Evaporative Emissions: Description
| CALL OUT | DESCRIPTION |
|---|---|
| 1 | Fresh Air Filter |
| 2 | Filter Hose (Filter to ESIM) |
| 3 | Evaporative System Integrity Monitor (ESIM) |
| 4 | Evaporative Canister |
| 5 | Canister Tube (Fuel Tank to Canister) |
| 6 | Purge Tube (Purge Solenoid to Canister) |
| 7 | Purge Solenoid |
| 8 | Manifold Hose (Purge Solenoid to Engine Manifold) |
| 9 | Recirculation Tube (Fuel Tank to FTPS) |
| 10 | Fuel Tank Pressure Sensor (FTPS) |
| 11 | Recirculation Tube (metal portion) (FTPS to Fuel Filler Tube) |
| 12 | Gas Cap or Cap-less Refueling Unit (if equipped) |
| 13 | Fuel Filler Tube |
| 14 | Multi-Function Control Valve (MFCV) in the Fuel Delivery Flange |
| 15 | GVV Tube (GVV to MFCV) |
| 16 | Grade Vent Valve (GVV) |
| 17 | Fuel Tank |
| 18 | Inlet Check Valve (ICV) |
| 19 | Hose - Fuel Filler Tube to ICV |
The evaporative emissions system is designed to control the release of fuel vapors into the atmosphere. The Multi-Function Control Valve (14) and Grade Vent Valve (16) are used to reduce emissions due to the venting of vapor expansion within the Fuel Tank (17). When fuel evaporates from the fuel tank, vapors pass through the Canister Tube (5) to the Evaporative Charcoal Canister (4) where they are temporarily held. When the engine is running, the vapors are drawn into the intake manifold through the Purge Tube (6). In addition, fuel vapors produced during vehicle refueling are allowed to pass through the Recirculation Tube (11) to the Evaporative Charcoal Canister (4) for temporary storage (prior to being drawn into the intake manifold). The Multi-Function Control Valve (14) and Grade Vent Valve (16) are non-serviceable components of the fuel tank assembly. The system is equipped with self-diagnosing capability using an Evaporative System Integrity Monitor (3). Refer to SWITCH, EVAPORATIVE EMISSIONS SYSTEM MONITOR, OPERATION .
The Fuel Tank Pressure Sensor (10) provides the PCM with information on vapor pressure inside the fuel tank. Excessive fuel tank pressure could cause fuel vapors to vent out the fuel filler cap or damage system components while insufficient fuel tank pressure (vacuum) caused by lack of fresh air entering the tank to take the place of consumed fuel, could lead to a collapsed tank, lines or loss of fuel pressure.
The Inlet Check Valve (18) prevents fuel from splashing back on the customer during vehicle refueling. This valve is also a non-serviceable component of the fuel tank assembly.