2005 Audi A4 problems

• Multitronic 01J (1999-2007)

  · 01J

  It is the generation with the most documented control unit failures, jerking when pulling away and chain wear; it is only worth considering if the gearbox oil change history is verified, there are no stored fault codes and a cold road test shows no jerks or noises.^[2][3]

  With caution

Faults that affect 2005 cars

• Critical severityFrequency: CommonTransmissionWear of the variator chain and conesYes: the variator uses a chain of more than 1,000 links between two pairs of cones that wears with mileage, especially if the oil is not changed regularly. Gebrauchtwagenberater ties the gearbox's reputation to "numerous total failures"; Schaeffler/LuK sells a kit to repair the chain.
• High severityFrequency: CommonElectronicsControl unit (TCU) failure and limp modeYes: the multitronic control unit, especially in the 01J code (up to 2007), is one of its best-documented weak points. Overheating with oil seeping into the control unit causes fault warnings and limp mode and, if ignored, can end up damaging the gearbox itself.
• Medium severityFrequency: CommonClutchJerking and vibration when pulling away from cold (multi-plate clutch)Yes: with no torque converter, the multitronic pulls away using an electronic multi-plate clutch that can jerk or vibrate, especially when cold, if its plates are worn or the oil no longer has the right properties. It is one of the most cited fault symptoms of this gearbox.

• 3.0 TDI EA896 generation 1, Euro 4 (BKN, BMK, ASB, CARA; 2003-2008)

  204–233 hp · BKN, BMK, ASB, CARA

  It is the oldest series and the one with the EGR that fails most, as Audi cites, plus the intake flaps on the Q7 and A8 of that period. It is a reasonable buy with a clear history of timing, cooling and EGR work.^[4][5][6]

  With caution

Faults that affect 2005 cars

• High severityFrequency: CommonCoolingFailing water pump and cooling system leaksOn the 3.0 TDI the water pump can fail and, from 2010, overheat to the point of damaging the engine (the A6 C6 guide cites a service action). Owners also cite coolant leaks from hoses, the regulating valve and the cooler.
• High severityFrequency: OccasionalTimingTiming chain stretch and tensioner wearOn the 3.0 TDI V6 the timing chain is at the gearbox end and its tensioner can lose tension: it rattles on a cold start and, if the chain stretches, the timing goes out and the engine is at risk. Replacing it means opening the engine and costs several thousand euros.
• High severityFrequency: OccasionalInjectionInjector wear (needle seat) and injection faultsGerman guides point to wear of the needle seat of the 3.0 TDI injectors: they stop closing properly, diesel drips into the cylinder and dilutes the oil. Smoke from the exhaust can be the warning, and reports on the 313 hp twin-turbo repeat injection faults.
• Medium severityFrequency: CommonEmissions controlFaulty EGR valve and EGR coolerOn the first-generation EA896 engines the EGR valve and cooler often fail: Audi talks about around 15% of units compared with 1-2 in every 1,000 in the second generation (a figure cited by Wikipedia). The cooler clogs with soot and can lose coolant.
• Medium severityFrequency: OccasionalIntakeWorn intake flaps (swirl) and intake manifoldOn V6 TDI engines from 2004 to 2010 the control of the intake (swirl) flaps can develop play and turn on the engine warning light with code P3134. Hella says the flap and actuator form one unit and are replaced together; on the Q7 4L it is the category owners cite most.

• 2.0 TFSI 200 hp (AXX, BWA, BWE, BPY)

  200 hp · AXX, BWA, BWE, BPY

  It is reliable if maintained; verify the cam follower and timing belt replacement.^[7][8]

