Monitored & Set Conditions
WARNING: This page is about a different car, the 2003 Dodge Dakota. However, it is still accessible from the selected car via links, so may be relevant.
The EVAP Monitors the system for a small leak with the ignition off, the fuel level less than 88 percent, ambient temperature between 39-109°F (4-43°C). DTC will set, due to temperature changes a vacuum is created in the fuel tank and EVAP system. With the EVAP system sealed, the PCM monitors the Natural Vacuum Leak Detection (NVLD) switch. If the NVLD switch does not close within a calibrated amount of time an error is detected.