Audi S4
EA897 evo (3rd generation 3.0 TDI), fitted from 2016 in A4 B9, A6 C8 and Q5 FY. The fully electronically controlled oil pump deliberately reduces pressure at idle — a design feature that can become a liability with age. Camshaft failures and low oil pressure are known major damage patterns.
354 hp company car — objectively fast, subjectively empty
Fast, quiet, completely sterile. Active Sound from the speakers instead of real V6 noise, steering that informs but never communicates, AWD that delivers traction without ever being noticed. Objectively better than the B7 at everything except making you feel something. The right car for a fast commute — the wrong car for a driving experience.
Engine Weaknesses 5
The ECU-controlled oil pump reduces pressure at idle to approx. 1.0–1.4 bar. At high motorway oil temperatures with bearing wear, this pressure is insufficient — con-rod bearings seize from 150,000 km.
Symptoms: Oil pressure warning at idle or on country roads, knocking noises, in severe cases engine failure
All 272-hp variants built before January 2017 contained faulty camshafts. Tooth flank noise and fractures are possible; Audi acknowledges the problem, goodwill depends on mileage.
Symptoms: Clattering or ticking from camshafts even after brief warm-up, rough running, in severe cases sudden engine stall
The EA897 uses four timing chains — one per cylinder bank, one connecting chain and one for the oil pump. All chains, tensioners and guides must be renewed together.
Symptoms: Rattling on cold start, metallic knock on throttle, engine light with camshaft faults
Injector failures with oil dilution from fuel ingress. Less common on EA897 evo than predecessors, but costly to repair: replacing multiple injectors can cost €4,000.
Symptoms: Rough engine, rising oil level (fuel ingress), heavy soot production, increased consumption
The 3.0 TDI in the SQ5/S4 B9 needs sufficiently long runs for DPF regeneration. Predominantly short-trip use accumulates ash in the filter. Above 45 g load, ceramic melting is at risk.
Symptoms: Engine warning light 'particulate filter system fault', noticeable power reduction (limp mode), increased fuel consumption. DPF regeneration runs more frequently and for longer.
Vehicle Weaknesses 15
Recall 42L1/42L5: Stress corrosion cracking in the rear trailing arm can increase play. Affected: build years 2019–2021. Missing wheel alignment after the initial recall caused severe rear tyre wear.
Recall 74E3 for S4 B9 (build years 2018–2020): a seat heater wiring fault can cause an occupancy sensor error and deactivate the front passenger airbag.
The Virtual Cockpit freezes or shows only the speedometer and tachometer during driving. The problem recurs even after software updates. A full digital cockpit replacement is expensive.
At higher mileages, worn wheel bearings and failed ball joints are documented. MOT testers regularly flag suspension geometry faults. Repair including wheel alignment costs around €800–1,500.
The optional electronically controlled suspension shows sporadic fault messages and damper failures. A single adaptive damper costs €500 net and upwards.
The S4 B9 TDI suffers from a software-related hesitation on pull-away: the engine revs to 2,000–2,500 rpm with no forward movement, then power arrives abruptly. Caused by WLTP gearbox calibration. Reduced in Dynamic mode.
The B9 develops coolant leaks from flanges in the cooling circuit. Plastic weld seams can crack — in severe cases overheating is a risk.
On the S4 B9 TDI, AdBlue injector nozzles can block through crystallisation or the urea pump can fail. After a fault message, a countdown to engine lock-out begins.
The S4 B9 shows increased brake disc wear during spirited driving. A complete front-and-rear set in OEM quality costs around €900–2,750.
The MMI system frequently has problems with Bluetooth, CarPlay and online connectivity. A software update is often sufficient, but occasionally a control unit swap is needed.
The ZF 8HP torque-converter automatic shows delayed shifting and judder on pull-away when cold. Audi sometimes describes this as 'state of the art'. A gearbox oil change can help.
On the optional panoramic roof, water drain channels can block or hoses detach, allowing water into the footwell or down the A-pillar.
The optional B&O premium sound system is prone to sporadic audio cut-outs due to control unit software errors. Voltage drops in cold conditions can crash the chip.
Rear wheel bearings on the S4 B9 can wear prematurely — accelerated by spirited driving and the quattro all-wheel-drive system. Cases documented below 80,000 km.
Annoying creaks and rattles in the dashboard and door panel area, sometimes occurring after only a short time. Workshop visits often provide no lasting fix.