  With caution

Faults that affect 2005 cars

• High severityFrequency: CommonFuelWear of the high-pressure pump cam followerYes: the 2.0 TFSI EA113's high-pressure fuel pump is driven by the camshaft through a follower (tappet) that wears; if it wears through it can damage the pump or the camshaft, so it should be checked and replaced as a preventive measure.Repair (garage): €250–€900Appears at around 90,000 km
• Medium severityFrequency: OccasionalIntakeCarbon build-up on the intake valves from direct injectionOn a direct-injection engine like the 2.0 TFSI the petrol does not wash over the intake valves and oil vapour from the crankcase builds up on them, causing rough idle, hesitation and loss of power; it is fixed with a professional clean.
• Medium severityFrequency: RareLubricationPCV crankcase ventilation valve and oil consumptionA fault in the PCV crankcase ventilation valve can cause excessive oil consumption, blue smoke and rough idle on the 2.0 TFSI; it is a replacement part, although there is no reliable frequency data.
• Low severityFrequency: OccasionalTurboTurbo diverter (blow-off) valve failureThe original turbo diverter (recirculation) valve can fail under boost pressure and cause pressure loss, whistling when accelerating and weak response; it is a cheap part and easy to replace.

• 2.0 FSI (EA113, 150 hp, 2003-2009)

  150 hp · AXW, BLR, BLX, BLY, BVX, BVY

  Gebrauchtwagenberater.de singles out the 2.0 FSI, along with the naturally aspirated 1.6, as one of the most reliable petrol engines in the Audi A4 B7. Even so, two faults recur across several models and are worth checking before buying: carbon build-up on the intake valves and ignition coil failure.^{[8][9][10][11][12]}

  With caution

Faults that affect 2005 cars

• Medium severityFrequency: CommonIntakeCarbon build-up on the intake valvesBecause petrol is injected directly into the chamber, the 2.0 FSI does not wash the intake valves the way a port-injection engine does. Gebrauchtwagenberater.de documents carbon build-up in the Audi A3 8P and Passat B6, with higher consumption and less power as the mileage rises.
• Medium severityFrequency: CommonIgnitionIgnition coil failureIgnition coils are the engine fault that owners of this 2.0 FSI report most often, in models as different as the Golf V, Passat B6, Leon II and Altea. They cause an unstable idle, the engine running on fewer cylinders and, at times, difficulty starting.
• Low severityFrequency: OccasionalEmissions controlBlocked EGR valveOn the 2.0 FSI the EGR valve gets stuck or blocked fairly often, ending in a fault with the exhaust gas recirculation valve. It is a manageable repair with no risk to the engine, but it should be confirmed with diagnostics.

• Critical severityFrequency: OccasionalAirbags and safetyCampaigns over the Takata front airbag gas generatorsYes: the A4 B7 is included in campaign 69EQ, which covers cars built between 23 February 2004 and 3 August 2011 because the front airbag inflator can degrade and throw metal fragments when it deploys. fiches-auto.fr also documents a December 2020 campaign for a different risk, moisture getting into the generator, for cars from 2005 onwards.Repair: €0
• High severityFrequency: OccasionalSuspensionBreakage of the aluminium front suspension armsOn the 1.9 TDI versions, fiches-auto.fr documents fractures of the aluminium front suspension arms from 180,000-210,000 km, a safety fault because it can affect the car's directional control.Appears at around 180,000 km
• Medium severityFrequency: CommonGearbox and clutchEarly wear of the clutch and dual-mass flywheel (diesel)Several owners of 1.9 TDI versions document clutch and dual-mass flywheel faults on fiches-auto.fr between 75,000 and 160,000 km, with combined repairs of up to around €2,000 when both have to be replaced at the same time.Repair (garage): €1,000–€2,500Appears at around 75,000 km
• Medium severityFrequency: OccasionalSteeringPower steering pump failure and rack wearfiches-auto.fr records power steering pump failures (with vibration in the steering wheel at idle) and the 2008 TÜV report cited by gebrauchtwagenberater.de occasionally found defective steering racks on the A4 B7.
• Low severityFrequency: CommonElectrical systemBreakage of the electric window regulator mechanismsfiches-auto.fr documents frequent breakage of the electric window regulator mechanism, especially in the front doors, with testimonials between 90,000 and over 240,000 km and a cost of around €220-250 per mechanism.Repair (garage): €220–€250Appears at around 90,000 km