LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2001 >> Camaro Base, 2D Convertible, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 43 (Engine Control System Self-Diagnostics - 3.8L) >> Diagnostic Tests >> DTC P0446: EVAP Vent Valve Performance >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Pontiac Firebird and 2002 Chevrolet Camaro. However, it is still accessible from the selected car via links, so may be relevant.
  1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Did DTC P0443, P0449, P0452 or P0453 set? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go to next step.
  3. Inspect the EVAP system for the following conditions:
    • A damaged EVAP vent valve.
    • A pinched EVAP vent hose.

    Did you find and correct the condition? If yes, go to step  14. If no, go to next step.

  4. Disconnect the purge line from the EVAP purge valve. Turn ON the ignition, with the engine OFF. With a scan tool, observe the FTP parameter. Does the scan tool indicate FTP near 0 in. H2O? If yes, go to next step. If no, go to step  8.
    5. NOTE: Always zero the EVAP pressure and vacuum (in. H2O) gauges on the EVAP pressure/purge diagnostic station before proceeding with diagnosis. Do not exceed the specified value in this step. Exceeding the specified value may produce incorrect test results.
  5. Turn OFF the ignition. Reconnect all previously disconnected hardware. Install the Fuel Fill Cap Adapter (J 41415-40). Connect the EVAP Pressure/Purge Diagnostic Station (J 41413) and the vehicle fuel fill cap to the J 41415-40. Turn ON the ignition, with the engine OFF. Command the EVAP canister vent valve ON with a scan tool. With the J 41413, pressurize the EVAP system to 5 in. H2O. Rotate the EVAP pressure/purge diagnostic station rotary switch to the OFF/HOLD position. Command the EVAP canister vent valve OFF with a scan tool. Does the scan tool indicate fuel tank pressure FTP near 0 in. H2O? If yes, see DIAGNOSTIC AIDS . If no, go to next step.
  6. Disconnect the EVAP canister vent hose from the EVAP canister vent valve. Does the scan tool indicate that the fuel tank pressure is -0.5-0.5 in. H2O? If yes, go to step  10. If no, go to next step.
  7. Disconnect the EVAP vent hose from the EVAP canister. Does the scan tool indicate FTP near the second specified value? 0 in H2O If yes, go to step  13. If no, go to step  11.
  8. With a scan tool, observe the fuel tank pressure sensor voltage. Is the FTP sensor voltage more than 4.3 V? If yes, see DTC P0453: FUEL TANK PRESSURE SENSOR - HIGH VOLTAGE . If no, go to next step.
  9. Test for poor connections at the harness connector of the fuel tank pressure sensor. Did you find and correct the condition? If yes, go to step  14. If no, go to step  12.
  10. Replace the EVAP vent valve. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  14.
  11. Replace the EVAP canister. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  14.
  12. Replace the FTP sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  14.
  13. Repair for a blockage in the EVAP vent hose. After repairs, go to next step.
    14. NOTE: Do not exceed the specified value in this step. Exceeding the specified value may produce incorrect test results.
  14. Turn ON the ignition, with the engine OFF. Command the EVAP canister vent valve ON with a scan tool. Pressurize the EVAP system to 5 in. H2O with the J 41413. Place the control knob on the J 41413 to the OFF/HOLD position. Monitor the J 41413 pressure gauge. Command the EVAP canister vent valve OFF. Does the EVAP system pressure decrease? If yes, go to next step. If no, go to step  3.
  15. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
scientia non olet · About LEMON Manuals