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Home >> Volkswagen >> 2003 >> Golf (1J1) L4-2.0L (AZG) >> Repair and Diagnosis >> Powertrain Management >> Fuel Delivery and Air Induction >> Fuel Pump >> Testing and Inspection >> With Generic Scan Tool

With Generic Scan Tool



Check Fuel Pump

Recommended special tools and equipment






- 3217 ring nut wrench
- V.A.G 1318 pressure gauge
- VAG1318/11 adapter
- VAG1318/16 hose adapter
- VAG1318/17 adapter
- VAG1318/23 adapter






- VAG1332 torque wrench (40 to 200 Nm)
- VAG1348/3A remote control with VAG1348/3-2 adapter cable
- VAG1466 electrical circuit tester
- VAG1527B voltage tester
- VAG1594A connector test kit
- VAG1715 multimeter
- Measuring container
- Wiring diagram

Test requirements





- The respective fuse of Fuel Pump (FP) -G6- must be OK.
- Battery voltage must be at least 11.5 volts.
- All electrical consumers like, for example, lights and rear window heating must be switched off.
- Parking brake must be engaged or else daylight driving lights will be switched on.
- For vehicles with automatic transmission, selector lever must be in position -P- or -N-.

NOTE: Note function description of crash fuel shut-off.

Checking function and voltage supply
- Fold rear seatback forward.
- Remove cover from Fuel Pump (FP)
- Operate starter briefly. Fuel pump must audibly start up.
- Switch off ignition.

If Fuel Pump (FP) does not start up:
- Remove cover in front of fuse holder.






- Remove fuse 28 from fuse holder.
- Connect VAG1348/3A remote control to Fuel Pump (FP) and B+ at terminal 28a using VAG1348/3-2 remote control connection.
- Operate remote control.

If Fuel Pump (FP) runs:
- Check activation of Fuel Pump (FP) Relay -J17- according to wiring diagram.

If Fuel Pump (FP) does not run:






- Disconnect 4-pin harness connector from flange at fuel tank (arrow).






- Connect VAG1527 diode test lamp to the outer terminals of the connector.
- Operate remote control. LED must light up.

LED does not light up:
- Locate and repair open circuit using wiring diagram:

LED lights up (voltage supply OK):






- Use 3217 ring nut wrench to remove union nut.
- Check whether electrical wires between flange and Fuel Pump (FP) are connected.

If there are no open circuits:
- Fuel Pump (FP) faulty, replace Fuel Pump (FP), see Fuel Pump (FP), removing and installing.
- Erase DTC memory of Engine Control Module (ECM), see Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

Checking fuel delivery

Test requirements
- Voltage supply OK
- VAG1348/3A remote control connected

Test sequence
- Remove fuel filler cap from fuel filler tube.






- Disconnect supply line -3- (with white marking) and catch escaping fuel using a rag.

NOTE: Depress buttons on hose connections to do so.

CAUTION:
- The fuel or fuel lines in fuel system can become very hot (danger of scalding).
- In addition, the fuel system is under pressure. Before opening the system, place rags around the connection area and release pressure by carefully loosening the connection.
- Wear protective goggles and protective gloves when working on the fuel system.






- Connect pressure gauge (VAG1318) to fuel supply line using adapters (VAG1318/23 and VAG1318/17).
- Connect hose adapter (VAG1318/16) to adapter (VAG1318/11) of pressure gauge and hold into measuring container.
- Open shut-off valve of pressure gauge. Lever will point in direction of flow -A-.
- Operate remote control. Slowly close shut-off valve until 3 bar is indicated on pressure gauge. Do not change position of shut-off valve any more.
- Empty measuring container.
- Delivery rate of Fuel Pump (FP) is dependent on battery voltage. Therefore, connect multimeter to vehicle battery using adapter cables.
- Operate remote control 30 seconds long and measure battery voltage.






- Compare fuel quantity pumped with specified value.

*) Minimum delivery rate cubic cm/30 s
**) Voltage at fuel pump with engine off and pump running (approx. 2 volts less than battery voltage).

Read-out example:
During test, a voltage of 12.2 volts is measured at battery. Since the voltage at the pump is approx. 2 volts less than battery voltage, there is a minimum delivery rate of 200 cubic cm/30 s.

If minimum delivery rate is not obtained:
- Check fuel lines for possible restrictions (kinks) or clogging.






- Disconnect supply line -1- from fuel filter input.

NOTE: Depress buttons on hose connections to do so.

- Connect pressure gauge (VAG1318) with adapter (1318/17) to hose.
- Repeat test of delivery quantity.

If minimum delivery rate is obtained now:
- Replace fuel filter.

If minimum delivery rate is still not obtained:
- Remove Fuel Pump (FP) unit and check filter strainer for dirt.

Only if no malfunctions have been found yet:
- Fuel Pump (FP) faulty, replace Fuel Pump (FP), see Fuel Pump (FP), removing and installing.
- Erase DTC memory of Engine Control Module (ECM), see Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

Delivery rate has been obtained, but malfunctions are still suspected in the fuel supply (e.g. sporadic loss of fuel supply):
- Check Fuel Pump (FP) current draw as follows.
- Reconnect all disconnected fuel lines.






- Connect multimeter with electrical current probe to wire of 4-pin connector (terminal 1 arrow) from wiring harness.
- Start engine and let run at idle.
- Measure Fuel Pump (FP) current draw. Specified value: max: 8 amperes

NOTE: If disturbance in fuel system is sporadic, test can also be performed during a road test, but a 2nd person is required.

If current draw is exceeded:
- Fuel Pump (FP) faulty, replace Fuel Pump (FP), see Fuel Pump (FP), removing and installing.
- Erase DTC memory of Engine Control Module (ECM), see Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

Check Fuel Pump (FP) check-valve

Test requirements
- Remote control is still connected.
- Pressure gauge is still connected.

Test sequence

NOTE: This test also checks the connections of the fuel supply line from Fuel Pump (FP) unit to connection point of pressure gauge for proper seal.






- Close pressure gauge shut-off valve (lever perpendicular to direction of flow -position B-).
- Operate remote control in short intervals until a positive pressure of approx. 3 bar has built up.
- If excess pressure is built up, reduce pressure by carefully opening shut-off valve.

CAUTION: Danger of spray when opening shut-off valve. Hold container in front of open connection on pressure gauge.

- Observe pressure drop on pressure gauge. Pressure must not fall below 2.5 bar within 10 minutes.

If pressure drops further:
- Check line connections for proper seal.

If no malfunctions are found in wires:
- Fuel Pump (FP) faulty, replace Fuel Pump (FP), see Fuel Pump (FP), removing and installing.
- Erase DTC memory of Engine Control Module (ECM), see Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
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