Removal and Replacement
Fuel and EVAP System, Engine Codes BGP, BGQ, CBTA and CBUA
--> [ Fuel Tank Assembly Overview ]
--> [ EVAP/Leak Detection System Function ]
--> [ EVAP System Overview ]
--> [ EVAP System Assembly Overview ]
Fuel Tank Assembly Overview
1 Bolt, 1.5 Nm
2 Ground connection
• Ensure the connection is seated securely.
3 Vacuum line
• To the Leak detection pump (LDP).
4 Bolt, 10 Nm
5 Rivet
6 Protective plate
• Riveted to the lower clamp at factory.
• When replacing the fuel tank, set the protective plate on the filler tube and rivet clamp (holes on protective plate must coincide with holes on filler tube).
7 Wiring router
• For the Anti-lock Brake System (ABS) line.
• Clipped in on the protective plate.
8 Bolt, 25 Nm
• Always replace.
9 Fuel tank
• Removing and installing, refer to --> [ Fuel Tank ] Removal and Replacement.
10 Lock washer
11 Bracket for exhaust system
12 Securing strap
• Note installation position.
13 Heat shield
14 Supply line
• To the fuel rail.
• Ensure line is seated securely.
15 Fuel filter
• Installation position: Arrow points in direction of flow.
• Assembly overview, refer to --> [ Fuel Filter Assembly Overview ] Fuel Filter Assembly Overview.
• Removing and installing, refer to --> [ Fuel Filter ] Fuel Filter.
16 Vacuum line
• From the LDP to the intake manifold.
• Clipped in at the fuel tank.
• Ensure the line is seated securely.
17 Vent line
• From the Evaporative Emission (EVAP) canister to the EVAP canister purge regulator valve.
• Clipped in at the fuel tank.
• Ensure the line is seated securely.
18 Seal
• Always replace.
• To install, place into the opening of the fuel tank dry.
• Only lubricate the inner part with fuel when installing the fuel delivery unit.
19 Fuel delivery unit
• Removing and installing, refer to --> [ Fuel Delivery Unit ] Service and Repair.
• Checking the fuel pump, refer to --> [ Fuel Pump, Checking ] Fuel Pump, Checking
• Note installation position in the fuel tank, refer to --> [ Installed Position of the Fuel Delivery Unit ]
• With the fuel level sensor.
• Fuel level sensor removing and installing, refer to --> [ Fuel Level Sensor ] Service and Repair.
• Clean strainer if contaminated.
20 Locking ring, 110 Nm
• Ensure locking ring is seated securely.
• Use wrench (3087) to remove and install.
21 Return line
• Blue.
• Clipped to the side of the fuel tank.
• Ensure the line is seated securely.
22 Cap
• Engine codes, BGP and CBTA: Screw on.
• Engine codes, BGQ, CBUA: Bayonet connection.
• Replace gaskets if damaged.
23 Fuel filler door unit
• With rubber gasket.
24 To EVAP canister
25 Supply line
• Black
• Clipped to the side of the fuel tank.
• Ensure line is seated securely.
Installed Position of the Fuel Delivery Unit
The tab - 2 - on the fuel delivery unit must lay between the tabs - 1 - and - 3 -.
• - Arrow - points in direction of vehicle travel.
• Fuel delivery unit can only be installed in this position.
EVAP/Leak Detection System Function
Evaporative Emission (EVAP) System Function
Depending on air pressure and ambient temperature, varying quantities of fuel vapors form above the fuel surface in the fuel tank.
The EVAP system prevents these Hydro Carbon (HC) emissions from entering the atmosphere.
Fuel vapors penetrate into the EVAP canister via gravity valves integrated in the fuel tank.
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, (also called the regeneration valve) is activated by the Engine Control Module (ECM) 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 air openings of the EVAP canister. Fuel vapors temporarily stored in the active carbon and fresh air are supplied in doses to combustion via the EVAP canister purge regulator valve.
When no voltage is applied (e.g. wiring open circuit), the solenoid valve is closed. The EVAP canister is not purged.
Leak Detection Function
The EVAP system (including fuel tank) is equipped with a leak diagnostic that detects leaks (leaks) in the system.
The diagnosis operates by pressurizing the system and should detect leaks where the damage exceeds 1 mm in diameter.
During the diagnostic, the Leak Detection Pump (LDP) builds up a pressure of approximately 30 mbar in the EVAP system. The pump is switched off once the pressure is reached once. When the pressure falls to below a certain figure, the pump will switch on again. On Board Diagnostic (OBD) monitors the switch intervals and stores a Diagnostic Trouble Code (DTC) in the DTC memory if the intervals are too short.
EVAP System Overview
1 Leak Detection Pump (LDP) (V144)
• Component location: Under the wheel housing liner in the right rear wheel housing.
• Checking.
• Removing and installing, refer to --> [ Leak Detection Pump ] Service and Repair.
2 Connecting line
• From the LDP to the Evaporative Emission (EVAP) canister.
• On the EVAP canister.
3 EVAP canister
• Component location: Bottom of the spare tire well.
• Removing and installing, refer to --> [ EVAP Canister ] Service and Repair.
4 Separating point
• At the right rear on the fuel tank.
5 Throttle valve control module (J338)
Removing and installing, refer to --> [ Throttle Valve Control Module ] Service and Repair.
6 EVAP canister purge regulator valve (N80)
• Checking.
7 Vacuum line
• Connected to the intake manifold.
8 Separating point
• At the right front in the engine compartment under the coolant expansion tank.
9 Vent line
• White.
• From the EVAP canister to the EVAP canister purge regulator valve.
• Installation position: on the right side of the underbody.
• Secured to the fuel tank.
10 Vacuum line
• Green
• From the engine to the LDP.
• Installation position: on the right side of the underbody.
• Secured to the fuel tank.
11 Separating point
• At the right front on the fuel tank in the area of the fuel filter.
12 Fuel filler tube
13 Vent line
• From the filler connection to the EVAP canister.
14 Air filter housing
• For the LDP.
EVAP System Assembly Overview
1 Fuel tank
2 Vent line
• Behind the wheel housing liner.
3 Vent line
• On the vehicle floor.
4 Vent line
• To the Evaporative Emission (EVAP) canister purge regulator valve on the intake manifold.
• To remove, press the release button.
5 Bolt, 8 Nm
6 EVAP canister
• Engine codes, BGQ and CBUA.
• Component location: Bottom of the spare tire well.
• Removing and installing, refer to --> [ EVAP Canister ] Service and Repair.
7 EVAP canister
• Engine codes, BGP and CBTA.
• Component location: Bottom of the spare tire well.
• Removing and installing, refer to --> [ EVAP Canister ] Service and Repair.
8 Connecting pipe
• Pressure side.
• On the vehicle floor.
9 Connecting pipe
• Pressure side.
• Behind the wheel housing liner.
10 Bolt, 3 Nm
11 Air filter housing
• For the LDP.
12 Connecting hose
• Intake side.
13 Bracket
• For the LDP
• Secured to the right rear wheel housing liner.
14 Bolt, 2 Nm
15 Nut, 9 Nm
16 Leak Detection Pump (LDP) (V144)
• Component location: Under the wheel housing liner in the right rear wheel housing.
• Removing and installing, refer to --> [ Leak Detection Pump ] Service and Repair.
17 Connector
• Black, 3 pin.
18 Vacuum line
• From the intake manifold.