Checking conditions

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Battery positive voltage (B+) supply OK
VAG1348/3A remote control connected. See FUEL PUMP, CHECKING

Remove fuel filler cap.
Disconnect fuel supply line -1- from fuel rail.
Connect VAG1318 pressure gauge with VAG1318/10 adapter to fuel supply line.

Fig 1: Connecting VAG1318 Pressure Gauge With VAG1318/10 Adapter To Fuel Supply Line
Courtesy of VOLKSWAGEN OF AMERICA, INC.
Connect VAG1318/1 hose to pressure gauge with VAG1318/11 adapter, and hold in measuring container.
Open shut-off valve on pressure gauge (lever in direction of flow).
While operating VAG1348/3A remote control, close shut-off valve slowly until gauge reads 3 bar (44 psi). Do not change position of shut-off valve.
Empty measuring container.
Operate VAG1348/3A remote control for 30 seconds.
Compare fuel quantity with specified value.

Fig 2: Graph Of Fuel Quantity Specified Values
Courtesy of VOLKSWAGEN OF AMERICA, INC.

NOTE: The following asterisk items refer to graph in Fig 2 .

* minimum fuel amount measured in cm ³ /30 sec.

** voltage at fuel pump with engine OFF and fuel pump running (approx. 2 volts less than battery positive voltage B+).

If fuel delivery quantity does not meet or exceed minimum from graph, check for the following causes:
- Fuel line kinked or obstructed
- Fuel filter obstructed
- Fuel pump malfunctioning
Replace Fuel Pump (FP) module or fuel pump.

If minimum fuel delivery is still not attained:

Pull fuel supply line -1- off inlet to fuel filter.

Fig 3: Pulling Fuel Supply Line Off Inlet To Fuel Filter
Courtesy of VOLKSWAGEN OF AMERICA, INC.
Connect VAG1318 pressure gauge to fuel line using 1318/10 adapter.
Repeat delivery check.

If minimum fuel delivery is still not attained:

Replace fuel filter.

If minimum fuel delivery is still not attained:

Remove fuel delivery unit and check filter for contamination.

If at this point no malfunction has been detected:

Replace fuel delivery unit.

If the delivery rate has been attained, but a fuel system malfunction is still suspected (for example, intermittent failure of the fuel supply system), check amperage draw of fuel pump as follows:

Reconnect all disconnected fuel lines.
Connect multimeter VAG 1715 (Fluke 83 or equivalent) to the red/yellow wire from harness connector using Fluke amperage measurement adapter.

Fig 4: Connecting Multimeter VAG 1715 To Red/Yellow Wire From Fuel Pump Harness Connector
Courtesy of VOLKSWAGEN OF AMERICA, INC.
Start engine and let idle.
Measure current draw of fuel pump.

Specification: 8 amps maximum

NOTE: If the fuel system malfunction is intermittent, you can perform the check during a test drive using a second technician.

If the amperage draw is exceeded:

Replace fuel delivery unit.