2009 Audi S4

The 2009 Audi S4 is a performance sedan known for its blend of luxury and sporty driving dynamics. It was offered with a 3.0-liter supercharged V6 engine, producing 333 horsepower and 325 lb-ft of torque, paired with either a 6-speed manual or a 7-speed dual-clutch S tronic transmission. People often praise the S4 for its responsive engine, sharp handling, and comfortable interior. Common complaints include the potential for high maintenance costs, particularly as the car ages, and some reliability concerns.

Engine

3.0L Supercharged V6

• Timing Chain Tensioner Failure
  • Description/Symptoms: A rattling noise upon startup, especially when the engine is cold. This can lead to catastrophic engine damage if left unaddressed. The timing chain tensioners can fail, causing the timing chain to skip or break.
  • Solution: Replace the timing chain tensioners, timing chains, and guides.
  • Estimated Cost to Fix: $3,000 - $5,000+
  • Recalls: None Found
• PCV (Positive Crankcase Ventilation) Valve Failure
  • Description/Symptoms: Rough idling, whistling noise from the engine bay, oil leaks, and potential for increased oil consumption. The PCV valve regulates crankcase pressure. A failing PCV valve can cause a vacuum leak and lead to engine performance issues.
  • Solution: Replace the PCV valve.
  • Estimated Cost to Fix: $300 - $600+
  • Recalls: None Found
• Supercharger Issues
  • Description/Symptoms: Whining noise, loss of power, or complete supercharger failure.
  • Solution: Repair or replace the supercharger.
  • Estimated Cost to Fix: $2,000 - $5,000+
  • Recalls: None Found

Transmission

6-Speed Manual

• Clutch Failure
  • Description/Symptoms: Slipping clutch, difficulty shifting gears, and a high engagement point.
  • Solution: Replace the clutch disc, pressure plate, and throwout bearing.
  • Estimated Cost to Fix: $1,500 - $2,500+
  • Recalls: None Found

7-Speed S tronic (Dual-Clutch)

• Mechatronic Unit Failure
  • Description/Symptoms: Harsh shifting, delayed engagement, and transmission error messages. The mechatronic unit controls the shifting of the dual-clutch transmission, and its failure can cause significant drivability issues.
  • Solution: Replace or repair the mechatronic unit.
  • Estimated Cost to Fix: $2,000 - $4,000+
  • Recalls: None Found

Suspension

• Control Arm Bushing Failure
  • Description/Symptoms: Clunking noises from the suspension, especially when going over bumps. Vague steering and poor handling. The control arm bushings wear out over time, leading to excessive play in the suspension.
  • Solution: Replace the worn control arm bushings or the entire control arm assembly.
  • Estimated Cost to Fix: $500 - $1,500+
  • Recalls: None Found

Electrical

• Navigation/MMI System Issues
  • Description/Symptoms: Freezing, crashing, or complete failure of the Multi Media Interface (MMI) system. Intermittent operation of the navigation system, radio, and other infotainment features.
  • Solution: Software update, replacement of the MMI control unit.
  • Estimated Cost to Fix: $500 - $2,000+
  • Recalls: None Found
• Oxygen (O2) Sensor Failure
  • Description/Symptoms: Check engine light, poor fuel economy, rough idling.
  • Solution: Replace the faulty O2 sensor(s).
  • Estimated Cost to Fix: $200 - $500+
  • Recalls: None Found

Exterior

• Headlight Issues
  • Description/Symptoms: Foggy, cloudy or discolored headlights, malfunctioning LED running lights
  • Solution: Restore/replace the headlight lenses. Replace LED bulbs or entire assembly.
  • Estimated Cost to Fix: $200 - $1500+
  • Recalls: None Found

Interior

• Sunroof Issues
  • Description/Symptoms: Sunroof fails to open or close properly, gets stuck, or makes excessive noise.
  • Solution: Repair or replace sunroof motor, track, or related components.
  • Estimated Cost to Fix: $300 - $1,000+
  • Recalls: None Found

Summary

The 2009 Audi S4, while enjoyable to drive, can present owners with a variety of issues, some of which can be quite costly to repair. Engine-related problems, particularly those concerning the timing chain and PCV valve, are among the most severe and expensive. Transmission issues, especially with the S tronic, can also lead to significant repair bills. Suspension and electrical problems are more common and tend to be less expensive, but still require attention. Potential buyers should be aware of these issues and factor them into their budget when considering a used 2009 Audi S4. A thorough pre-purchase inspection is highly recommended.