DTC P043F: General Description
The powertrain control module (PCM) starts the evaporative emission (EVAP) system diagnosis after the vehicle has been turned to the OFF (LOCK) mode, and has met all other enable conditions (initial engine coolant temperature [ECT Sensor 1] and off for at least 5 hours). The EVAP system diagnosis is performed by reducing pressure between the EVAP canister and the atmosphere. If pressure is reduced with the fuel vapor containment valve open, the entire EVAP system will be diagnosed, and if the fuel vapor containment valve is closed, only the EVAP canister side will be diagnosed.
A malfunction is detected and a DTC is stored when changes in the pressure are equal to or more than the prescribed value after the prescribed time of starting the system pressure reduction.
EVAP leak check module operation flow
- Reference pressure measurement : Malfunction detection in the EVAP leak check module and determination of early completion of pressure reduction when normal.
- System pressure reduction : Pressure in the EVAP system is reduced to measure the ultimate pressure.
- Reference pressure re-measurement : Leak is detected by comparing with the ultimate pressure of the system pressure reduction.
- Reference value is to be measured twice considering change in the characteristics of the vacuum pump during detection.
Reference pressure is the pressure reduction caused by the reference orifice (#40 equivalent) in the EVAP leak check module used to check for leak by comparison with the system pressure reduction.