Audi , A6 , C5 , 1.8 Turbo (2001-) Common Issues

Most Common (20-30% incidence rate)

1. Faulty Mass Airflow Sensor ($300-$500 repair)
2. Worn or Loose Fuel Pressure Regulator O-Rings ($200-$400 repair)
3. Leaking Oil Pan Gasket ($150-$300 repair)
4. Faulty Oxygen Sensors (both front and rear) ($100-$200 each, $400 total)
5. Ignition Coil Failure ($50-$100 per coil, up to 6 coils)

Moderately Common (10-20% incidence rate)

1. Power Steering Pump Failure ($500-$700 repair or replacement)
2. Rear Main Seal Leak ($300-$500 repair)
3. Faulty Fuel Pressure Regulator ($200-$400 repair)
4. Coolant Leaks from the Radiator, Water Pump, or Hoses ($100-$300 each)
5. Worn or Loose Timing Belt Tensioner Pulley ($50-$150 per pulley)

Less Common (5-10% incidence rate)

1. Faulty Turbocharger Compressor Wheel (Turbo Failure) ($800-$1,200 repair or replacement)
2. Faulty EGR Valve and Vacuum Hose ($100-$200 each)
3. Rear Differential Failure ($500-$700 repair or replacement)
4. Brake Master Cylinder Failure ($300-$500 repair or replacement)
5. Air Suspension Leaks or Failure (front or rear) ($200-$400 per leak)

Rare but Noteworthy Issues (< 5% incidence rate)

1. Faulty Engine Control Module (ECM) Replacement ($800-$1,000 repair)
2. Head Gasket Replacement due to Engine Overheating ($1,500-$2,500 repair)
3. Oil Leak from the Timing Chain Tensioner or Cover Seal ($300-$600 each)
4. Rear Axle Shaft Failure (both sides) ($400-$700 per shaft, $800 total)
5. Faulty Fuel System Pressure Sensor Replacement ($200-$300 repair)

Extreme and Rare Issues (< 1% incidence rate)

1. Engine Block Cracking due to Overheating or Other Causes ($3,000-$6,000 repair)
2. Complete Engine Failure (Turbo or Non-Turbo) Rebuild or Replacement ($4,000-$8,000 each, depending on parts and labor)
3. Transmission Failure or Rebuild (Automatic or Manual) ($2,500-$5,000)
4. Electrical System Malfunctions requiring ECM replacement and wiring work ($1,000-$2,000 repair)
5. Complete Vehicle Disassembly for Rebuild due to Extreme Wear or Failure ($8,000-$15,000 total cost)