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Home >> Chevrolet >> 2001 >> Venture Base, Van Passenger >> Repair and Diagnosis >> External Pages >> Different car >> Section 69 (Engine Control System Self-Diagnostics - 3.4L) >> Diagnostic Tests >> DTC P0449: EVAP Canister Vent Solenoid Control Circuit >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, 2002 Chevrolet Monte Carlo, and 2002 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
  2. Turn ignition on, with engine off. With the scan tool, command the EVAP vent valve ON and OFF. Do you hear or feel a click from the EVAP vent valve when commanded ON and OFF? If yes, go to next step. If no, go to step  4.
  3. Review the Freeze Frame/Failure Records data for this DTC. Turn ignition off for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC or as close to the Freeze Frame/Failure Records data that you observe. See CONDITIONS FOR RUNNING DTC . Does this DTC fail this ignition? If yes, go to next step. If no, go to INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM.
  4. Turn ignition off. Disconnect the EVAP vent valve harness from the vent valve. Turn ignition on, with engine off. Probe the ignition voltage circuit of the EVAP vent valve at the EVAP vent valve harness connector with a test light connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step  11.
  5. Connect a test light between the control circuit and ignition voltage circuit of the EVAP vent valve at the EVAP vent valve. With a scan tool, command the EVAP vent valve ON and OFF. Does the test light turn ON or OFF with each command? If yes, go to step  9. If no, go to next step.
  6. Does the test light remain illuminated with each command? If yes, go to step  8. If no, go to next step.
  7. Test the control circuit of the EVAP vent solenoid for a short to voltage or an open. Did you find and correct the condition? If yes, go to step  14. If no, go to step  10.
  8. Test the control circuit of the EVAP vent valve for a short to ground. Did you find and correct the condition? If yes, go to step  14. If no, go to step  10.
  9. Inspect for poor connections at the harness connector of the EVAP vent valve. Did you find and correct the condition? If yes, go to step  14. If no, go to step  12.
  10. Inspect for poor connections at the harness connector of the control module. Did you find and correct the condition? If yes, go to step  14. If no, go to step  13.
  11. Repair the ignition voltage circuit of the EVAP vent valve for an open or for a short to ground. Replace the fuse if necessary. After repairs, go to step  14.
  12. Replace the EVAP vent valve. After repairs, go to step  14.
  13. Turn ignition off. Replace PCM. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After replacing PCM, go to next step.
  14. Use a scan tool in order to clear the DTCs. Turn ignition off for 30 seconds. Start the engine. Operate vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC . If yes, go to next step. If no, go to step  2.
  15. Using scan tool, observe stored information and Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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