Evaporative System Service Port: Description and Operation

EVAP SERVICE PORT




The EVAP service port is located underhood in the EVAP purge line, between the EVAP purge solenoid valve and the EVAP canister. The service port is identified by a green colored cap.

During normal EVAP system operation the EVAP canister vent valve (4) is OPEN allowing the flow of fresh air (2) into the EVAP canister. If the EVAP canister purge valve is also OPEN, the fresh air will mix with vapors stored in the canister and flow (1) from the canister to the intake manifold. The FTP sensor (7) is used to monitor system operation and the vacuum leak pump (8) provides vacuum pressure for leak detection.

The PCM performs several diagnostic tests in order to determine if the EVAP system is functioning correctly or leaking. When certain operating criteria are met before engine shutdown, the PCM will run a comprehensive series of tests when the following conditions are met:
- Five hours have elapsed after the engine was turned Off
- Altitude is less than 2,400 meters (8,000 feet)
- Battery voltage is more than 10.5 volts
- Engine coolant temperature is between 4-35°C (40-95°F)
- Intake air temperature is between 4-35°C (40-95°F)
- The ignition remains OFF for the duration of the test

The internal timer responsible for the sequencing of the EVAP system diagnostic routine is monitored by the PCM. If the PCM detects a fault in the internal timer, a DTC P2610 will set.