Audi A4 2005–2008Common problems, reliability & repair costs

Symptoms: Usually none until it's expensive — that's the trap. Late-stage signs are low fuel pressure codes (e.g., P0087/P0191), long cranks, and loss of power. The follower is a small hardened cap between the intake cam lobe and the high-pressure fuel pump plunger; its coating wears through, then the pump plunger machines into the camshaft.

Fix: Caught early, it's a ~$20–$40 follower swapped in about an hour. Worn through, you're into a new high-pressure fuel pump and intake camshaft — a four-figure job. The community-standard prevention is inspecting the follower every 20k–30k miles (or every other oil change). Later revised camshafts ('J' revision) wear slower but still need checks.

Sources: ShopDAP — VW/Audi 2.0T FSI cam follower and camshaft wear, ECS Tuning — FSI cam follower awareness, AudiForums — B7 2.0T cam follower failure (owner account)

Symptoms: Shudder or judder from a stop, rubber-band slipping under load, harsh engagement, and the classic warning: all PRNDS gear indicators flashing on the cluster, then limp mode. Faults can be mechanical (chain/variator wear) or the transmission control module inside the unit.

Fix: TCM repair or exchange runs low four figures; a worn-out unit needs a rebuilt or used transmission, which can exceed the value of the car. Regular Multitronic fluid changes help, but no maintenance schedule fully de-risks these. Quattro cars use a conventional 6-speed Tiptronic and don't have this problem.

Sources: ECU Testing — Audi A4/A6 Multitronic transmission ECU common fault, Audizine — B7 A4 Multitronic CVT failure thread, PistonHeads — 2008 A4 B7 Multitronic issues

Symptoms: Sudden rough idle, shaking, hesitation, flashing check-engine light with misfire codes on one or more cylinders. Coils often fail one at a time, weeks apart.

Fix: Replace all four coils (and plugs while you're in there) rather than chasing them one by one — they're plug-in parts and one of the easiest DIY jobs on this car. Audi ran an extended coverage/service campaign on coils for cars up to 2007; that window is long closed, but it tells you how common the failure was.

Sources: ShopDAP — bad ignition coils and misfires, 2.0T FSI, Audizine — A4 coil pack campaign discussion, Edmunds forums — Audi A4 ignition coil problems

Symptoms: Loud whistle or 'tea kettle' noise from the engine bay at idle, rough idle, strong vacuum on the oil filler cap (hard to remove with the engine running), boost leak and sluggishness, sometimes rising oil use.

Fix: Replace the PCV/oil-separator valve on the valve cover — a common, well-documented FSI failure and a reasonable driveway job. Note: the notorious piston-ring oil-burning problem you may have read about is mostly the NEXT generation (2009–2011 B8 TFSI); on the B7, oil consumption complaints exist but usually trace to the PCV or general wear.

Sources: ShopDAP — 2.0T FSI PCV valve failure (how it sounds), AudiForums — B7 2.0T FSI bad PCV poll, CarComplaints — 2008 A4 burns oil

Symptoms: Clunking or creaking over speed bumps and driveways at low speed, vague steering, uneven front tire wear. The multi-link front end has many small arms and ball joints that age together.

Fix: Replace worn arms/bushings — usually done as a full upper/lower kit per side once one goes, since the rest are the same age. Aftermarket complete kits keep parts cost sane; alignment required afterward. A known, near-universal B6/B7 aging pattern, not a defect.

Sources: 034Motorsport — B6/B7 control arm kit (notes the classic clunk), Audizine — front control arm bushings worn at 49k

Symptoms: None until deployment — degraded inflator propellant can rupture the metal housing in a crash, sending fragments into the cabin. This is the industry-wide Takata recall, and B7 A4s are included.

Fix: Free inflator replacement at any Audi dealer. Run the VIN at nhtsa.gov/recalls or Audi's recall lookup before buying, and confirm the work was actually completed — many older cars still have open recalls.

Sources: Audi USA — Takata recall information, NHTSA — Takata recall spotlight, Nick's Car Blog — Audi Takata recalls include B7s

Tools: Socket set with 10mm and hex/Torx bits, Torque wrench, Rags (fuel will drip), New HPFP seal/O-ring

1. With the engine cold, relieve fuel pressure and unplug the sensor connector at the high-pressure fuel pump on the driver's side of the head.
2. Disconnect the fuel lines at the pump, keeping rags underneath to catch residual fuel.
3. Remove the three bolts holding the HPFP and withdraw the pump straight out.
4. Pull the cam follower off the pump plunger (or out of the bore) and inspect the contact face — any wear through the black DLC coating to shiny metal means replace it; a hole through it means stop and inspect the camshaft lobe.
5. Seat the new follower, lubricate with fresh oil, install the pump with a new seal, and torque the bolts in stages.
6. Reconnect fuel lines and connector, then crank and check for leaks.

Tools: Coil puller or flathead screwdriver (gentle), Spark plug socket (long reach) + extension, Torque wrench

1. With the engine cold, remove the plastic engine cover.
2. Unplug each coil connector, then pull the coils straight up out of the plug wells.
3. Blow out the wells, then remove the old spark plugs with a long spark plug socket.
4. Install new plugs torqued to spec — do not overtighten into the aluminum head.
5. Press the new coils on until they click, reconnect, and refit the cover. Replace all four coils as a set.

Tools: Socket set / Torx bits, Small pick for hose clips

1. Confirm the diagnosis first: whistle at idle plus strong suction at the oil filler cap points to the PCV.
2. Remove the engine cover and locate the PCV/oil-separator unit on the valve cover.
3. Disconnect the breather hoses and unbolt the old PCV unit.
4. Clean the mating surface, install the new unit with its fresh gasket/seals, and reconnect the hoses.
5. Start the engine and verify the whistle is gone and the oil cap lifts with normal light resistance.