Monitor Description
Two monitors are run to confirm proper EVAP system operation. The "Key-off" monitor runs when the ignition switch is turned OFF and 5 hours have passed. The "purge flow" monitor runs when the engine is running.
- KEY-OFF MONITOR
When 5 hours have elapsed after the ignition switch is turned OFF, the electric vacuum pump creates negative pressure (vacuum) in EVAP system. Then ECM monitors for leaks and actuator malfunctions based on EVAP pressure.
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- Purge VSV stuck open
For order D, the vacuum pump creates negative pressure (vacuum) in the EVAP system. Then the pressure is measured. If the stabilized pressure is higher than "(0.02 inch leak pressure) x 0.2", the ECM determines that the purge VSV is stuck open.
- Purge VSV stuck closed
For order F, after the vacuum pump turns OFF, the pressure sensor measures the EVAP system pressure when the purge VSV has been turned ON (open). If the pressure increases 2.25 mmHg (0.3 kPa) at this time, the ECM determines that the purge VSV is operating normally. If the pressure does not increase, the ECM determines that the purge VSV is stuck closed.
- Purge VSV stuck open
- PURGE FLOW MONITOR
The purge flow monitor runs a monitor (a), and then runs another monitor (b) if necessary.
- 1st monitor
When the engine is running and the purge VSV is turned ON (open), the ECM monitors the purge flow by measuring the EVAP pressure change. If negative pressure is not created, the ECM starts the next monitor.
- 2nd monitor
The vent valve is turned ON (closed) and the EVAP system pressure is measured. If pressure change is less than 7.5 mmHg (1 kPa), the purge VSV may be stuck closed. The ECM illuminates the MIL and sets DTC 0441 (2-trip detection logic).
- 1st monitor