battery AUDI A4 1999 B5 / 1.G AFC Engine Fuel Supply System Components Workshop Manual

20-4

CAUTION!

BEFORE disconnecting the battery:

Stop the engine.
Be sure the ignition is switched OFF (also
applies when connecting the battery). Failure
to do so may damage the Engine Control
Module (ECM).
Be sure of the proper radio code (for vehicles
equipped with coded anti-theft radio).

Be sure the battery negative (-) cable is
disconnected, when:
Working on the electrical system
Resistance (spot) welding or electric arc
welding anywhere on the vehicle.

When connecting and disconnecting
electrical test equipment (LED voltage tester,
multimeter, etc.):
Be sure the ignition is switched OFF.
Use correct adapters from the VW 1594
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20-5

Flange and fuel level sensor, removing
and installing


Observe safety measures page 20
-3

Pay attention to rules of cleanliness page 20
-2 .

WARNING!

Fire hazard. DO NOT smoke or work near
heaters or have anything in the area that can
ignite fuel!

- Switch ignition on.

- Observe fuel gauge.

CAUTION!

The fuel tank should not be more than 2/3
full. Empty fuel tank, if necessary, using an
approved fuel cart.
Determine correct radio anti-theft coding
before disconnecting the battery.

Removing
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- Disconnect battery Ground (GND) strap.

- Remove cover for fuel pump module flange
(under luggage compartment trim).

- Disconnect harness connector for fuel level
sensor and fuel pump.
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20-10

Fuel pump, testing


WARNING!

Fire hazard! DO NOT smoke or work near
heaters or have anything in area that can
ignite fuel!

Checking power supply

Battery fully charged
Fuse 28 OK
Test voltage supply to fuse 28 Repair
Manual, 2.8 Liter V-6 OBD II Fuel Injection
and Ignition, Repair Group 24

Fuel supply OK

- Switch ignition on.
Fuel pump must be heard to run briefly.
(Second person will be required for this if
surrounding noise level is too high).
If fuel pump does NOT run:

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20-11

- Supply voltage to fuel pump using VAG 1551
scan tool and "Output Diagnostic Test Mode"
function 03.

- Connect multimeter between connector terminal 1 (green wire) and
terminal 4 (brown wire) using adapter cables from VW 1594 connector
test kit.
Specified value: approx. battery positive voltage (B+)
- If specified value is obtained, reconnect harness connector.

If wiring is OK:
Checking fuel delivery - Using ohmmeter, check for continuity between connector (outside of
housing), harness connector and fuel pump.
- Replace fuel pump page 20
-7 .
- Install cover for fuel pump module.
Fuse 28 OK Relay in relay position 6 OK
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Fuel filter OK Battery fully charged
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20-12


- Disconnect fuel return line -1- at engine compartment bulkhead and
hold in measuring container.
- Connect remote control VAG 1348/3A with auxiliary cable VAG 1348/2
to fuse 28, connect positive (+) cable to battery.
- Operate remote control for 15 seconds (hold down button).

Fuel pump check valve, checking
Testing check valve Repair Manual, 2.8 Liter V-6 OBD II Fuel Injection
Ignition, Repair Group 24 - Compare quantity of fuel delivered with specified values for minimum
fuel delivery rate in graph, according to actual voltage at fuel pump.
*) - Minimum fuel delivery rate-fuel volume in cm3 (ml) delivered in15
seconds
**) - Voltage (V) at fuel pump with engine stopped, fuel pump running-
approx. 2 volts less than battery positive voltage (B+)
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