Audi A4 review – MPG, running costs & CO2 (2015-2024)

​Audi has gone to great lengths to improve the Audi A4's fuel-efficiency figures. It's not as if the old car's CO2 emissions and fuel economy were bad in comparison to rivals – far from it – but Audi has to keep cars like the refreshed BMW 3 Series and Mercedes C-Class at bay in order for the A4 to remain competitive.

Company-car drivers are likely to be unimpressed that there's no plug-in hybrid version of the A4, which is a strange omission. There are some strong rivals here, including the BMW 330e and Mercedes C 300 e that offer low BiK bands thanks to their low CO2 emissions. 

Audi A4 MPG & CO2

Like many compact executive cars, the Audi A4 has a range of engines to choose from and mild-hybrid technology has been rolled out to boost fuel-efficiency and help cut CO2 emissions. It works by capturing energy while the car is slowing down and using it to power the car's electrical systems.

The most economical engine in the range was the 2.0-litre diesel; the 134bhp ‘30 TDI’ that’s able to return up to 60.1mpg, but this is no longer available to order new. That’s not the end of the world, as even the 161bhp ‘35 TDI’ is capable of up to 58.9mpg in trims with smaller wheels. The A4 now has a reduced engine range to choose from, but all are relatively frugal. The more economical diesels are best for high-mileage drivers, but relatively high BiK bands mean the petrol models are often now more appealing for company-car drivers.

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A more powerful, 201bhp version of the 2.0-litre diesel engine is also available with standard quattro all-wheel drive. Badged 40 TDI, it promises fuel economy of up to 53.3mpg. Other engine highlights include a 2.0-litre 35 TFSI petrol with 148bhp, which is capable of up to 45.6mpg and is the least expensive engine in the range to buy.

There are further petrol choices, as you can order an A4 with 201bhp, while a range-topping 261bhp version has now been discontinued. While the 40 TFSI is very smooth, it’s best for low-mileage drivers as fuel economy of up to 44.8mpg is only average.

After the first year's CO2-based VED road tax (generally included in the on-the-road price), all Audi A4s cost the standard rate each year to tax. Those with a list price (including options) of more than £40,000 are liable for an additional luxury car surcharge in years two to six, bringing the annual bill to not far off £500 during that period.

Insurance

The entry-level petrol 35 TFSI sits in group 23, while the 40 TFSI in Sport trim climbs to group 29. The 30 TDI starts from group 22 out of 50, while the range-topping diesel S line 40 TDI quattro is in group 30.

Warranty

Audi's warranty looks a little stingy in the face of its competition; its three-year/60,000-mile cover is pretty standard fare, with BMW and Mercedes providing unlimited-mileage cover over the same time period. The standard warranty can be extended to four years/75,000 miles for around £400 or five years/90,000 miles for just under £1,000.

Servicing

Audi offers fixed service intervals of 9,000 miles or once a year, or flexible servicing that can see drivers cover up to every 19,000 miles or two years for the major between services. Flexible servicing is recommended for drivers with a high annual mileage, while fixed servicing better suits town and city drivers making frequent, short trips. Audi offers owners a range of fixed-price service deals.