Monitored & Set Conditions

System is monitored with ignition off, fuel level less than 88 percent and ambient temperature 40-109°F (4-43°C). 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. DTC will set if the NVLD switch does not close within a calibrated amount of time.