Fuel Supply - 3.7l & 4.2l v8 4v (aew, Abz) Audi A8 D2

Fuel supply components, removing and installing

1. Always replace gaskets, seals and clamps during reassembly.
2. Hose connections are secured with screw- or clamp-type clamps.
3. Connecting fuel pump remote control. See «FUEL PUMP, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz__fuel-pump-checking) .
4. Relay position 10 is located on the right side of the front passenger footwell on the wheelhousing.
5. When removing and installing the fuel level sensor, make sure that the wiring is not damaged.
6. Pay attention to rules of cleanliness. See «RULES OF CLEANLINESS»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz__rules-of-cleanliness) .
7. Checking fuel pump relay: See «FUEL PUMP RELAY, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz__fuel-pump-relay-checking) .

Note. The following list refers to items in (Scheme 1).

1. Lock ring Open using special tool 3342
2. O-ring
3. Mounting tube 20 Nm (15 ft lb)
4. Banjo bolt 20 Nm (15 ft lb)
5. Fuel supply line To fuel filter
6. Lock ring Open using special tool 3217
7. Alignment marking Marking on fuel level sensor aligns with marking on fuel tank
8. Left-side fuel level sensor Removing and installing, see «FUEL LEVEL SENSORS, REMOVING AND INSTALLING»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz__fuel-level-sensors-removing-and-installing)
9. Seal
10. Fuel tank
11. Vent line
12. Banjo bolt 20 Nm (15 ft lb)
13. Fuel supply line
14. Fuel filter Note direction of flow. See «FUEL FILTER INSTALLATION POSITION»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz__fuel-filter-installation-position) .
15. Banjo bolt 20 Nm (15 ft lb)
16. Vent line
17. Vent line
18. Vent line for fuel filling
19. Fuel pump with integrated reservoir and fuel level sensor Removing and installing, see «FUEL PUMP WITH INTEGRATED RESERVOIR, REMOVING AND INSTALLING»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz)
20. Return line
21. Right-side fuel gauge sensor Removing and installing, see «FUEL LEVEL SENSORS, REMOVING AND INSTALLING»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz__fuel-level-sensors-removing-and-installing)
22. Seal
23. Compression Spring
24. Cover for fuel gauge sensor Removing and installing, see «RIGHT-SIDE FUEL LEVEL SENSOR»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz) To open turn clockwise To close turn counterclockwise

Exploded View Of Fuel Tank And Fuel Pump Components. Scheme 1

Fuel filter installation position

The fuel filter is located under the floor of the vehicle, right-rear, under the trim and in front of the rear axle.

1. Remove screws and trim.

Note. The arrow points in the direction of fuel flow to the engine.

Identifying Fuel Filter Installation Position. Scheme 2

Safety precautions when working on fuel tank

Rules of cleanliness

1. Thoroughly clean fuel system line and hose connections and the surrounding area before disconnecting.
2. Place removed components on a clean surface and cover. Use plastic sheeting or paper. Do not use fluffy rags that could leave lint!
3. Carefully cover over or seal any components that have been opened if repairs are not carried out immediately.
4. Install only clean parts: Do not remove replacement parts from the packaging until immediately before they are to be installed Do not use parts that have been stored without packaging (e.g. in toolboxes, etc.)
5. When the fuel system is opened: Avoid working with compressed air whenever possible. Avoid moving the vehicle if possible.

Functional description

The fuel tank is designed as a multi-cavity system.

The 2-stage electric fuel pump is located within the integrated fuel reservoir. The 1st stage of the electric fuel pump creates a flow of fuel that is directed to 3 suction pumps, which are in turn operated by a "jet" of fuel. Fuel surrounding each suction pump is drawn in from the different fuel tank cavities and directed to the integrated reservoir via a system of lines. The main (2nd) stage of the fuel pump draws fuel from the integrated reservoir and supplies it to the fuel injection system. The fuel pump 1st stage, the suction pump system, and the integrated reservoir together form a closed system within the fuel tank.

