Monitor Description
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.
| Order | Operation | Description | Time | ||
|---|---|---|---|---|---|
| - | ECM start | Power is supplied to ECM when 5 hours have passed after ignition switch is turned OFF. | - | ||
| A | Atmospheric pressure measurement | ECM turns vent valve OFF (vent) and measures EVAP system pressure to memorize atmospheric pressure. If EVAP pressure is not 525 to 825 mmHg (70 to 110 kPa), ECM cancels EVAP monitor. | 10 seconds | ||
| B | EVAP volume measurement | ECM turns vent valve ON (dosed) to close EVAP system. ECM measures EVAP pressure to check EVAP volume. If pressure is not stable, ECM interprets that EVAP volume is too large to continue EVAP monitor and cancels EVAP monitor. | 60 seconds | ||
| C | 0.02 inch leak pressure measurement | Vacuum pump creates negative pressure (vacuum) through 0.02 inch orifice and pressure is measured. ECM determines this as 0 02 inch leak pressure. | 60 seconds | ||
| D | EVAP leak check | Vacuum pump creates negative pressure (vacuum) in EVAP system and EVAP system pressure is measured. If stabilized pressure is larger than 0.02 inch leak pressure, ECM determines EVAP system has leak. If EVAP pressure does not stabilize within 12 minutes, ECM cancels EVAP monitor. | Within 12 minutes (1) | ||
| E | Check valve monitor | ECM stops vacuum pump and measures EVAP pressure increase. If there is no increase, ECM interprets this as normal. | 10 seconds | ||
| F | Purge VSV monitor | ECM opens purge VSV and measures EVAP pressure increase. If increase is large, ECM interprets this as normal. | 10 seconds | ||
| G | Final check | ECM measures atmospheric pressure and records monitor result. | - | ||
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- P043E: 0.02 inch orifice clog
For order C, the vent valve is turned OFF (vent) and the vacuum pump creates negative pressure (vacuum) through 0.02 inch orifice. Then the pressure is measured. If pressure is lower than -33.75 mmHg (-4.5 kPa) the ECM determines that 0.02 inch orifice has a clog malfunction. The ECM stops the EVAP system monitor, illuminates the MIL and sets a DTC (2-trip detection logic).
- P043F: 0.02 inch orifice high-flow
For order C, the vent valve is turned OFF (vent) and the vacuum pump creates negative pressure (vacuum) through 0.02 inch orifice. Then the pressure is measured. If pressure is higher than -7.5 mmHg (-1 kPa), the ECM determines that 0.02 inch orifice has a high-flow malfunction. The ECM stops the EVAP system monitor, illuminates the MIL and sets a DTC (2-trip detection logic).