Audi A4 Wiring Diagrams. Electrical System

This page contains detailed Audi A4 wiring diagrams, covering all key components and systems of the car. The diagrams will help you quickly find faults, understand the logic of electrical equipment operation and correctly perform repairs or connections. The materials will be useful for service station specialists, auto electricians and Audi A4 owners who want to independently understand the electrical system of the car.

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Audi A4 B9: Communication Download

Audi A4 B9: Electrical system Repair Manual Download

Audi A4 B9: Wiring Diagrams Repair Manual Download

Audi A4 B9: Fitting Locations Earth points, Fuses. Relays Download

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Audi A4 B6 (8E) Schematic diagram of Bosch instrument panel connection Download

Audi А4 B6 – 2001-2005 fuse and relay Download

Audi A4 B5 (1994–2001)

frequent failures in the mass air flow (MAF) sensor;

ABS sensor failure;

problems with contacts in the ignition switch;

oxidation of the wiring under the hood;

comfort unit malfunctions (window lifters, central locking).

Audi A4 B6 (2001–2005)

failure of the crankshaft/camshaft position sensor;

malfunctions in the immobilizer;

problems with the electronic throttle assembly;

breakdowns of the coolant temperature sensor;

malfunctions of the climate control unit.

Audi A4 B7 (2004–2008)

ABS/ESP sensor failures;

malfunctions of the fuel pump and its sensors;

lambda probe errors;

failure of the airbag control unit;

faulty wiring in the trunk area (broken harnesses).

Audi A4 B8 (2008–2015)

problems with the MMI and multimedia unit;

failure of the tire pressure sensor (TPMS);

malfunctions in the steering rack module (steering angle sensor);

malfunctions of the electric parking brake drive;

failure of the oil level and temperature sensors.

Audi A4 B9 (2015–present)

errors in the Start/Stop system (battery sensor);

malfunctions in the LED optics control unit;

problems with parking sensors (PDC);

failures of the multimedia unit and virtual instrument panel;

failure of the automatic transmission control module (pressure sensor errors).