P043E
DTC P043E Evaporative Emission System Reference Orifice Clog UpDTC P043F Evaporative Emission System Reference Orifice High Flow
Malfunction Detection Conditions:
DTC SUMMARY
HINT: The 0.02 inch orifice is located inside the pump module.
DESCRIPTION
While the engine is running, if a predetermined condition (closed-loop, etc.) is met, the purge VSV is opened by the ECM and stored fuel vapors in the canister are purged to the intake manifold. The ECM changes the duty cycle ratio of the purge VSV to control purge flow volume. The purge flow volume is also determined by the intake manifold pressure. Atmospheric pressure is allowed into the canister through the vent valve to ensure that the purge flow is maintained when the negative pressure (vacuum) is applied to the canister. The following two monitors run to confirm appropriate EVAP system operation.
Key-off monitor
This monitor checks for EVAP (Evaporative Emission) system leaks and pump module malfunctions. The monitor starts 5 hours* after the ignition switch is turned OFF. More than 5 hours are required to allow enough time for the fuel to cool down to stabilize the Fuel Tank Pressure (FTP), thus making the EVAP system monitor more accurate. The electric vacuum pump creates negative pressure (vacuum) in the EVAP system and the pressure is measured. Finally, the ECM monitors for leaks from the EVAP system and malfunctions in both the pump module and purge VSV, based on the EVAP pressure.
HINT: *: If the engine coolant temperature is not below 35 degree C 5 hours after the ignition switch is turned off, the monitor check starts 2 hours later. If it is still not below 35 degree C 7 hours after the engine switch is turned off, the monitor check starts 2.5 hours later.
Purge flow monitor
The purge flow monitor consists of the two monitors. The 1st monitor is always conducted every time and the 2nd monitor is activated if necessary.
- The 1st monitor
While the engine is running and the purge VSV (Vacuum Switching Valve) is ON (open), the ECM monitors the purge flow by measuring the EVAP pressure change. If negative pressure is not created, the ECM begins the 2nd monitor.
- The 2nd monitor
The vent valve is turned ON (closed) and the EVAP pressure is then measured. If the variation in the pressure is less than 0.5 kPa (3.75 mmHg), the ECM interprets this as the purge VSV being stuck closed, and illuminates the MIL and sets DTC P0441 (2 trip detection logic).
Part 1:
Part 2:
Atmospheric pressure check: In order to ensure reliable malfunction detection, the variation between the atmospheric pressures, before and after conduction of the purge flow monitor, is measured by the ECM.
MONITOR DESCRIPTION
5 hours* after the ignition switch is turned OFF, the electric vacuum pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The ECM monitors for leaks and actuator malfunctions based on the EVAP pressure.
HINT: *: If the engine coolant temperature is not below 35 degree C (95 degree F) after 5 hours after the ignition switch is turned off, the monitor check starts 2 hours later. If it is still not below 35 degree C (95 degree F) 7 hours after the ignition switch is turned off, the monitor check starts 2.5 hours later.
1. P043E: 0.02 inch orifice clogged
In operation B, the vacuum pump creates negative pressure (vacuum) through the 0.02 inch orifice. The EVAP system pressure is then measured by the ECM, using the pressure sensor, to determine the 0.02 inch leak pressure standard. If the pressure is lower than -4.85 kPa (-36.38 mmHg)*, the ECM interprets this as a clog malfunction in the 0.02 inch orifice, and stops the EVAP (Evaporative Emission) system monitor. 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 value described above is based on an atmospheric pressure of 100 kPa (750.1 mmHg): absolute pressure.
2. P043F: 0.02 inch orifice high-flow
In operation B, the vacuum pump creates negative pressure (vacuum) through the 0.02 inch orifice. The EVAP system pressure is then measured by the ECM 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)*, the ECM interprets this as a high-flow malfunction in the 0.02 inch orifice, and stops the EVAP system monitor. 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 value described above is based on a atmospheric pressure of 100 kPa (750.1 mmHg): absolute pressure.
Monitor Strategy:
Typical Enabling Conditions (Part 1):
Typical Enabling Conditions (Part 2):
Typical Malfunction Thresholds (Part 1):
Enabling Malfunction Thresholds (Part 2):
OBD II MONITOR SPECIFICATIONS
MONITOR RESULT
Refer to Checking Monitor Status for detailed information. Mode 6 Data