Audi S4
3.0-litre TDI V6 with 347 hp for the S variant, EA897 Evo. Camshaft fracture from material defect affects early serial numbers (before 073951) — check service history and TPI-2043172 documentation before purchase. Maintenance-intensive: four-chain timing and rubber belt to the high-pressure pump need regular inspection.
S4 TDI — Autobahn express with diesel torque
Diesel in an S-model: controversial, but brutally effective on the highway. 700 Nm from 1,750 rpm, consumption under 8 L/100km possible. Sounds like nothing, feels like a fast company car — because that's exactly what it is. Anyone wanting sound and emotion is in the wrong place.
Engine Weaknesses 6
The V6 3.0 TDI has four timing chains that wear prematurely with poor maintenance. Rattling on cold start is the typical warning. Complete chain drive replacement costs approx. €3,000.
Symptoms: Rattling or clattering noises on cold start, timing chain warning in instrument cluster
On EA897 EVO engines with certain serial numbers (CRT 000001–073951), camshafts can break due to material defects. A break inevitably causes severe engine damage.
Symptoms: Sudden loss of power, rough running, engine stall without prior warning
Faulty plastic coolant control valves cause coolant loss. The plastic welded joint becomes porous and leaks. Repair costs are around €1,200–1,400.
Symptoms: Dropping coolant level, rising temperature, coolant loss without visible external leak
The AdBlue dosing valve and AdBlue tank are prone to failure. Warning messages in the instrument cluster often appear early. Replacement costs over €1,000, sometimes covered by goodwill.
Symptoms: AdBlue fault message in instrument cluster, power reduction as limp programme
Soot deposits on injectors cause scattered symptoms and rough running. Particularly common with short-trip use. Cleaning or replacement can cost several hundred euros.
Symptoms: Rough idle, increased fuel consumption, soot clouds from exhaust
The NOx sensor upstream or downstream of the SCR catalyst fails prematurely, triggering the engine warning light. Often repaired under goodwill; outside warranty approx. €300–600 replacement.
Symptoms: Engine warning light (MIL), OBD fault code P20EE or similar, exhaust after-treatment warning
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.