Audi Known Faults
Germany
44
Known Faults
Models
Most Reported Faults
DPF Blockage
ModerateThe A4 B8 TDI is frequently used as a company car on short local journeys rather than motorway runs. DPF blockage is the most common ownership complaint.
Turbocharger Failure
SevereTurbocharger failure on the B8 A4 TDI mirrors the wider VAG TDI pattern — oil sludge in the feed pipe causes bearing failure, often presenting as a sudden loss of boost.
Timing Belt Failure
CriticalThe B8 A4 2.0 TDI uses a timing belt with a 140,000-mile service interval. Many specialists recommend 100,000 miles. Belt failure is catastrophic on this interference engine.
EGR Cooler Failure and Coolant Loss
SevereEGR cooler failure is common on the B8 A4 TDI. Internal corrosion allows coolant to leak into the intake — initially causing rough running and white smoke.
Injector Failure
SevereHigh-mileage A4 B8 TDIs suffer injector wear, causing rough running, smoke and diesel contamination of engine oil.