Evaporative Emission Control System General

The evaporative emission control system prevents the fuel vapors that are created in the fuel tank from being released directly into the atmosphere.

The canister stores the fuel vapors that have been created in the fuel tank.

The ECM controls the purge VSV in accordance with the driving conditions in order to direct the fuel vapors into the engine, where they are burned.

In this system, the ECM checks for evaporative emission leaks and outputs DTC (Diagnostic Trouble Code) in the event of a malfunction. An evaporative emission leak check consists of an application of vacuum to the evaporative emissions system and monitoring the system for changes in pressure in order to detect a leakage.

This system consists of a purg VSV, canister, refueling valve, canister pump module, and ECM. An ORVR (Onboard Refueling Vapor Recovery) function is provided in the refueling valve. The canister pressure sensor has been included to the canister pump module. An air filter has been provided on the fresh air line. This air filter is maintenance-free. The EVAP service port has been removed.

The following are the typical conditions necessary to enable an evaporative emission leak check:

Five hours have elapsed after the engine has been turned OFF*.

Altitude: Below 2400 m (8000 feet)

Typical Enabling

Battery Voltage: 10.5 V or more


Ignition switch: OFF

Engine Coolant Temperature: 4.4 to 35"C (40 to 95"F)

Intake Air Temperature: 4.4 to 35-C (40 to 95-F)

*: If engine coolant temperature does not drop below 35"C (95"F), this time should be extended to 7 hours. Even after that, if the temperature is not less than 35"C (95"F), the time should be extended to 9.5 hours.

Service Tip-\

The canister pump module performs a fuel evaporative emission leakage check. This check is done approximately five hours after the engine is turned off. Sound may be heard coming from underneath the luggage compartment for several minutes. This does not indicate a malfunction. Pinpoint pressure test procedure is adopted by pressurizing the fresh air line that runs from the canister pump module to the air filler neck. For details, see the 2007 Camry Repair Manual (Pub. No. RM0250U).

Was this article helpful?

0 0
Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

Don't pay hundreds of dollars to find out what is wrong with your car. This book is dedicated to helping the do it yourself home and independent technician understand and use OBD-II technology to diagnose and repair their own vehicles.

Get My Free Ebook

Post a comment