For reliable engine starts, the integrated reservoir must always be filled with fuel. To ensure this, even with a small refill, the fuel filler supplies fuel directly to the integrated reservoir.

Fuel level sensors, removing and installing

Note. Follow safety precautions and rules of cleanliness when working on fuel tank. See SAFETY PRECAUTIONS WHEN WORKING ON FUEL TANK and RULES OF CLEANLINESS . Before both fuel level sensors are removed, check them with a multimeter (Fluke 83 or equivalent) to see if their resistance values are in an appropriate range for the level displayed on the fuel gauge. Since the fuel level sensors are connected in series, the two resistance values must be added together when checking them against the fuel gauge reading.

Fuel tank identification

The Audi A8 is equipped with one of two fuel tanks, with fuel capacity of either 80 liters or 90 liters. Check the first digit in the production number to tell the difference between the two tanks.

The production number is stamped on the bottom right-hand portion of the fuel tank.

1. First digit "0" (e.g. D-ET 000 001) = 90 liter fuel tank
2. First digit "6" (e.g. D-ET 600 001) = 80 liter fuel tank

Scheme 3

1. Disconnect electrical connections on left- and right-side fuel level sensors.
2. Measure sensor resistance individually, then add values together and compare with specified values in table. (Scheme 3): Locating Production Number Stamped On Bottom Right-Hand Portion Of Fuel Tank

90 LITER FUEL TANK

80 LITER FUEL TANK

Left-side fuel level sensor

Removing

Scheme 4

1. Disconnect battery Ground strap.
2. Remove fuel tank sensor cover located under luggage compartment trim.
3. Disconnect fuel level sensor connector at fuel tank.
4. Use special tool 3217 to open lock ring. (Scheme 4): Using Special Tool 3217 To Open Lock Ring
5. Carefully remove fuel level sensor.

Installing

Note. The fuel level sensor must be installed so that the bracket holding the wiring for the left transfer pump is pushed down, pushing the pump to the bottom of the fuel tank. If the fuel level sensor is not installed in this way, the left cavity of the fuel tank will not completely drain and approx. 10-14 liters (2.6-3.7 gallons) of fuel will remain in the fuel tank.

Scheme 5

Scheme 6

1. Install left-side fuel level sensor. Fuel level sensor -2- must be correctly installed in bracket -1- (Scheme 5): Installing Left-Side Fuel Level Sensor In Bracket
2. Check by looking into fuel tank from side as shown (arrow). (Scheme 6): Aligning Left-Side Fuel Level Sensor In Bracket If OK
3. Press fuel level sensor into opening, and turn lock ring so that both arrows align with each other.

Scheme 7

Scheme 8

1. Remove cover for fuel level sensor and fuel pump, located on right side under luggage compartment trim. Wire and connectors may remain connected.
2. Using special tool 2012A, open cover by turning clockwise, then remove compression spring below. (Scheme 7): Opening Cover Using Special Tool 2012A
3. Using pliers, carefully lift sensor and disconnect electrical harness connector.
4. Remove fuel level sensor. (Scheme 8): Lifting Sensor And Disconnecting Electrical Harness Connector Using Plier

Note. When removing and installing the sensor, make sure that the wiring is not damaged.

Installation is the reverse of removal.

Fuel expansion tank, removing and installing

Note. See notes about servicing fuel tank, fuel system and fuel supply components. See FUEL SUPPLY COMPONENTS, REMOVING AND INSTALLING .

Note. The following list refers to items in (Scheme 9).

1. 10 Nm (7 ft lb)
2. Expansion tank
3. 10 Nm (7 ft lb)
4. Vent line From fuel tank White identification
5. Vent line From fuel tank
6. Vent line From fuel tank
7. Clamps
8. Vent line To Evaporative Emissions (EVAP) canister
9. Fuel filler
10. Connector hose
11. Clamp

Exploded View Of Fuel Expansion Tank Components. Scheme 9

Note. Follow safety precautions. See SAFETY PRECAUTIONS WHEN WORKING ON FUEL TANK .

