The Audi A6 Sedan (C8, facelift 2023) 40 TDI represents a significant iteration within the eighth generation (C8) of Audi’s executive sedan. Introduced in June 2023 and continuing through March 2025, this variant combines a 2.0-liter turbocharged diesel engine with a mild hybrid system and Audi’s quattro ultra all-wheel-drive system, paired with a seven-speed S tronic dual-clutch transmission. Positioned as a mid-range offering within the A6 lineup, the 40 TDI aimed to balance fuel efficiency, performance, and technological sophistication for the discerning buyer. It builds upon the foundation of the C8 platform (shared with the A7 Sportback) and incorporates styling and technology updates from the 2023 facelift.
Technical Specifications
| Brand | Audi |
| Model | A6 |
| Generation | A6 Sedan (C8, facelift 2023) |
| Type (Engine) | 40 TDI (204 Hp) Mild Hybrid quattro ultra S tronic |
| Start of production | June, 2023 |
| End of production | March, 2025 |
| Powertrain Architecture | MHEV (Mild Hybrid Electric Vehicle) |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Combined fuel consumption (WLTP) | 5.4-6.2 l/100 km (43.6 – 37.9 US mpg, 52.3 – 45.6 UK mpg, 18.5 – 16.1 km/l) |
| CO2 emissions (WLTP) | 141-161 g/km |
| Fuel Type | Diesel |
| Acceleration 0 – 100 km/h | 7.4 sec |
| Acceleration 0 – 62 mph | 7.4 sec |
| Acceleration 0 – 60 mph | 7 sec (Calculated) |
| Maximum speed | 246 km/h (152.86 mph) |
| Emission standard | Euro 6e |
| Weight-to-power ratio | 8.4 kg/Hp, 119.6 Hp/tonne |
| Weight-to-torque ratio | 4.3 kg/Nm, 234.6 Nm/tonne |
| Net (usable) battery capacity | 0.15 kWh |
| Battery voltage | 12 V |
| Battery technology | Lithium-ion (Li-Ion) |
| Battery location | Under the front hood |
| Recuperation output | 6 kW |
| Electric motor power | 3 Hp |
| Electric motor Torque | 60 Nm (44.25 lb.-ft.) |
| Electric motor location | Front, Longitudinal |
| Power | 204 Hp @ 3800-4200 rpm |
| Torque | 400 Nm @ 1750-3250 rpm (295.02 lb.-ft. @ 1750-3250 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | EA288evo |
| Engine displacement | 1968 cm3 (120.09 cu. in.) |
| Number of cylinders | 4 |
| Engine configuration | Inline |
| Cylinder Bore | 81 mm (3.19 in.) |
| Piston Stroke | 95.5 mm (3.76 in.) |
| Compression ratio | 15.5:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Diesel Commonrail |
| Engine aspiration | Turbocharger, Intercooler |
| Valvetrain | DOHC |
| Engine oil capacity | 5.5 l (5.81 US qt | 4.84 UK qt) |
| Coolant | 12.1 l (12.79 US qt | 10.65 UK qt) |
| Kerb Weight | 1705 kg (3758.88 lbs.) |
| Max. weight | 2325 kg (5125.75 lbs.) |
| Max load | 620 kg (1366.87 lbs.) |
| Trunk (boot) space – minimum | 530 l (18.72 cu. ft.) |
| Trunk (boot) space – maximum | 995 l (35.14 cu. ft.) |
| Fuel tank capacity | 63 l (16.64 US gal | 13.86 UK gal) |
| AdBlue tank | 12 l (3.17 US gal | 2.64 UK gal) |
| Max. roof load | 90 kg (198.42 lbs.) |
| Permitted trailer load with brakes (8%) | 2000 kg (4409.25 lbs.) |
| Permitted trailer load with brakes (12%) | 2000 kg (4409.25 lbs.) |
| Permitted trailer load without brakes | 750 kg (1653.47 lbs.) |
| Permitted towbar download | 95 kg (209.44 lbs.) |
| Length | 4939 mm (194.45 in.) |
| Width | 1886 mm (74.25 in.) |
| Width including mirrors | 2110 mm (83.07 in.) |
| Height | 1457 mm (57.36 in.) |
| Wheelbase | 2924 mm (115.12 in.) |
| Front track | 1630 mm (64.17 in.) |
| Rear (Back) track | 1617 mm (63.66 in.) |
| Front overhang | 920 mm (36.22 in.) |
| Rear overhang | 1095 mm (43.11 in.) |
| Drag coefficient (Cd) | 0.27 |
| Minimum turning circle (turning diameter) | 12.1 m (39.7 ft.) |
| Approach angle | 13.7° |
| Departure angle | 16.9° |
| Drivetrain Architecture | ICE and electric motor drive front wheels, rear drive via clutch |
| Drive wheel | All wheel drive (4×4) |
| Number of gears and type of gearbox | 7 gears, automatic transmission S tronic |
| Front suspension | Independent multi-link suspension |
| Rear suspension | Independent multi-link suspension |
| Front brakes | Ventilated discs, 318 mm |
| Rear brakes | Disc, 300 mm |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Power steering | Electric Steering |
| Tires size | 225/60 R17; 225/55 R18; 245/45 R19; 255/40 R20; 255/35 R21 |
| Wheel rims size | 7.5J x 17; 8J x 18; 8.5J x 19; 8.5J x 20; 8.5J x 21 |
INTRODUCTION
The Audi A6 Sedan (C8, facelift 2023) 40 TDI is a four-door, five-seat luxury sedan that represents a refinement of the C8 generation A6. Introduced as part of a mid-cycle refresh, this variant features a 2.0-liter turbocharged diesel engine coupled with a 48-volt mild hybrid system. This combination aims to improve fuel economy and reduce emissions while maintaining a respectable level of performance. The “40 TDI” designation signifies its power output, falling within Audi’s internal engine naming scheme. The car is built on the MLB Evo platform, and competes with other mid-size luxury sedans like the BMW 5 Series, Mercedes-Benz E-Class, and Lexus GS.
