| DTC | Affected Circuit |
|---|---|
| P0441 | Incorrect EVAP Purge Flow |
| P0446 | EVAP Vent Control Malfunction |
DTC IDENTIFICATION
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
Circuit Description
To reduce HC emissions, evaporated fuel from fuel tank is routed through charcoal canister to the intake chamber for combustion in cylinders. ECM changes the EVAP system Vacuum Switching Valve (VSV) duty signal so the intake quantity of HC emissions is appropriate for the driving condition (engine load, engine speed, etc.) after engine is warmed up.
DTC P0441 is set if pressure in charcoal canister does not drop during purge control. DTC P0441 is also set if pressure in charcoal canister is very low compared with atmospheric pressure during purge cut-off. DTC P0446 is set if ECM does not detect continuity between vapor pressure sensor and charcoal canister while vapor pressure sensor VSV is off. DTC P0446 is also set if ECM does not detect continuity between vapor pressure sensor and fuel tank while vapor pressure sensor VSV is off. DTC P0446 is also set if pressure in charcoal canister is maintained at atmospheric pressure after purge cut-off operates. Possible causes are
- VSV for EVAP system.
- Open or shorted VSV circuit for EVAP system.
- Open or shorted VSV circuit for vapor pressure sensor.
- VSV for vapor pressure sensor.
- Open or shorted vapor pressure sensor circuit.
- Vapor pressure sensor.
- Disconnected, damaged or blocked vacuum hose.
- Charcoal canister damaged.
Note. If DTC P0441, P0446, P0450 or P0451 is output after DTC P0440, perform appropriate circuit test first before performing DTC P0440 test.