Scheme 10

Scheme 11

Scheme 12

Scheme 13

Scheme 14

1. Disconnect battery Ground strap.
2. Remove cover for fuel pump and fuel level sensor.
3. Remove luggage compartment trim.
4. Disconnect harness connector for fuel pump and fuel level sensor. (Scheme 10): Disconnecting Fuel Supply And Fuel Return Lines At Tank
5. Relieve system pressure by carefully opening fuel supply line.
6. Disconnect fuel supply and fuel return lines. On vehicles equipped with auxiliary heater, the supply line to the fuel pump is connected to mounting tube -A-. (Scheme 10)
7. Using special tool 2012A, open fuel level sensor cover by turning clockwise, then remove compression spring below. (Scheme 11): Opening Fuel Level Sensor Cover Using Special Tool 2012A
8. Using pliers, carefully lift sensor and disconnect electrical harness connector. (Scheme 12): Lifting Sensor And Disconnecting Electrical Harness Connector
9. Remove fuel level sensor.
10. Use special tool 3342 to open fuel pump lock ring. (Scheme 13): Using Special Tool 3342 To Open Fuel Pump Lock Ring
11. Loosen mounting tube (13 mm) and leave inserted. (Scheme 14) (Scheme 14): Cut-Away View Of Fuel Pump With Integrated Reservoir Installed In Fuel Tank
12. Press firmly on mounting tube to separate fuel pump with integrated reservoir from intake housing in fuel reservoir.
13. Remove mounting tube.
14. Remove fuel pump with integrated reservoir. Pull and turn clockwise at the same time to remove pump from fuel tank.

Note. The illustration shows a cut-away view of how the fuel pump with integrated reservoir is installed in the fuel tank.

Before installing

1. Remove fuel from right cavity of fuel tank.
2. Check connection between filler tube and integrated reservoir.
3. Visually inspect integrated reservoir and connectors to transfer pump lines. Installation is in reverse order of removal.

Note. The illustration shows a cut-away view of how the fuel pump with integrated reservoir is installed in the fuel tank.

Cut-Away View Of Fuel Pump With Integrated Reservoir Installed In Fuel Tank. Scheme 15

Leak testing

1. Add approx. 3 liters (3/4 gal.) of fuel and let engine run for 10 min. Stop engine and let vehicle stand for approx. 6 hours. If the engine starts without a problem after 6 hours and runs for 10 minutes without problems, the integrated reservoir is leak-tight.

Fuel pump, checking

Test requirements

1. Fuse 1 in fuse holder -4- (right side A-pillar) OK
2. Fuel pump relay (passenger side footwell, position 6) OK
3. Fuel filter in good condition
4. Battery fully charged (12 V min.)

Scheme 16

Scheme 17

1. Disconnect fuel pump relay from relay panel (position 6). (Scheme 16): Locating Fuel Pump Relay In Relay Panel (Position 6)
2. Connect lead of adapter cable into socket 52. (Scheme 17): Connecting Lead Of Adapter Cable Into Socket 52
3. Connect clip from remote control to terminal 30, located under relay position 1.

Note. The fuel pump relay is located on the relay panel in the passenger-side footwell. The fuse panel is located on the right-side A-pillar-fuse 1 in fuse holder 4.

Checking

1. Connect remote control. See «FUEL PUMP, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz__fuel-pump-checking).
2. Remove cover under luggage compartment trim at left rear.
3. Disconnect fuel pump and level sensor harness connector.
4. Press and hold remote control switch, and check for voltage between connector terminals 1 (green) and 4 (brown). (Scheme 18) Specified value: approx. battery voltage

Checking For Voltage Between Connector Terminals 1 (Green) And 4 (Brown). Scheme 18

If voltage is OK

1. Reconnect harness connector, actuate remote control, and make sure fuel pump runs.

If fuel pump does not run

1. Remove fuel pump ( «FUEL PUMP WITH INTEGRATED RESERVOIR, REMOVING AND INSTALLING»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz) ) and check for continuity between harness connector, connector on housing, and fuel pump. Specified value: 0 ohm (continuity)

