🏷️ Basic Information

Make:

Audi

Model:

A6, S6, RS6

Model Generation:

C5 (4B)

Model Year:

2004

Chassis Codes:

4B, 4B2, 4B4, 4B5, 4B6, 4BH

👋 Introduction

Market Position:

The Audi A6 (C5 generation) was positioned as a premium executive sedan and wagon, competing directly with established luxury marques like BMW's 5 Series and Mercedes-Benz E-Class. The S6 and RS6 variants offered significantly enhanced performance, targeting enthusiasts seeking high-performance luxury vehicles.

Competitive Analysis:

The 2004 Audi A6 offered a blend of sophisticated design, advanced all-wheel-drive (quattro) technology, and a comfortable, high-quality interior. Its competitors included the BMW 5 Series (E39), Mercedes-Benz E-Class (W210/W211 transition), and Lexus GS. The S6 (with its V8 engine) and the ultra-high-performance RS6 (with twin-turbo V8) were in a league of their own against more mainstream sedans, directly challenging performance variants from BMW (M5) and Mercedes-Benz (E55 AMG).

Key Features:

The C5 A6 generation is known for its distinctive 'single-frame' grille introduction, robust quattro all-wheel-drive system, and comfortable ride. The performance variants (S6/RS6) featured potent V8 engines, sport-tuned suspensions, and distinctive styling cues.

📋 Manual Details

Coverage Areas:

All Audi A6, S6, and RS6 models for the 2004 model year, encompassing all variants and body styles.

Specific Model Codes Covered:

4B (base chassis), 4B2 (Sedan), 4B4 (Allroad Quattro - potentially limited coverage), 4B5 (Avant/Wagon), 4B6 (S6 Avant), 4BH (S6 Sedan). Note: Allroad Quattro (4BH) variants might have specific sections or be more limited depending on the original manual's scope.

Page Count:

16401

Manual Type:

Factory Service and Repair Manual

Language:

English

Format:

PDF

Delivery Method:

Instant Download

Printability:

Yes

Search Ability:

Fully searchable

Compatibility:

Windows and Mac operating systems

Software Requirements:

Adobe PDF Reader and/or WinRAR

📖 Manual Coverage

Systems Covered:

General Information, Accessories & Equipment, Audio/Visual/Telematics, Brakes, Driveline & Axle, Electrical Systems, Lighting, Restraints (Airbags/Seatbelts), Steering, Suspension, Body & Frame (Interior/Exterior), Mechanical Engine (including specific variants), Transmission (Automatic and Manual), Tires & Wheels, HVAC (Heating, Ventilation, and Air Conditioning), Wiring Diagrams, and much more.

Procedures Included:

Routine maintenance, troubleshooting guides, component removal and installation, diagnostic procedures, repair instructions for all major systems, wiring harness repair, bodywork, and chassis adjustments.

Technical Depth:

Comprehensive coverage from basic fluid checks and filter replacements to advanced engine diagnostics, transmission overhaul, electrical system troubleshooting, and structural repairs. Includes detailed torque specifications, diagnostic trouble codes (DTCs), and component testing procedures.

Torque Specifications:

Extensive torque values for all critical fasteners, including engine, transmission, suspension, brakes, and body components.

Diagnostic Trouble Codes:

Listing and explanation of OBD-II diagnostic trouble codes (DTCs) relevant to the vehicle's ECUs, along with suggested diagnostic steps.

Component Identification:

Detailed diagrams and illustrations to identify the location and part numbers of various components.

Engine Mechanical:

Detailed specifications, disassembly and reassembly of all gasoline engines, including timing belt/chain systems, lubrication, cooling, fuel delivery, and emissions control components.

Transmission Repair:

Complete procedures for automatic and manual transmissions, including torque converter replacement, valve body diagnosis, clutch replacement, and gear set servicing.

