446  Go to Diagnostic Aids
39 Replace the EVAP purge solenoid. Refer to Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement .
Did you complete the replacement?		 - Go to Step 44  -
40 Replace the EVAP vent solenoid. Refer to Evaporative Emission (EVAP) Canister Vent Solenoid Valve Replacement .
Did you complete the replacement?		 - Go to Step 44  -
41 Replace the pressure switching solenoid. Refer to Evaporative Emission (EVAP) Pressure Switching Solenoid Replacement (AWD) .
Did you complete the replacement?		 - Go to Step 44  -
42 Replace the FTP sensor. Refer to Fuel Tank Pressure Sensor Replacement (FWD) or Fuel Tank Pressure Sensor Replacement (AWD) .
Did you complete the replacement?		 - Go to Step 44  -
43 Replace the control module. Refer to Powertrain Control Module (PCM) Replacement .
Did you complete the replacement?		 - Go to Step 44  -
44
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. Connect the nitrogen/smoke supply hose of the J 41413-200  Evaporative Emission System Tester (EEST) to the EVAP service port.
  2. Plug the drain hose of the EVAP canister using the J 41413-301  plug. Refer to Evaporative Emissions (EVAP) Hose Routing Diagram .
  3. Turn the nitrogen/smoke valve to NITROGEN.
  4. Pressurize the EVAP system to the specified value.
  5. Observe the J 41413-200  pressure/vacuum gage for 5 minutes.
Does the pressure/vacuum gage remain constant?		 9.34 mm Hg (5 in H2O) Go to Step 45  Go to Step 14 
45 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
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