Audi A6 C6 vs Lexus IS II: which is more reliable?
According to the MotorFiable Score, the Audi A6 C6 (5.2/10) has fewer serious documented faults than the Lexus IS II (4.3/10), mainly because of their engines.
| Item | Audi A6 C6 | Lexus IS II |
|---|---|---|
| Segment | Saloon | Saloon |
| Years | 2004–2011 | 2005–2013 |
| MotorFiable Score | 5.2 out of 10 | 4.3 out of 10 |
| Engine score | 5.9/10 | 2.3/10 |
| Most recommended engine | Audi 3.0 TFSI V6 · With caution | 2.0/2.2 D-4D · Avoid |
| Score for the rest of the car | 4.5/10 | 6.3/10 |
| Suspension | 7.9 out of 101 faultHigh severity | 9.5 out of 100 faults |
| Brakes | 8.2 out of 100 faults | 8.0 out of 101 faultHigh severity |
| Gearbox and clutch | 3.3 out of 107 faultsHigh severity | No documented faults |
| Electrical system | No documented faults | 7.9 out of 101 faultHigh severity |
| Headlights and lights | 8.2 out of 101 faultMedium severity | 8.6 out of 100 faults |
| Airbags and safety | 7.1 out of 101 faultCritical severity | 7.1 out of 101 faultCritical severity |
Scores out of 10: the higher, the fewer serious documented faults. How we calculate them
Main faults of the Audi A6 C6
Outside the engine
- High severityFrequency: CommonGearbox and clutchWear and failures of the Multitronic automatic gearbox on front-wheel-drive versionsYes: on front-wheel-drive versions with the Multitronic (CVT) gearbox, gebrauchtwagenberater.de documents jerking when pulling away that can progress to complete failure, especially on older cars; fiches-auto.fr adds selector lock-ups and torque converter breakages. The quattro versions, with the Tiptronic gearbox, do not share this problem.Repair (garage): €1,000Appears at around 120,000 km
- Critical severityFrequency: OccasionalAirbags and safetyTakata recall: the front airbag can fragment in a crash (campaign 69EQ)Yes: campaign 69EQ covers A6, S6, A6 allroad quattro and RS6 models built between 23 February 2004 and 3 August 2011 because the Takata front airbag inflator can degrade with moisture and throw metal fragments when it deploys. The inspection and, where necessary, the replacement are free of charge at the official network.Repair: €0
- High severityFrequency: OccasionalSuspensionFailure of the adaptive air suspension compressor (equipped versions)On cars with the optional adaptive air suspension (standard on the allroad quattro), gebrauchtwagenberater.de documents compressor failures that can make the car settle completely; fiches-auto.fr records a case of the rear air springs being replaced along with the compressor.
In their engines
- Critical severityFrequency: CommonMultitronicWear 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: CommonMultitronicControl 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.
- High severityFrequency: Common3.0 TDI V6Failing 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.
Main faults of the Lexus IS II
Outside the engine
- Critical severityFrequency: OccasionalAirbags and safetyDefective gas generator in the Lexus IS driver's airbag (2019 alert)A May 2019 Safety Gate alert says the gas generator of the driver's front airbag in the Lexus IS built between 2010 and 2017 may be defective and release metal fragments when it deploys. Among the types listed is the XE2(a), that of the second-generation IS.
- High severityFrequency: OccasionalBrakesBrake fluid leak from the master cylinder rear seal (IS 250 and IS 220d)The UK's DVSA records a recall of 15,445 Lexus IS 250 and IS 220d: if an unsuitable brake fluid was used, the master cylinder rear seal could dry out and distort, with a fluid leak and the low-level warning light coming on. The seal was replaced with an improved one.
- High severityFrequency: OccasionalElectrical systemFront wiper arm nuts with insufficient tightening (2013 campaign)In 2013 the UK's DVSA recorded the recall of 15 left-hand-drive Lexus IS 220d and IS 250: the wiper arm nut could be left loose and, under a load such as accumulated snow, one or both wipers could stop working. The nuts were replaced.
In their engines
- Critical severityFrequency: Very frequent2.0/2.2 D-4DWarped cylinder head gasket and oil consumption on the 2.2 D-4DYes: the 2.2-litre block (2AD-FTV and 2AD-FHV D-CAT) has numerous documented cases of warped cylinder head gaskets and oil consumption or dilution in the Avensis, RAV4, Auris, Corolla Verso and Verso, with repairs that sometimes require replacing the engine.Appears at around 40,000 km
- Medium severityFrequency: Very frequent2.0/2.2 D-4DEGR valve clogged with sootYes: the EGR valve clogs with soot very frequently across the whole 1AD/2AD D-4D family, especially with urban use and short journeys, and it usually causes a loss of power or the engine warning light to come on.Appears at around 45,000 km
- Medium severityFrequency: Common2.0/2.2 D-4DInjector wear and failureYes: the common-rail injectors fail frequently in this family, with cases documented from 30,000 km and repairs ranging from €800 (one injector) to €1,900 (several) according to the owners consulted.Appears at around 30,000 km