Fuel Delivery, Checking

Special tools and workshop equipment required

Hand held remote control (jumper).
Multimeter.
Electrical connector test lead set.
Measuring container, fuel-resistant.

Test Conditions

Battery voltage 12.5 V
Fuel filter OK
Fuel tank at least ¹ /₄ filled.
Fuel pressure regulator OK.
Fuel Pump (FP) Control Module --J538-- OK
Ignition switched off.

Test Procedure

-- Perform a preliminary check to verify the customer's complaint. Refer to PRELIMINARY CHECK

-- Remove rear seat bench. Refer to BENCH SEAT .

Fig 1: Identifying Cover Bolts For Locking Flange

Courtesy of AUDI OF AMERICA, LLC

-- Remove bolts -arrows- and remove cover for right locking flange.

Fig 2: Disconnecting Electrical Harness Connector At Locking Flange

Courtesy of AUDI OF AMERICA, LLC

-- Disconnect the electrical connector -arrow- at locking flange.

-- Connect a hand held remote control (jumper) using an adapter cable from the connector test set to contact 5.

-- Using insulating tape, tape over second contact of the remote control (jumper) to prevent a short circuit.

-- Route switch of the remote control (jumper) forward into the engine compartment.

-- Connect alligator clip to ground (GND) point in engine compartment.

-- Connect contact 1 to battery positive terminal (B+) using a self-made jumper cable. For safety reasons, install a 10 A fuse in the wiring.

-- Remove fuel filler cap from fuel filler tube.

Fig 3: Pulling Rear Engine Cover Off

Courtesy of AUDI OF AMERICA, LLC

-- Pull rear engine cover off -arrows-.

-- Pull resonator upward and unclip it.

WARNING:

Fuel system is under pressure! Before opening system, place rags around the connection area. Then release pressure by carefully loosening the connection.

-- Disconnect fuel line -arrow-.

Fig 4: Disconnecting Fuel Line

Courtesy of AUDI OF AMERICA, LLC

-- Connect a pressure gauge adapter to the fuel line using the necessary adapters.

-- Connect assisting hose to pressure gauge and hold it in a measuring container.

-- Open shut-off valve of pressure gauge. Lever points in direction of flow.

-- Generate pressure in fuel system by pressing switch of remote control and slowly closing shut-off valve of pressure gauge.

Specification: 4 bar positive pressure.

NOTE:

From this point on do not move position of shut-off tap.

-- Empty measuring container.

-- Press switch on remote control for 15 Sec.

-- Compare quantity of fuel delivered with minimum delivery rate in diagram (cm³ /15s).

Fig 5: Delivery Rate Diagram

Courtesy of AUDI OF AMERICA, LLC

NOTE:

Voltage at fuel pump with engine stopped and pump running is approx. 2 V less than battery voltage.

If minimum delivery quantity is not obtained, the following malfunctions may be present:

Fuel lines pinched
Fuel filter clogged
Fuel pump faulty

-- Assembly is performed in the reverse of the removal.

After the repair work, the following work steps must be performed in the following sequence:

Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .