Diagnosis & Repair

NOTE:

If DTC P0441, P0446, P0450 or P0451 is output after DTC P0440, first trouble shoot DTC P0441, P0446, P0450 or P0451. Then, trouble shoot DTC P0440 next.
Read freeze frame data using hand-held tester or OBD II scan tool, as freeze frame data records engine conditions when malfunction is detected. When trouble shooting, it is useful for determining whether vehicle was running or stopped, engine was warmed up or not, air-fuel ratio was lean or rich, etc. at time of malfunction.

For wiring diagram, see DTC P0440: EVAP SYSTEM MALFUNCTION & DTC P0442: EVAP SYSTEM MALFUNCTION . For diagnosis and repair with hand-held tester:

For step 1, see Fig 1.
For steps 2-4, see Figure.
For steps 5-22, see Fig 2-Fig 6 .

For diagnosis and repair with OBD II scan tool, see Fig 7-Fig 11 . For vacuum or EVAP hose routing, see VACUUM DIAGRAMS article. To check ECM inputs and outputs, see PIN VOLTAGE CHARTS article. For removal and installation of components, see REMOVAL & INSTALLATION - 4-CYLINDER article. To identify circuits referenced in testing, See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. For testing of components, see SYSTEM & COMPONENT TESTING - 4-CYLINDER article.

Fig 1: DTCs P0441 & P0446 Diagnostic Procedure (Using Hand-Held Tester, Step 1)