Evaporative Emission System, through 08.06
Evaporative Emission System, through 08.06
=> [ Overview ]
• Vehicles through 08.06 also have an Evaporative Emission (EVAP) canister purge solenoid valve 2 (N115) and a pressure retention valve - item 20 -.
Function
Depending on air pressure and ambient temperature, varying quantities of fuel vapors form above the fuel surface in the fuel tank.
The EVAP canister system prevents these Hydrocarbon (HC) emissions from entering the atmosphere.
Fuel vapors pass from the highest point in the tank (on the filler neck) through the reservoir and into the EVAP canister.
The activated charcoal in the canister stores these gases like a sponge.
While driving, with oxygen sensor control active (engine warm), the EVAP canister purge regulator valve 1 (N80) is activated by the Engine Control Module (ECM) (J623) in pulses dependent on load and engine speed. The opening time is dependent on input signals.
During the cleansing process (regeneration of active charcoal), the intake manifold vacuum sucks fresh air through the breather connection of the EVAP canister. The fuel vapors stored amongst the activated charcoal and fresh air are proportionately supplied to be burned.
Without electricity (for example, an open circuit) the EVAP canister purge regulator valve remains closed. The EVAP canister is not purged.
Leak Detection Function Description
The EVAP canister system (including fuel tank) is equipped with a leak diagnostic that detects leaks in the system.
The diagnostic operates by pressurizing the system and should detect leaks where the damage exceeds 0.5 mm in diameter.
During diagnosis, positive pressure is created in the EVAP system by the Leak Detection Pump (LDP) (V144). To do this, the EVAP canister purge solenoid valve 2 is closed. The pump will turn off when the pressure is attained. When the pressure falls to below a certain figure, the pump will turn on again. On Board Diagnostic (OBD) monitors the intervals and stores a Diagnostic Trouble Code (DTC) in the DTC memory if the intervals are too short.
• Hose connections are secured with either spring type or clamp type clips.
• Use hose clip pliers (VAS 6340) to install spring clips.
• or the hose clip pliers (VAS 6362) are recommended.
Observe the safety precautions. Refer to=> [ Safety Precautions ] Fuel Supply.
Observe the rules for cleanliness. Refer to => [ Clean Working Conditions ] Fuel Supply.
Overview
1 Expansion Tank
• Right side
2 Gravity Valve
3 Fuel Filler Tube
4 Bolt
• 5 Nm
5 Bracket
6 Vacuum Line
• For the leak detection pump vacuum supply.
• To the vacuum connection on the intake manifold.
• Ensure the line seated tightly
7 Leak Detection Pump (LDP) (V144)
• For checking the fuel/EVAP system for leaks, refer to => [ Fuel/EVAP System through 08.06, Checking for Leaks ] Fuel/EVAP System through 08.06, Checking for Leaks.
• Black, 3 pin connector
8 Connecting Hose
• Between the air filter housing, LDP and EVAP canister purge solenoid valve.
• Ensure the hose is securely seated.
9 Bolt
• 5 Nm
10 Air Filter Housing
• Clean if there are contaminants.
11 Rubber Bushing
• Note the installed position.
• Replace if damaged.
12 Evaporative Emission (EVAP) Canister Purge Regulator Valve 2 (N115)
• Black, 2 pin connector
13 Evaporative Emission (EVAP) Canister
• Installed location: inside the right rear wheel housing.
14 Bolt
• 9 Nm
• Quantity: 3
15 Vent Line
• To the vacuum connection on the intake manifold.
• Ensure the line is securely seated.
16 Connector
• Black, 2 pin
17 Evaporative Emission (EVAP) Canister Purge Regulator Valve 1 (N80)
• Note the installed position.
18 Rubber Bracket
• Note the installed position.
19 Vent Line
• Ensure the line is securely seated.
20 Pressure Retention Valve
• Function.
Pressure Retention Valve Function
The pressure retention valve is open in both directions from the gravity valve on the expansion tank. - Arrow 1 - is the side toward the expansion tank.
It is only open in one direction on the other side. - Arrow 2 - is the side toward the EVAP canister.