Audi A5 40 TDI B10

The A5 B10 is among the first vehicles on Audi's new PPC platform with CARIAD E3 1.2 software. Early owners report multiple software-related issues: random dashboard warning lights combined with steering vibration (resolves with power-cycle), driver assistance systems becoming inoperative during mild weather conditions, infotainment screen freezing, and aggressive phantom braking from the emergency braking system. One owner on Audi Owners Club UK reported their 2025 A5 TDI Avant showed faults 4 times in 19 days, with the dealer acknowledging it affects a small number of vehicles while Audi develops a fix. A multi-module software update (TSB 2079690, known as the KD2 update) flashes approximately 30 control modules and addresses many of these problems. The financial cost is typically zero under warranty, but out-of-warranty diagnostic charges of €150-500 per visit could accumulate on older examples.

The B10 uses a second-generation MHEV plus system with the powertrain starter-generator (PSG) integrated on the transmission output shaft, unlike the belt-driven system in earlier 48V Audis. The older 48V BSG in A6/A7/A8 models has well-documented failures causing complete electrical shutdown while driving, with some owners reporting loss of steering, brakes, and all electrical systems. Audi extended warranty coverage on the older BSG system for 7 years (via service campaign 27BQ), suggesting awareness of the design weakness. Replacement of the 48V starter-generator costs €2,000-3,500 including labor. The MHEV plus design is different (output-shaft mounted vs belt-driven), which may improve or worsen reliability. Insufficient field data exists to determine failure rates. Symptoms of impending failure include intermittent start-stop malfunction and 48V battery charging warnings.

Despite improvements in the EA288 evo, the DPF still requires sustained exhaust temperatures (350-600 degrees Celsius) for regeneration. The MHEV plus system may slightly exacerbate this because electric coasting cools the exhaust system during motorway driving. Active regeneration occurs every 750-1,000 km or when soot loading exceeds 45%. Cars driven primarily on trips under 15 km accumulate soot faster than the system can burn off. A forced regeneration at a workshop costs €150-400. Professional chemical cleaning runs €400-800. Full DPF replacement costs €1,500-2,500. Use a diagnostic tool (OBDeleven or VCDS) to check the DPF soot loading percentage before purchase. Regular motorway runs of 30+ minutes at moderate RPM prevent this issue entirely.

The EA288 evo uses selective catalytic reduction with AdBlue injection to meet Euro 6d emissions standards. The AdBlue injector is prone to urea crystallization at the tip from thermal shock, particularly on vehicles with low annual mileage or predominantly city driving. This was identified in 2023 field data (service bulletin WSC-2022-08) and an updated injector with revised ECU calibration is available. A failed NOx sensor costs €350-700 to replace. The dosing module runs €500-900. The complete SCR system replacement reaches €1,200-1,800. The system triggers a countdown warning when it detects a malfunction, eventually preventing engine restart. The EA288 evo hardware is improved over earlier EA288 variants, but the issue persists for low-mileage city-driven vehicles.

The DL382+ is a wet-clutch 7-speed dual-clutch unit designed for longitudinal engines handling up to 500 Nm. It is significantly more reliable than the older dry-clutch DQ200, but the mechatronic unit can develop speed sensor failures (P0718), clutch slip under load (P0811), and parking lock malfunctions (P179F) at higher mileages, typically 80,000-120,000 km and beyond. Symptoms include jerky low-speed shifts, delayed engagement from standstill, and gearbox malfunction warnings on the dashboard. Mechatronic repair at a specialist runs €1,500-2,500; full unit replacement at Audi costs €3,000-4,000. Despite Audi's 'lifetime fill' claim, the transmission benefits from fluid changes every 60,000-80,000 km. Given the B10's youth, this is unlikely to affect first owners but relevant for used buyers at higher mileages.

The EA288 evo uses a low-pressure EGR circuit with an aluminium cooler that can develop micro-cracks from thermal cycling, primarily affecting vehicles used for towing or sustained high-speed driving. Symptoms include gradual coolant loss without visible external leaks, white exhaust vapour, and elevated DPF soot accumulation from coolant contamination. Replacement of the EGR cooler assembly costs €800-1,600 depending on whether the DPF and intake require decontamination. This typically appears after 80,000+ km of high-load use. Most standard-use cars will never experience this issue.