Checking For Continuity Between Harness Connector, Connector On Housing, And Fuel Pump. Scheme 19

If there is no continuity

1. Repair or replace wiring.

If wiring is OK (and fuel pump does not run)

1. Replace fuel pump.

Fuel pump delivery rate, checking

1. Fuse 1 in fuse holder -4- (right side A-pillar) OK. See «FUEL PUMP, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz__fuel-pump-checking) .
2. Fuel pump relay (passenger side footwell, position 6) OK
3. Fuel filter in good condition
4. At least 12 volts at fuel pump (when pump is running)

Scheme 20

1. Connect remote control. See «FUEL PUMP, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz__fuel-pump-checking).
2. Remove return line at fuel pressure regulator.
3. Attach auxiliary hose, Part No. 8A0 201 351, to fuel pressure regulator and hold opposite end in measuring beaker. (Scheme 20): Attaching Auxiliary Hose To Fuel Pressure Regulator
4. Actuate remote control to operate fuel pump continuously for 15 seconds.
5. Compare fuel delivery rate to specified values in «FUEL DELIVERY RATE SPECIFICATIONS»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz) table.

FUEL DELIVERY RATE SPECIFICATIONS

Note. After each test, approx. 3 liters (3/4 gal.) of fuel must be added to the fuel tank through the fuel filler.

Fuel pump check valve, checking

1. Fuel pressure regulator OK
2. Fuel pump and fuel injectors OK
3. No leaks in fuel lines

Scheme 21

Scheme 22

1. Disconnect fuel supply line at fuel rail. (Scheme 21): Disconnecting Fuel Supply Line At Fuel Rail
2. Install pressure gauge VAG 1318 with adapter between fuel supply line and fuel rail. (Scheme 22): Installing Pressure Gauge VAG 1318 With Adapter Between Fuel Supply Line And Fuel Rail
3. Connect remote control VAG 1348/3A. See «FUEL PUMP, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz__fuel-pump-checking).
4. Press and hold remote control switch for approx. 30 seconds.
5. Close valve on pressure gauge.
6. Observe drop in pressure for 10 minutes. Maximum pressure drop (after 10 minutes): 0.5 bar (7 psi)

If pressure drop is not OK

1. Check pressure gauge connectors for leaks.
2. Check fuel lines for leaks.

If there are no leaks

1. Replace fuel pump and integrated reservoir. See «FUEL PUMP WITH INTEGRATED RESERVOIR, REMOVING AND INSTALLING»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz) .

Troubleshooting Chart - Engine Does Not Start & Engine Starts, But Stalls. Scheme 23

1. To check fuel level sensor resistance, see «FUEL LEVEL SENSORS, REMOVING AND INSTALLING»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz__fuel-level-sensors-removing-and-installing) .
2. To replace fuel pump, see «FUEL PUMP WITH INTEGRATED RESERVOIR, REMOVING AND INSTALLING»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz) .
3. To connect remote control, see «FUEL PUMP, CHECKING»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz__fuel-pump-checking) .
4. To replace seals for intergrated reservoir, see «FUEL PUMP WITH INTEGRATED RESERVOIR, REMOVING AND INSTALLING»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz) .

TROUBLESHOOTING: ENGINE STOPS RUNNING WHILE DRIVING

Fuel tank, removing and installing

1. Fuel tank empty

1. Remove rear sub-frame: See «REAR SUBFRAME (AWD)»(/audi/a8/d2-1994-1999/remont/suspension-rear/#suspension-rear__rear-subframe-awd) .

