Monitor Description
5 hours*1 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:
*1: If the engine coolant temperature is not below 35°C (95°F) 5 hours after the ignition switch is turned off, the monitor check starts 2 hours later. If it is still not below 35°C (95°F) 7 hours after the ignition switch is turned off, the monitor check starts 2.5 hours later.
| Sequence | Operation | Description | Duration | ||
|---|---|---|---|---|---|
| - | ECM activation | Activated by soak timer, 5 hours (7 or 9.5 hours) after ignition switch is turned off. | - | ||
| A | Atmospheric pressure measurement | Vent valve is turned OFF (vent) and EVAP system pressure is measured by ECM in order to register atmospheric pressure If pressure in EVAP system is not between 70 kPa and 110 kPa (525 mmHg and 825 mmHg), ECM cancels EVAP system monitor | 10 seconds | ||
| B | First 0.02 inch leak pressure measurement | In order to determine 0.02 inch leak pressure standard, vacuum pump creates negative pressure (vacuum) through 0.02 inch orifice and then ECM checks if vacuum pump and vent valve operate normally. | 60 seconds | ||
| C | EVAP system pressure measurement | Vent valve is turned ON (closed) to shut EVAP system. Negative pressure (vacuum) is created in EVAP system, and then EVAP system pressure is measured Write down measured value as they will be used in leak check If EVAP pressure does not stabilize within 15 minutes, ECM cancels EVAP system monitor. |
15 minutes(1) | ||
| D | Purge VSV monitor | Purge VSV is opened and then EVAP system pressure is measured by ECM Large increase indicates normal |
10 seconds | ||
| E | Second 0.02 inch leak pressure measurement | After second 0 02 inch leak pressure measurement, leak check is performed by comparing first and second 0 02 inch leak pressure standards. If stabilized system pressure is higher than second 0.02 inch leak pressure standard, ECM determines that there is a leak in EVAP system |
60 seconds | ||
| F | Final check | Atmospheric pressure is measured and then monitoring result is recorded by ECM. | - | ||
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The vent valve turns ON (closes) and the EVAP (Evaporative Emission) system pressure is then measured by the ECM, using the pressure sensor, to conduct an EVAP leak check. If the pressure does not increase when the vent valve is open, the ECM interprets this as the vent valve being stuck open. The ECM illuminates the MIL and sets the DTC.