Electrical Diagnostics:

Comprehensive wiring diagrams for all vehicle systems, component location guides, testing procedures for sensors, actuators, ECUs, and control modules. Includes diagnostics for comfort systems, lighting, infotainment, and powertrain electronics.

Suspension Steering Brakes:

Detailed instructions for suspension component replacement (struts, control arms, bushings), steering rack repair and replacement, brake system overhaul (pads, rotors, calipers, ABS module).

HVAC Systems:

Diagnosis and repair of climate control systems, including AC compressor, refrigerant recharging, heater core, blower motor, and control module troubleshooting.

Restraint Systems:

Detailed information on airbag system components, sensors, control modules, seatbelt pre-tensioners, and diagnostic procedures for airbag warning lights.

Body Frame Repair:

Information on interior trim removal and installation, exterior panel replacement, door and window mechanisms, and body sealant application. RS6 specific body kits and aerodynamic components may be covered.

Maintenance Procedures:

Oil and filter changes, air filter replacement, spark plug replacement, coolant flush and fill, brake fluid service, accessory belt replacement.

Diagnostic Procedures:

Troubleshooting common drivability issues, electrical faults, HVAC problems, and suspension noises using step-by-step flowcharts and diagnostic codes.

Recalibration Procedures:

Steering angle sensor calibration, throttle body relearn procedures, and ABS/ESP sensor recalibration after component replacement.

Engine Assembly Disassembly:

Step-by-step instructions for engine tear-down and reassembly, including piston and connecting rod installation, crankshaft and camshaft timing, cylinder head removal and installation, and valve adjustment.

Body Panel Alignment:

Guidance on proper alignment of doors, hood, trunk lid, and fenders to ensure correct fitment and sealing.

📊 Manual Specifications

File Format:

PDF

Print Quality:

High resolution, suitable for clear printing of text and diagrams.

Binding Type:

Not Applicable (Digital Download)

Paper Type:

Not Applicable (Digital Download)

⚙️ Engine Specifications

Primary Engine Options:

2.7L V6 Bi-Turbo (250 hp, 258 lb-ft) for RS6; 4.2L V8 (340 hp, 317 lb-ft) for S6; 2.8L V6 (201 hp, 207 lb-ft) and 3.0L V6 (220 hp, 221 lb-ft) for A6. Other A6 variants may include 1.8L Turbo I4 and 2.5L TDI Diesel engines in some markets, though the manual primarily focuses on gasoline variants and performance models commonly sold in North America.

Engine Code Examples:

2.7T (APM, BEL), 4.2 V8 (AAS, AQJ, ARU, BBD), 3.0 V6 (AVK, ASN). RS6 uses the 4.2 V8 twin-turbo (BCY).

Rs6 Performance:

Engine: 4.2L V8 Twin-Turbocharged; Horsepower: 450 PS (444 hp) @ 5700-6600 rpm; Torque: 560 Nm (413 lb-ft) @ 1950-5600 rpm; 0-60 mph: approx. 4.6 seconds.

Fuel Injection:

Multi-Point Fuel Injection (MPI) or Direct Fuel Injection (DFI) depending on specific engine variant. All models utilize Electronic Fuel Injection (EFI).

ECU System:

Bosch Motronic or similar advanced electronic engine control units.

🔧 Transmission

Standard Transmission:

5-speed Tiptronic automatic transmission (often standard on S6/RS6 and available on A6). A 6-speed manual transmission was also available on some A6 variants.

Optional Transmission:

6-speed manual transmission for certain A6 models.

Transmission Features:

Tiptronic functionality allows manual gear selection. Quattro all-wheel-drive system is integral to all transmissions.

📐 Dimensions

Sedan Dimensions Overall Length:

A6 Sedan: approx. 4814 mm (189.5 in); A6 Avant: approx. 4791 mm (188.6 in); S6/RS6: similar to A6 sedan/avant.

Wheelbase:

2803 mm (110.4 in)

Width Without Mirrors:

A6 Sedan: approx. 1775 mm (69.9 in); RS6 Sedan: approx. 1810 mm (71.3 in).