Scheme 24

Scheme 25

Scheme 26

Scheme 27

Scheme 28

Scheme 29

1. Remove cover for fuel level sensor and fuel pump, located under trim in luggage compartment.
2. Disconnect electrical connectors on left and right sides, secure wiring harness and connectors out of the way.
3. Remove fuel level sensor. See «FUEL LEVEL SENSORS, REMOVING AND INSTALLING»(/audi/a8/d2-1994-1999/remont/fuel-system/#fuel-supply-37l-42l-v8-4v-aew-abz__fuel-level-sensors-removing-and-installing).
4. Remove screws and cover below floor panel on left side. (Scheme 24): Removing Screws And Cover Below Floor Panel On Left Side
5. Remove screws and cover below floor panel on right side. (Scheme 25): Removing Screws And Cover Below Floor Panel On Right Side
6. Disconnect fuel supply line -1- and return line -2- at fuel filter. (Scheme 26): Disconnecting Fuel Supply Line -1- And Return Line -2- At Fuel Filter
7. Loosen both fuel filler connecting hoses (arrows) between expansion tank and fuel tank. (Scheme 27): Loosening Both Fuel Filler Connecting Hoses Between Expansion Tank And Fuel Tank
8. Slide hose from expansion tank end onto fuel filler tube -1-. Detach fuel filler tube from fuel tank and remove through opening in chassis member. Connecting hose must remain on fuel tank.
9. Cut open tie wrap -2-.
10. Loosen clamps -3- and disconnect vent lines. (Scheme 27)
11. Remove bracket for parking brake cable from tank retaining straps on right side. (Scheme 28): Removing Bracket For Parking Brake Cable From Tank Retaining Straps On Right Side
12. Remove rear tank retaining strap -1-. (Scheme 29)
13. Loosen two front retaining straps -2-. (Scheme 29): Removing Tank Retaining Straps
14. Support fuel tank using transmission hoist VAG 1383 with VAG 1359/2, and remove middle tank retaining straps -3-.
15. Lower fuel tank and guide vent lines through opening in chassis member. (Second technician required). Vent lines must not be bent.
16. Remove fuel tank.

Installation is the reverse of removal.

Tank retaining strap tightening torque: 20 Nm (15 ft lb)

Note. Notes on installation: When installing the fuel tank, make sure that the wires for the ABS wheel speed sensors are correctly routed. First slide the ventilation lines through the opening on the side chassis member and then guide in the fuel tank.

Evaporative Emissions (EVAP) control system, servicing

Note. The EVAP canister is located in the left-rear wheelhousing behind the wheelhousing liner. When working on the EVAP canister the wheelhousing liner should be removed.

Note. The following list refers to items in see scheme 30.

1. From expansion tank 6 mm diameter
2. To engine 8 mm diameter
3. Vent line Line ends at vehicle floor
4. Evaporative Emissions (EVAP) canister
5. EVAP canister purge regulator valve Checking operation: See «EVAPORATIVE EMISSIONS (EVAP) CANISTER PURGE REGULATOR VALVE, ELECTRICAL TESTING»(/audi/a8/d2-1994-1999/remont/fuel-system/#multiport-fuel-injection-mfi-37l-42l-v8-4v-aew-abz) .
6. To connection between intake manifold and throttle body

Description

The leak detection threshold has recently changed from 1.0 mm (0.040 in.) to 0.5 mm (0.020 in.). These changes to EPA regulations regarding EVAP system integrity indicated that additional resources for more accurate EVAP system diagnosis are necessary.

The KLI9210 EVAP Tester allows testing using nitrogen to pressurize the EVAP system and a smoke generator or ultrasonic tester to locate the source of EVAP system concerns.

The following procedure will outline general use of the KLI9210 EVAP Tester. It is intended as a guideline, as EVAP systems vary between models.

Test EVAP system using Leak Detection Pump (LDP) - V144- (m.y. 1998 and later)

For vehicles without LDP, proceed to "Perform EVAP tester self-test".

For vehicles with LDP

1. Perform leak test using VAS 5051 Scan Tool and Basic Setting mode.

If vehicle fails above test ("System not OK")

1. Verify fuel cap is properly closed; repeat test.

If "System OK" after re-test

1. Erase DTC memory (if necessary).
2. Repeat test several times to ensure proper EVAP system operation (remove and re-install fuel cap before each test).
3. Perform quality check and return vehicle to customer.

