P2401

3MZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2401: Evaporative Emission System Leak Detection Pump Control Circuit Low

DTC P2401 - Evaporative Emission System Leak Detection Pump Control Circuit Low

DTC P2402 - Evaporative Emission System Leak Detection Pump Control Circuit High

DTC SUMMARY





DESCRIPTION

Refer to the EVAP system EVAP System.

MONITOR DESCRIPTION

1 P2401: Vacuum pump stuck OFF
In operation B, the vacuum pump creates negative pressure (vacuum) through the 0.02 inch orifice. The EVAP (Evaporative Emission) system pressure is then measured by the ECM (included in the HV control ECU) using the pressure sensor to determine the 0.02 inch leak pressure standard. If the pressure is higher than -1.06 kPa (-7.95 mmHg)* or lower than -4.85 kPa (-36.38 mmHg)*, the ECM interprets this as the vacuum pump being stuck OFF (not operating). The ECM then illuminates the MIL and sets the DTC (2 trip detection logic).
*: The threshold varies according to the atmospheric pressure measured in operation A. The values described above are based on an atmospheric pressure of 100 kPa (750.1 mmHg): absolute pressure.
2 P2402: Vacuum pump stuck ON
In operation B, the vacuum pump creates negative pressure (vacuum) through the 0.02 inch orifice. The EVAP (Evaporative Emission) system pressure is then measured by the ECM (included in the HV control ECU) using the pressure sensor to determine the 0.02 inch leak pressure standard. If the pressure is higher than -1.06 kPa (-7.95 mmHg)* or lower than -4.85 kPa (-36.38 mmHg)*, the ECM interprets this as the vacuum pump being stuck ON (remaining ON all the time). The ECM illuminates the MIL and sets the DTC (2 trip detection logic).
*: The threshold varies according to the atmospheric pressure measured in operation A. The values described above are based on an atmospheric pressure of 100 kPa (750.1 mmHg): absolute pressure.
HINT: The detection logic of DTCs P2401 and P2402 is the same because in both cases the 0.02 inch leak pressure standard measured in operation B is compared to the atmospheric pressure registered in operation A. The ECM calculates the difference between these pressures by deducting [the 0.02 inch leak pressure standard] from [the stored atmospheric pressure], and uses this to monitor the EVAP system pressure change.





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





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 0.1 kPa (0.75 mmHg) in 30 seconds.






MONITOR RESULT

Refer to the EVAP system EVAP System.

INSPECTION PROCEDURE

Refer to the EVAP system EVAP System.