SEAT Workshop Service and Repair Manuals

Fuel pump and fuel system: checking t  Test requirements → Anchor t  Operation and voltage supply: checking → Anchor t  Fuel flow: checking → Anchor t  Fuel pump non-return valve: checking → Anchor t  Fuel level indicator sender -G- (test procedure) → Anchor Consult the equivalence table for tools and equipment according to applicability between Seat / VW / Audi / Skoda → Chapter.

Special tools and workshop equipment required

t	Adaptor cable -SAT 1348/3-3-, see equivalent → Anchor

t	Turning tool -T20207-, see equivalent → Anchor

t	Remote control -VAG 1348/3 A-, see equivalent → Anchor

t	Voltage tester -VAG 1527B-, see equivalent → Anchor

t	Auxiliary cable kit -VAG 1594C-, see equivalent → Anchor

t	Digital multimeter -VAG 1715-, see equivalent → Anchor

t	Pressure tester -VAG 1318-, see equivalent → Anchor

t	Adaptor -VAG 1318/1-, see equivalent → Anchor

t	Adaptor -VAG 1318/11-, see equivalent → Anchor

t	Adaptor -VAG 1318/17-, see equivalent → Anchor

t	Adaptor -VAG 1318/23-, see equivalent → Anchor

t	Torque wrench kit -SAT 8010-, see equivalent → Anchor

t	Current flow diagrams, electrical fault finding and fitting locations

t  Valve -VAG 1318/9-, see equivalent → Anchor t  Step ladder Test requirements l  Battery voltage, 11.5 V minimum.

l  SC 34 fuse from the fuse holder on the left-hand side of the instrument panel, in good condition. Fuse installation → Current flow diagrams, Electrical fault finding and Fitting locations l  All electrical consumers, for example: headlights and the heated rear window must be off. l  In vehicles fitted with air conditioning/climate control, this must be disconnected. l  Ignition off.   Note Note instructions on crash fuel cut-off → Chapter. Operation and voltage supply: checking –  Move rear seat forward. –  Remove cover from fuel delivery unit under rear seat. –  Switch on ignition. The fuel pump must get started audibly for a brief space- approx. 1 second.   Note The fuel pump runs very quietly. –  Switch off ignition. If the fuel pump does not run:

–  Using the auxiliary cables in the auxiliary cable kit -VAG 1594C-, connect the remote control -VAG 1348/3A- to contact -5- on the fuel pump and to the positive on the battery (+). –  Connect contact -5- on the connection and contact -1- on the fuel pump using auxiliary cables from the auxiliary cable kit -VAG 1594C-. –  Press the remote control switch. Fuel pump runs: –  Check activation of the fuel pump relay -J17- according to electrical diagram → Current flow diagrams, Electrical fault finding and Fitting locations. Fuel pump does not run: –  Extract the 5 connections from the bracket for the fuel delivery unit.

–  Connect the voltage tester -VAG 1527B- to the exterior contacts on the connector using the auxiliary cables from the auxiliary cable kit -VAG 1594C-. –  Operate remote control. The LED should light up. If the LED does not light up: –  Use current flow diagram to locate and eliminate open circuit in wiring . → Current flow diagrams, Electrical fault finding and Fitting locations. If the diode lights (voltage supply is OK):

–  Unscrew the connecting nut using the rotation tool -T20207-. –  Check that the electrical wires between flange and fuel pump are connected. If no open circuit can be found: –  Fuel pump is defective, renew fuel delivery unit → Chapter. Fuel flow: checking Test requirements l  Voltage supply OK → Anchor l  Remote control -VAG 1348/3A- is still connected l  Fuel pressure regulator and retention pressure correct → Chapter l  Fuel filter correct. l  The fuel delivery rate is measured at 4 bar, therefore, before measuring the delivery rate it is necessary to check the fuel system pressure and the retaining pressure → Chapter. Test sequence –  Remove cover from fuse holder.

–  Remove fuse F34 for the fuel pump in the fuse holder. Fuse allocation → Current flow diagrams, Electrical fault finding and Fitting locations –  Connect remote control -VAG 1348/3A- with adapter cable -SAT 1348/3-3- to lower contact to fuel pump and battery positive (+).   Note This step is only to ensure the fuel pump is running when the engine is stopped. –  Remove filler cap from fuel tank filler neck.   Note The delivery rate of the fuel pump is measured at a pressure of 4 bar. Therefore, check fuel pressure before measuring delivery rate.   WARNING Fuel system is under pressure! Wear safety gloves and goggles to avoid injury and contact with skin. Before opening the system place a cloth around the connection. Then release pressure by carefully pulling fuel hose from connection.

–  Detach fuel return pipe -1-, pressing in the coupling keys for fuel pipes. –  Connect adapter -VAG 1318/17- to pressure tester and place adapter end in a measuring container. –  Operate the remote control -VAG 1348/3A- for 5 seconds, to fill the fuel filter. –  Empty measuring container. –  The quantity of fuel delivered by the fuel pump is dependent upon voltage. Therefore connect multimeter to the battery. –  Operate the remote control -VAG 1348/3A- for 30 seconds, and measure fuel pump voltage.

