P1421

3MZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P1420: Evaporative Emission Canister Small Leak

DTC P1420 - Evaporative Emission Canister Small Leak

DTC P1421 - Evaporative Emission Canister Gross Leak

DTC SUMMARY





DESCRIPTION

Refer to the EVAP system EVAP System.

MONITOR DESCRIPTION

1 P1420: EVAP (Evaporative Emission) very small leak
In operation C, the vacuum pump creates negative pressure (vacuum) in the EVAP system and the EVAP system pressure is measured. If the stabilized system pressure is higher than the second 0.02 inch leak pressure standard, the ECM (included in the HV control ECU) determines that the EVAP system has a large leakage. The ECM illuminates the MIL and sets the DTC (2 trip detection logic).
2 P1421: EVAP very gross leak
In operation C, the vacuum pump creates negative pressure (vacuum) in the EVAP system and the EVAP system pressure is measured. If the stabilized system pressure is higher than (second 0.02 inch leak pressure standard x 0.2) (near atmospheric pressure), the ECM (included in the HV control ECU) determines that the EVAP system has a large leakage. The ECM illuminates the MIL and sets the DTC (2 trip detection logic).





MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





Example of restart time





Key-off monitor sequence 1 to 15

1. Atmospheric pressure measurement





2. First reference pressure measurement





3. Vent valve stuck closed check





4. Vacuum introduction for canister





5. EVAP VSV stuck closed check





6. Second reference pressure measurement





7. Canister leak check





8. Fuel vapor-containment valve (FVCV stuck closed check)





9. Vacuum introduction for fuel tank





10. FVCV stuck closed check





11. FTP sensor stuck check





12 Third reference pressure measurement





13. Fuel tank leak check





14. FTP sensor stuck check





15. Atmospheric pressure measurement





TYPICAL MALFUNCTION THRESHOLDS

"Saturated" indicates that the EVAP pressure change is less than 0.75 mmHg (0.1 kPa) in 30 seconds.

P1421: EVAP gross leak





P1420: EVAP small leak





MONITOR RESULT

Refer to the EVAP system EVAP System.

INSPECTION PROCEDURE

Refer to the EVAP system EVAP System.