Subaru Legacy BN/BS (2015-2019) Service Manual: Fuel system trouble in general inspection

Subaru Legacy BN/BS (2015-2019) Service Manual / Fuel injection (fuel systems)(h4do) / Fuel system trouble in general inspection

Trouble	Possible cause	Corrective action
Insufficient fuel supply to fuel injector	a. Fuel pump does not operate.
	Defective terminal contact	Inspect contact, especially ground, and tighten it securely.
	Trouble in electromagnetic or electronic circuit parts	Replace the faulty parts.
	b. Decline of fuel pump function	Replace the fuel pump.
	c. Clogged fuel filter	Replace the fuel filter. Clean or replace the fuel tank if necessary.
	d. Clogged or bent fuel line pipe, hose or tube	Clean, correct or replace the fuel line pipe, hose or tube.
	e. Air is mixed in fuel system.	Check the fuel line connections, correct or replace the defective part.
	f. Damaged diaphragm of pressure regulator	Replace the fuel filter assembly.
Leakage or blow out of fuel	a. Loose connections of fuel line pipe, hose or tube	Check the fuel line connections, correct or replace the defective part.
	b. Cracked fuel line pipe, hose or tube	Replace the fuel line pipe, hose or tube.
	c. Cracked fuel tank or defective welding part	Replace the fuel tank.
	d. Clogged or bent fuel line pipe, hose or tube	Clean, correct or replace the fuel line pipe, hose or tube.
Gasoline smell inside of compartment	a. Loose connections of fuel line pipe, hose or tube	Check the fuel line connections, correct or replace the defective part.
Gasoline smell inside of compartment	b. Defective canister	Replace the canister.
Defective fuel gauge	a. Defective operation of fuel level sensor	Replace the fuel level sensor.
Defective fuel gauge	b. Defective operation of combination meter	Replace the combination meter.
Noise	a. Large operation noise or vibration of fuel pump	Replace the fuel pump.

NOTE:

• When the vehicle is left unattended for an extended period of time, water may accumulate in the fuel tank. Fill fuel fully to prevent the problem.

• In snow-covered areas, mountainous areas, skiing areas, etc. where ambient temperatures drop to 0°C (32°F) or less throughout the winter season, use a water removing agent in the fuel system to prevent freezing fuel system and accumulating water.

• When water is accumulated in fuel filter, fill the water removing agent in the fuel tank.

• Before using water removing agent, follow the cautions noted on the bottle.

Fuel procedure

1. RELEASING OF FUEL PRESSUREWARNING:Place “NO OPEN FLAMES” signs near the working area.CAUTION:Be careful not to spill fuel.1. Remove the fuse of fuel pump from main fuse box.2. Start the ...

Throttle position sensor specification

Throttle body is a non-disassembled part, so do not remove the throttle position sensor from throttle body.Refer to “Throttle Body” for removal and installation procedure. Throttle Body > ...

Other materials:

Inspection
1. Check that the fuel pump relay has no deformation, cracks or other damages.2. Measure the resistance between fuel pump relay terminals.Terminal No.Standard1 and 21 M- or more3 and 4130.4 — 230.8 - (when 20°C (68°F))3. Connect battery positive terminal to terminal No. 3 and battery ...