Note. If the vehicle passes the above EVAP system, test, DTCs may be sporadic; the entire EVAP system should be carefully inspected.

If VAS 5051 continues to indicate "System not OK" after re-test, proceed to next step.

Perform EVAP tester self-test

Note. Always perform system self-test of KLI9210 EVAP Tester prior to use to ensure that there are no leaks. Refer to KLI9210 instruction manual for specific instructions.

1. Connect vehicle interface hose to self-test port -1-, ensuring that fitting is finger-tight. Over-tightening will damage fitting.
2. Turn control valve -2- to "Test". Gauge -3- should read 14 + 1 in. of water.

If gauge does not read 14 + 1 in. of water

Connecting Vehicle Interface Hose To Self-Test Port -1-, Ensuring Fitting Is Finger-Tight. Scheme 30

1. Verify that valve on EVAP tester nitrogen cylinder is open and that cylinder has sufficient pressure before continuing.
2. Turn fine adjust regulator knob (arrow) until gauge reads 14 in. of water; tighten lock nut. (Scheme 31): Turning Fine Adjust Regulator Knob Until Gauge Reads 14 in. Of Water

Note. If gauge still does not read within above range, contact K-Line Customer Service - Technical Support for additional instructions before continuing.

1. Check flow meter -4-. (upper illustration). Meter must indicate no flow.
2. Turn control valve to "Hold" position.
3. Check gauge. Gauge must hold pressure

If gauge leaks down

1. Verify that vehicle interface hose is firmly seated and repeat previous six steps before continuing.

If gauge continues to leak down

1. Use ultrasonic tester (described later) to locate and repair leak before continuing.

Note. If the leak cannot be located or repaired, contact K-Line Customer Service - Technical Support.

Calibrate KLI9210 Tester

Determine vehicle leak threshold

To m.y. 2000: leak threshold 0.040 in.

From m.y. 2001: leak threshold 0.020 in.

Scheme 31

1. Attach test hose to appropriate preset port (black arrows). (Scheme 32): Attaching Test Hose To Appropriate Preset Port
2. Turn control valve from "Hold" to "Test".
3. Set flow meter flag (white arrow) at indicated value on flow meter.
4. Turn control valve to "Hold"; remove test hose.

Scheme 32

1. Connect fuel cap tester to hose.
2. Screw fuel cap tightly to cap receiver (arrow).
3. Turn control valve to "Test". (Scheme 33): Screwing Fuel Cap Tightly To Cap Receiver
4. Read flow meter on tester.

If no flow is indicated

1. Proceed to "Test LDP for internal leaks".

If flow is indicated

1. Replace fuel cap and re-test.

If new fuel cap shows no flow

1. Repeat Leak Test, with new fuel cap installed, using VAS 5051 and Basic Settings mode.

If Leak Test shows "System OK"

1. Perform quality check and return vehicle to customer.

Test LDP -V144- for internal leaks

If vehicle is not LDP-equipped, proceed to "Test EVAP system".

1. Clamp off LDP outlet (EVAP side) using Special Tool No. 3094 or equivalent.

1. Repeat Leak Test using VAS 5051 and Basic Setting mode. VAS 5051 should immediately indicate "System OK"
2. Repeat test several times to verify result. If test continues to indicate "System OK", remove clamp and proceed to "Test EVAP System".

If VAS 5051 indicates "System not OK"

1. Replace LDP and repeat test.

If VAS 5051 indicates "System OK" after LDP is replaced and test result is verified

1. Perform quality check and return vehicle to customer.

Test EVAP System

If vehicle is not LDP-equipped

1. Plug or clamp EVAP canister outlet and proceed to step "Continued for all vehicles" (below).

If vehicle is LDP-equipped

Scheme 33

1. Plug or clamp LDP inlet (filter side) using Special Tool No. 3094 or equivalent.
2. Attach fuel cap adapter to filler neck (arrow) and test hose to adapter. (Scheme 34): Attaching Fuel Cap Adapter To Filler Neck And Test Hose To Adapter
3. Turn control valve from "Hold" to "Test".
4. Allow fuel system to pressurize.