Powertrain & Engine Architecture
At the heart of the A6 40 TDI lies the EA288evo 2.0-liter inline-four diesel engine. This engine utilizes a common-rail direct injection system, delivering fuel at extremely high pressures for optimized combustion. The turbocharger, coupled with an intercooler, provides increased air intake, boosting power and torque. The engine boasts a compression ratio of 15.5:1, contributing to its efficiency. The mild hybrid system incorporates a 48-volt electric motor and a small lithium-ion battery (0.15 kWh) allowing for start-stop functionality, regenerative braking (up to 6 kW of recuperation), and a limited amount of electric assistance during acceleration. The S tronic seven-speed dual-clutch transmission provides quick and smooth gear changes. The transmission’s gear ratios are tuned for a balance of fuel efficiency and responsiveness, with a relatively tall final drive to aid highway cruising.
Driving Characteristics
The 40 TDI delivers a refined and comfortable driving experience. While not as overtly sporty as higher-powered A6 variants, the 204 hp and 400 Nm (295 lb-ft) of torque provide ample power for everyday driving and overtaking maneuvers. Acceleration from 0 to 100 km/h (0-62 mph) takes 7.4 seconds. The S tronic transmission contributes to seamless gear changes, and the quattro ultra all-wheel-drive system provides excellent traction in various weather conditions. The mild hybrid system is largely imperceptible during normal driving, but it contributes to improved fuel economy, particularly in urban environments. Compared to the more powerful 50 TDI or the petrol-powered 45 TFSI models, the 40 TDI prioritizes efficiency over outright performance.
Equipment & Trim Levels
The A6 40 TDI typically comes well-equipped as standard. Features include Audi’s Virtual Cockpit digital instrument cluster, a touchscreen infotainment system with navigation, leather upholstery, tri-zone automatic climate control, and a suite of driver-assistance systems such as lane departure warning, automatic emergency braking, and adaptive cruise control. Optional extras include a premium sound system, massaging seats, a head-up display, and various cosmetic enhancements. Interior trim levels vary, offering choices in wood, aluminum, or carbon fiber accents. The facelifted model introduced updated infotainment software and a revised dashboard layout.
Chassis & Braking
The A6 40 TDI utilizes an independent multi-link suspension setup at both the front and rear axles, providing a comfortable ride and precise handling. The suspension is tuned to balance comfort and control, offering a composed ride even on uneven surfaces. Braking duties are handled by ventilated discs at the front (318 mm) and solid discs at the rear (300 mm). The car is equipped with ABS, electronic brake-force distribution, and brake assist. The quattro ultra system intelligently distributes torque between the front and rear axles as needed, optimizing traction and stability.
Market Reception & Comparison
The A6 40 TDI was generally well-received by automotive critics. It was praised for its fuel efficiency, comfortable ride, and refined interior. However, some reviewers noted that the engine lacked the punch of the more powerful A6 variants. Compared to the 50 TDI, the 40 TDI offers lower running costs but sacrifices some performance. Against petrol-powered alternatives like the 45 TFSI, the 40 TDI provides superior fuel economy and torque, making it a more practical choice for long-distance driving. The mild hybrid system was seen as a positive step towards reducing emissions, but its impact on overall fuel economy was considered modest.
Legacy
The EA288 engine family, including the version used in the A6 40 TDI, has a reputation for reliability, although diesel particulate filter (DPF) issues can occur with frequent short trips. The S tronic transmission is generally robust, but regular servicing is crucial to ensure its longevity. As a used car, the A6 40 TDI represents a good value proposition, offering a blend of luxury, efficiency, and technology. Its relatively low running costs and comfortable ride make it a popular choice for those seeking a refined and practical executive sedan. The integration of mild hybrid technology positions it as a transitional model in Audi’s move towards greater electrification.
