2006 Audi S4

The 2006 Audi S4 is a performance sedan/wagon/cabriolet that boasted a naturally aspirated 4.2L V8 engine producing 340 horsepower and 302 lb-ft of torque. Transmission options included a 6-speed manual and a 6-speed Tiptronic automatic. Owners generally praise the car’s powerful engine, sporty handling, and luxurious interior. Common dislikes include its relatively high running costs, complex maintenance, and potential for expensive repairs.

Engine

4.2L V8

• Timing Chain Tensioner Failure
  • Description/Symptoms: Rattling noise upon startup, especially when cold. Can lead to catastrophic engine failure if not addressed.
  • Solution: Replace timing chain tensioners, chains, guides, and potentially adjust the timing.
  • Estimated Cost to Fix: $3,000 - $6,000+
• Carbon Buildup
  • Description/Symptoms: Rough idle, hesitation upon acceleration, reduced fuel economy, check engine light.
  • Solution: Manually clean the intake valves by removing the intake manifold and walnut blasting.
  • Estimated Cost to Fix: $800 - $1500+
• Oil Leaks
  • Description/Symptoms: Oil spots on the ground, burning oil smell, low oil level. Common leak locations include valve cover gaskets, rear main seal, and oil cooler seal.
  • Solution: Replace the faulty gaskets or seals.
  • Estimated Cost to Fix: $200 - $1000+ depending on the location and severity of the leak.

Transmission

6-Speed Manual

• Clutch Failure
  • Description/Symptoms: Slipping clutch, difficulty shifting, high clutch pedal engagement point.
  • Solution: Replace clutch disc, pressure plate, and throwout bearing. Consider replacing the flywheel as well.
  • Estimated Cost to Fix: $1,200 - $2,500+

6-Speed Tiptronic Automatic

• Valve Body Issues
  • Description/Symptoms: Harsh shifting, delayed engagement, slipping between gears.
  • Solution: Replace or rebuild the valve body. Sometimes a fluid flush and adaptation reset can help, but this is usually a temporary fix.
  • Estimated Cost to Fix: $800 - $3,000+ depending on the extent of the damage and whether the valve body is replaced or rebuilt.

Suspension

• Control Arm Bushing Failure
  • Description/Symptoms: Clunking noise from the front suspension, especially over bumps. Poor handling and alignment issues.
  • Solution: Replace the worn control arm bushings or the entire control arm assembly.
  • Estimated Cost to Fix: $300 - $800+ per control arm.
• Damper/Shock Failure
  • Description/Symptoms: Bouncy ride, poor handling, leaking fluid from the shock absorber.
  • Solution: Replace the faulty shock absorbers or struts.
  • Estimated Cost to Fix: $200 - $600+ per shock/strut.

Electrical

• Battery Drain
  • Description/Symptoms: Dead battery, especially after sitting for a few days.
  • Solution: Diagnose and repair the source of the parasitic draw. Common culprits include aftermarket electronics, faulty door lock actuators, and a failing alternator.
  • Estimated Cost to Fix: $100 - $500+ depending on the complexity of the issue.
• Instrument Cluster Pixel Failure
  • Description/Symptoms: Pixels missing or fading on the instrument cluster display.
  • Solution: Replace the instrument cluster or have the display repaired.
  • Estimated Cost to Fix: $200 - $800+ depending on the repair method.

Exterior

• Door Lock Actuator Failure
  • Description/Symptoms: Door won’t lock or unlock with the key fob or interior switch.
  • Solution: Replace the faulty door lock actuator.
  • Estimated Cost to Fix: $200 - $400+ per door.

Interior

• Navigation System Failure
  • Description/Symptoms: The navigation system will freeze or malfunction.
  • Solution: Have the unit repaired, or replace it with an aftermarket unit.
  • Estimated Cost to Fix: $150-$1000+ depending on the repair option.

Recalls:

• NHTSA Recall Number: 05V297000
  • Component: FUEL SYSTEM, GASOLINE:DELIVERY:FUEL PUMP
  • Potential Number of Units Affected: 780
  • Summary: On certain vehicles, the fuel pump may develop an internal leak under certain conditions of operation. This condition could result in a fuel odor and/or reduced fuel pump output.
  • Consequence: Either of these conditions could lead to an engine stall, which could result in a crash.
  • Corrective Action: Dealers will replace the fuel pump.
• NHTSA Recall Number: 06V197000
  • Component: FUEL SYSTEM, GASOLINE:DELIVERY:FUEL RAIL
  • Potential Number of Units Affected: 573
  • Summary: ON CERTAIN VEHICLES EQUIPPED WITH A 4.2L ENGINE, THE FUEL RAIL MAY BE OF INSUFFICIENT LENGTH AND, UNDER CERTAIN CONDITIONS, THE FUEL RAIL MAY PULL AWAY FROM THE FUEL INJECTORS.
  • Consequence: THIS CONDITION CAN CAUSE A FUEL LEAK WHICH, IN THE PRESENCE OF AN IGNITION SOURCE, COULD RESULT IN A FIRE.
  • Corrective Action: DEALERS WILL INSPECT THE FUEL RAIL TO ENSURE THAT IT IS SECURELY ATTACHED. IF IT IS NOT, THE FUEL RAIL WILL BE REPLACED. THE RECALL IS EXPECTED TO BEGIN DURING JULY 2006. OWNERS MAY CONTACT AUDI AT 1-800-822-2834.
• NHTSA Recall Number: 17V027000
  • Component: AIR BAGS
  • Potential Number of Units Affected: 16
  • Summary: Audi of America, LLC (Audi) is recalling certain 2005-2007 A4, S4 and 2007 RS4 vehicles. The driver’s frontal air bag may explode during deployment in the event of a crash.
  • Consequence: An inflator explosion may cause sharp metal fragments to strike vehicle occupants resulting in serious injury or death.
  • Corrective Action: Audi will notify owners, and dealers will replace the driver’s frontal air bag module, free of charge. The recall began March 1, 2017. Owners may contact Audi customer service at 1-800-822-2834. Audi’s number for this recall is 69M1.

Summary

The 2006 Audi S4 is a desirable car with a potent engine and luxurious features but suffers from some notable reliability issues, especially related to the engine’s timing chain and carbon buildup, as well as transmission issues. Repairs can be costly, particularly for engine-related problems. Potential buyers should be aware of these common issues and budget accordingly for maintenance and repairs. Careful pre-purchase inspection and a thorough maintenance history review are highly recommended.