Height:

A6 Sedan: approx. 1442 mm (56.8 in); A6 Avant: approx. 1465 mm (57.7 in).

Curb Weight A6 Sedan:

approx. 1600 kg (3527 lbs)

Curb Weight Rs6 Sedan:

approx. 1820 kg (4012 lbs)

Towing Capacity:

Not typically specified for performance variants; A6 models typically have a towing capacity around 1500-2000 kg (3300-4400 lbs) depending on engine and equipment.

🛡️ Safety Features

NHTSA Front Impact Rating Driver:

Not readily available for this specific model year/trim combination from NHTSA, but generally considered good for its class.

Active Safety Features:

Anti-lock Braking System (ABS), Electronic Stability Program (ESP/ASR), Electronic Brake-force Distribution (EBD), Traction Control System (TCS).

Passive Safety Features:

Front airbags, side airbags (front and rear), front and rear head curtain airbags, active front head restraints, pre-tensioning seatbelts.

💡 Technology Features

Infotainment System:

Audi Navigation Plus system with CD player, optional Bose sound system, and DSP (Digital Signal Processing).

Driver Assistance Features:

Cruise control, parking sensors (optional on some models).

Connectivity Options:

Voice control system (optional), integrated hands-free phone system (optional).

Lighting Technology:

Xenon headlights with dynamic beam leveling (optional/standard on higher trims), LED taillights.

🔧 Maintenance

Oil Change Interval:

Typically every 5,000-7,500 miles (8,000-12,000 km) or annually, whichever comes first, depending on driving conditions. Refer to manual for specific engine type and oil specification.

Timing Belt Interval 2 7T 3 0 2 8V6:

Typically 70,000 to 90,000 miles (110,000 to 145,000 km) or 5 years. Critical to replace along with tensioners and idlers.

Engine Oil Type:

API Certified SAE 0W-40, 5W-40 or 5W-30 synthetic engine oil meeting VW 502 00 / 505 00 specifications (check manual for exact requirements for specific engine).

Coolant Type:

G12 or G12+ (red/purple) ethylene glycol-based coolant.

Transmission Fluid Automatic:

Pentosin ATF1 or equivalent synthetic ATF meeting Audi G 009 317 or G 052 162 specifications.

Transmission Fluid Manual:

G 052 172 or G 052 726 for 6-speed manual transmissions (refer to manual for specific gearbox).

Brake Fluid Type:

DOT 4

Power Steering Fluid:

Pentosin CHF 11S or equivalent.

Common Issues A6 C5:

Ignition coil failure, PCV valve issues (leading to oil leaks/consumption), power steering leaks (especially hose connections), coolant flange leaks, window regulator failures, headlight leveling sensor issues, and timing belt service on non-V8 engines (critical interval).

Common Issues S6 Rs6:

Same as A6 plus potential for turbocharger issues (RS6), intercooler leaks, and transmission cooler leaks due to higher performance demands.

Oil Filter Part Number Example:

Mann-Filter W920/3 or equivalent (verify for specific engine).

📚 Vehicle History

Brand Heritage:

Audi, part of the Volkswagen Group, has a long history of engineering excellence, particularly known for its quattro all-wheel-drive system, which revolutionized automotive traction and performance.

C5 Generation Evolution:

The C5 generation (4B) Audi A6 was produced from 1997 to 2004. The 2004 model year represents the final year of this generation, featuring refinements and updates, including the introduction of the single-frame grille on some variants, which became a signature Audi design element.

Production Location:

Primarily manufactured in Germany.

🏆 Awards & Recognition

Car And Driver 5Best Trucks:

While not directly an award for the 2004 model year, the C5 A6 platform was recognized for its overall quality and driving dynamics in various reviews of its production run. The RS6, in particular, was lauded for its supercar-like performance in a luxury sedan package.