–  Compare the quantity of fuel delivered with the specification. 1)  Minimum delivery cm3/30 s 2)  Voltage on the fuel pump with the engine stopped and the pump operating (about 2 volts less than the battery voltage). Readout example: During the test, the battery voltage is measured at 12.5 volts. As the voltage at the pump is about 2 V less than the battery, this will equate to a minimum delivery of 600 cm3/30 s. If the minimum delivery rate is not attained: –  Check the fuel pipes to the filter for possible restrictions (kinks) or blockages. If the fuel line is not damaged: –  Check the flow of fuel before the filter.   WARNING Fuel supply lines are pressurised! Wear safety gloves and goggles to avoid injury and contact with skin. Before loosening hose connections, wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.

–  Pull supply hose -1- off inlet to fuel filter, press buttons on hose couplings to do this. –  Connect fuel supply pipe to pressure tester -VAG 1318-, using adaptor -VAG 1318/17-. –  Connect the adapter -VAG 1318/1- to the adapter -VAG 1318/11- of pressure gauge and place it into a measuring container. –  Open cut-off tap on pressure gauge -VAG 1318-. The lever then points in throughflow direction -A-. –  Operate the remote control -VAG 1348/3A-. Close cut-off tap slowly until pressure tester indicates 4 bar. From this point on do not move position of cut-off tap. –  Empty measuring container. –  Activate remote control again for 30 seconds. Compare the flow with the first value measured. If the minimum delivery rate is now attained: –  Replace fuel filter → Chapter. If the minimum delivery rate is again not attained: –  Remove the fuel delivery unit and check the strainer filter for soiling → Chapter. Only when up to now no fault has been detected: –  Replace fuel delivery unit → Chapter. –  Reconnect all disconnected fuel pipes. If delivery quantity has been attained, but nevertheless you suspect a fuel supply system fault (e.g. a momentary fault in the fuel supply): –  Check the current draw of the fuel pump as follows:

–  Connect the digital multimeter -VAG 1715- with the ammeter clamp to the wiring to contact 1 -arrow- of the 5-pin connector. –  Start engine and run at idling speed. –  Measure the current consumption of the fuel pump. t  Specification: 5 amps maximum   Note If there is a temporary fuel system fault, the check can also be carried out during a test drive, with the help of a second person. If the current draw is exceeded: –  Replace fuel delivery unit → Chapter. Fuel pump non-return valve: checking Test sequence

–  Using the auxiliary cables in the auxiliary cable kit -VAG 1594C-, connect the remote control -VAG 1348/3A- to contact -5- on the fuel pump and to the positive on the battery (+). –  Connect contact -5- on the connection and contact -1- on the fuel pump using auxiliary cables from the auxiliary cable kit -VAG 1594C-.   WARNING Fuel supply lines are pressurised! Wear safety gloves and goggles to avoid injury and contact with skin. Before loosening hose connections, wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.

–  Pull off supply hose -1- from fuel filter, press buttons on hose couplings to do this. –  Connect the pressure gauge -VAG 1318- to the fuel filter with the help of the adaptor -VAG 1318/17-. –  Connect adaptor -VAG 1318/11- and adaptor -VAG 1318/1-to pressure tester -VAG 1318- and place adaptor end in a measuring container. –  Close cut-off tap of pressure tester (lever at right angles to direction of flow- position -B-). –  Operate remote control at short intervals until a pressure of 4 bar has built up.   WARNING Fuel may splash when opening the shut-off valve. Wear safety goggles and appropriate clothing to avoid injury and contact with skin. Place a container under the free coupling of the pressure gauge. –  If pressure builds up too high, lower excess pressure by carefully opening the shut-off tap. –  Observe pressure drop on pressure gauge -VAG 1318-. After 10 minutes the pressure should not drop below 3 bar. If the pressure drops further: –  Check pipe connections for leaks. If no fault in lines is detected: –  Fuel pump is defective, renew fuel delivery unit → Chapter. Fuel level indicator sender -G- Test sequence –  Move rear seat forward.

–  Unclip fastening notches -arrows- and remove the protector from the fuel supply unit.

–  Disconnect the 5-pin connector terminal -1- from the fuel pump.

–  Connect the multimeter to measure resistance between the contacts -2- and -3-.

Sender fitted	Sender on the lower limit	Sender on the upper limit
Fuel gauge sender -G-	270 Ω, approximately	70 Ω, approximately

Note t  To test the resistance (values corresponding to “tank full” or “tank empty” the fuel supply unit must be removed and the sender float moved all the way to its top or bottom positions. t  If you get the value 0 Ω, a short exists; the value ∞ Ω indicates a short in the wire. t  With the fuel gauge sender -G- removed and, due to the large floater range of movement, the following values are obtained:

Sender removed	Sender on the lower limit	Sender on the upper limit
Fuel gauge sender -G-	290 Ω, approximately	60 Ω, approximately

–  Connect the multimeter to measure resistance between the contacts -3- and -4-.

Sender fitted or removed	Sender in any position
Fuel gauge sender -G-	340 Ω, approximately

Continue fitting, following the reverse order of the stripping process.