Fuel vapors are accumulated in the activated carbon canister. When the engine is running, the electronic control unit opens the valve, and fuel vapors enter the engine, where they are burned.
The control valve is used to control the fuel vapor pressure in the fuel tank.
Examination
1. Disconnect the vacuum hose from the throttle assembly and connect a vacuum pump with a vacuum hose instead.
2. According to the tables, check the following parameters on a cold engine at a coolant temperature of less than 60°C and on a hot engine at a coolant temperature of more than 80°C.
Evaporative Emission System Schematic
Cold engine
Operating mode of the engine | Underpressure | Result |
Idling | 50 kPa | Vacuum maintained |
Z000 min-1 |
Hot engine
Operating mode of the engine | Underpressure | Result |
Idling | 50 kPa | Vacuum maintained |
Within 3 minutes after increasing the speed to 3000 min-1 | Attempt to change vacuum | Vacuum maintained |
3 minutes after increasing the speed to 3000 min-1 | 50 kPa | The vacuum is maintained for a short time, after which it decreases |