Fuel Pump Control Unit: Service and Repair

Fuel Pump (FP) Control Module J538, Removing And Installing

Removing
Observe safety precautions.
Observe rules for cleanliness.

CAUTION: To lower, fuel tank must be empty for weight reasons. Drain fuel tank if necessary.

CAUTION: Observe procedures for disconnecting battery.

All except Audi RS4:







- Push cover over battery toward right - arrow 1 - and remove it upward - arrow 2 - .







- With ignition switched off, disconnect Battery Ground (GND) strap - arrow - .

Audi RS4:
- Raise luggage compartment floor covering and secure.







- With ignition switched off, disconnect Battery Ground (GND) strap - arrow - .

All:
- Open tank flap and clean area around fuel filler tube.

NOTE: Do not remove fuel cap.







- Pry tensioning ring - arrow - out from rubber gasket and press rubber gasket through toward inside.
- Remove right rear wheel.
- Remove right rear wheel housing liner.







- Unfasten bolts - 1 - for fuel filler tube.

NOTE: Ignore - 2 - .







- Remove right rear cover - 1 - on bottom of vehicle floor.

CAUTION: For weight reasons, fuel tank must be empty when lowering.







- Loosen screws - 1, 2, 3, 4, 5, 9, 10 - a maximum of 8 turns.
- Remove bolts - 6, 7, 8 - .
- Remove rear seat bench.







- Unbolt cover for right locking flange - arrows - .

Audi RS4:







- Free up electrical connector - arrow - for Fuel Pump (FP) Control Module J538 and disconnect.

All:







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







- Mark fuel return line - 1 - and fuel supply line - 2 -.

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

- Pull both lines from locking flange, by pressing release buttons.







- Remove bolts - arrows - .
- Remove Fuel Pump (FP) Control Module J538 between fuel tank and vehicle floor.

Installing
Installation is in reverse order of removal. Note the following:







- Fasten mounting straps and carrier plate - 1 through 10 - .







- Fasten fuel filler tube with Ground (GND) connection using bolt - 1 - .

CAUTION:
After installing, check electrical connection of metal ring at fuel filler tube to a blank portion of chassis using Ohm meter:
- Specification: approx. 0 ohm.

NOTE: Ignore - 2 -.

- Install right rear wheel housing liner.
- Install rear seat bench.
- Connect battery. Observe safety precautions after connecting battery.

Torque specifications
Mounting straps and carrier plate for fuel
tank to body 23 Nm
Fuel filler tube to wheel housing 23 Nm
Fuel Pump (FP) Control Module J538
to body 2.5 Nm