Note. Fuel system pressurization depends on volume of fuel system and amount of fuel in tank.

If fuel system pressurization does not stabilize

1. Verify all fuel system outlets have been sealed before continuing.

Note. Any flow shown on flow meter indicates a leak. Flow before flow meter flag set at vehicle leak standard may indicate a sporadic DTC.

If flow meter on tester registers flow near or above preset pressure

Scheme 34

1. Clamp off hose (arrow) leading from EVAP purge regulator valve -N80- to intake manifold (pictured: AHA engine in A6). see scheme 36: Clamping Off Hose Leading From EVAP Purge Regulator Valve -N80- To Intake Manifold

If flow stops

1. Replace EVAP purge regulator valve -N80- and repeat test before continuing.

If meter indicates no flow after test

1. Perform a quality check and return vehicle to customer.

If flow continues, proceed as follows

Method 1: Locate leak with smoke generator

1. Connect leads from smoke generator to vehicle battery.
2. Use smoke generator trigger to charge fuel system with smoke.
3. Inspect complete EVAP system for escaping smoke.

Method 2: Locate leak with ultrasonic tester

General search: tester only

Localized search: tester with extension (on left in illustration)

If leak cannot be located

1. Disconnect and plug or clamp shut EVAP lines to isolate fuel tank, using Special Tool No. 3094 or equivalent, before continuing.

Identifying Ultrasonic Tester. Scheme 35

If flow stops

1. Reconnect EVAP lines to search area that was isolated

If leak or source of fuel odor cannot be found

1. Contact Audi Dealer Technician Helpline.

When leak has been located

1. Repair leak and repeat EVAP system test.
2. Perform quality check and return vehicle to customer.

Note. Because leak may be at top of fuel tank, it may not be possible to locate through fuel pump/sending unit access plate. Fuel tank may need to be lowered to locate the leak.

Accelerator pedal cable, adjusting

1. Cable attached at pedal and throttle body
2. Cable sleeve not secured by locking clip

1. Insert spacer between accelerator pedal and stop bolt, and attach with electrical tape. Dimension -a- = 15 mm (19/32 in.) see scheme 38: Measuring Thickness -a- Of Spacer
2. Depress accelerator pedal to wide open throttle position.
3. Pull back accelerator pedal cable sleeve until lever on throttle body is resting against wide open throttle stop. Insert locking clip between thrust plate and cable sleeve.
4. Remove spacer at throttle pedal.
5. Check kick down switch: See «MEASURING VALUE BLOCK, READING (FUNCTION 08)»(/audi/a8/d2-1994-1999/remont/automatic-trans/#on-board-diagnostic-obd-5-spd-automatic-transmission-01v-fwd__measuring-value-block-reading-function-08) (01V, FWD vehicles) or «READ MEASURING VALUE BLOCK (FUNCTION 08)»(/audi/a8/d2-1994-1999/remont/automatic-trans/#on-board-diagnostic-obd-5-spd-automatic-transmission-01l-awd__read-measuring-value-block-function-08) (01L, AWD vehicles).

See also:
• FUEL PUMP RELAY, CHECKING
• REAR SUBFRAME (AWD)
• EVAPORATIVE EMISSIONS (EVAP) CANISTER PURGE REGULATOR VALVE, ELECTRICAL TESTING
• MEASURING VALUE BLOCK, READING (FUNCTION 08)
• READ MEASURING VALUE BLOCK (FUNCTION 08)
• SAFETY PRECAUTIONS WHEN WORKING ON FUEL TANK
• FUEL PUMP, CHECKING
• RULES OF CLEANLINESS
• FUEL LEVEL SENSORS, REMOVING AND INSTALLING
• FUEL FILTER INSTALLATION POSITION
• FUEL PUMP WITH INTEGRATED RESERVOIR, REMOVING AND INSTALLING
• FUEL SUPPLY COMPONENTS, REMOVING AND INSTALLING