EVAP Control System Monitor

OBD System Description - EVAP Control System Monitor

System Description / Monitoring Procedure
To monitor the EVAP control system, a fuel tank pressure sensor and an EVAP canister air (vent) valve are added to the system.

EVAP System Monitoring System (ORVR):

The monitoring system measures pressure change of closed EVAP system circuit under the depressurized condition. The system also measures pressure change of closed circuit to compensate evaporative pressure with the normal range pressure, if necessary.

EVAP System Monitoring Procedure:

EVAP System Monitoring Procedure

DTC P0442 / P0455: Evaporative Emission Control System Leak Detected (Small Leak) / (Gross Leak).

Wiring Diagram:

System / Wiring Diagram

System / Circuit Description
While engine running, ECM closes EVAP canister vent valve and opens EVAP canister purge valve. If EVAP control system is in good condition, EVAP control system pressure that detected by fuel pressure sensor becomes down. After that, ECM closes EVAP canister purge valve leaving EVAP canister vent valve is closed. If EVAP emission control system is in good condition, the fuel tank pressure rises specified rate.

DTC Detecting Condition:

DTC Detecting Condition and Trouble Area

DTC Confirmation Procedure

WARNING:
- When performing a road test, select a place where there is no traffic or possibility of a traffic accident and very careful during testing to avoid occurrence of an accident.
- Road test should be carried out with 2 persons, a driver and tester, on a level road.

NOTE: Check to make sure that the following conditions are satisfied when using this DTC Confirmation Procedure.

- Engine coolant temp. at engine start: Between 10 °C and 110 °C (14 °F and 230 °F)
- Intake air temp.: Between 10 °C and 62 °C (14 °F and 144 °F)
- Altitude (barometric pressure): 2500 m, 8202 ft or less (560 mmHg, 75 kPa or more)

1. With ignition switch turned OFF, connect scan tool.
2. Turn ON ignition switch and clear DTC using scan tool.
3. Start engine and warm up to normal operating temperature.
4. Drive vehicle at 40 mph (60 km/h) or more for 12 min.
5. Keep vehicle speed at 40 mph (60 km/h) for 3 min. (Throttle valve opening is kept constant in this step.)
6. Stop vehicle and check if DTC and pending DTC exists using scan tool. If not, check if evaporative system monitoring test has completed using scan tool. If not in both of the checks (i.e., no DTC / pending DTC and evaporative system monitoring test not completed), check vehicle conditions (environmental) and repeat step 3 through 6.

Step 1 - 8:

Step 9 - 10:

DTC Troubleshooting

WARNING: This work must be performed in a well ventilated area and away from any open flames such as gas hot water.

DTC P0456: Evaporative Emission Control System Leak Detected (Very Small Leak).

Wiring Diagram:

System / Wiring Diagram

System / Circuit Description
While engine running, ECM closes EVAP canister vent valve and opens EVAP canister purge valve. If EVAP control system is in good condition, EVAP control system pressure that detected by fuel pressure and temp. sensor becomes down. After that, ECM closes EVAP canister purge valve leaving EVAP canister vent valve is closed. If EVAP emission control system is in good condition, the fuel tank pressure rises specified rate.