Audi A6 C7 vs Mazda MX-5 IV: which is more reliable?
According to the MotorFiable Score, the Mazda MX-5 IV (6.8/10) has fewer serious documented faults than the Audi A6 C7 (5.5/10), mainly because of the faults in the rest of the car (suspension, brakes, electronics…).
| Item | Audi A6 C7 | Mazda MX-5 IV |
|---|---|---|
| Segment | Saloon | Saloon |
| Years | 2011–2018 | 2015–today |
| MotorFiable Score | 5.5 out of 10 | 6.8 out of 10 |
| Engine score | 6.3/10 | 7.5/10 |
| Most recommended engine | 2.0 TDI · Buy | Skyactiv-G · Buy |
| Score for the rest of the car | 4.7/10 | 6.2/10 |
| Suspension | 8.2 out of 103 faultsMedium severity | 8.8 out of 100 faults |
| Brakes | 8.0 out of 101 faultCritical severity | 7.9 out of 100 faults |
| Gearbox and clutch | 3.6 out of 106 faults | 7.1 out of 101 faultCritical severity |
| Electrical system | 9.3 out of 101 faultLow severity | 7.1 out of 101 faultCritical severity |
| Electronics and infotainment | No documented faults | 8.6 out of 101 faultMedium severity |
| Climate control | 9.6 out of 101 faultLow severity | No documented faults |
| Bodywork and interior | 7.5 out of 100 faults | 8.2 out of 101 faultMedium severity |
| Airbags and safety | No documented faults | 8.6 out of 101 faultMedium severity |
Scores out of 10: the higher, the fewer serious documented faults. How we calculate them
Main faults of the Audi A6 C7
Outside the engine
- Critical severityFrequency: OccasionalBrakesBrake servo damaged by oil entering from the vacuum lines (2012 campaign)Safety Gate/RAPEX circulated in September 2014 (alert 37/2014) a recall of the Audi A6 Avant and Allroad (C7) built between March and December 2012: in isolated cases, oil can enter the brake servo through the vacuum hoses, damage the diaphragm and reduce braking force.
- Medium severityFrequency: OccasionalSuspensionPremature wheel bearing wearAccording to testimonies collected by fiches-auto.fr, there are cases of wheel bearings replaced between 85,000 and 193,000 km on the A6 C7. You notice it as a hum that grows with speed.
- Medium severityFrequency: RareSuspensionRear air suspension leaks and compressor failureAccording to testimonies collected by fiches-auto.fr, some A6 C7 cars with air suspension lose air in the rear bellows or need a new compressor, with cases from around 80,000 km. It is a fault cited by few owners.
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 Mazda MX-5 IV
Outside the engine
- Critical severityFrequency: OccasionalGearbox and clutchUnintended downshift of the automatic gearbox caused by a transmission control unit software faultA 2019 recall affects MX-5 ND models with the automatic gearbox built between October 2016 and November 2018: faulty software could make the gearbox downshift without the driver asking it to and lock the rear wheels. It is corrected by reprogramming the gearbox control unit.
- Critical severityFrequency: OccasionalElectrical systemDC/DC converter control unit fault with risk of short circuit and fireA 2018 Safety Gate alert covers MX-5 ND models built between August 2014 and April 2017: the DC converter control unit could fail, cause a short circuit and damage the converter, with a risk of fire. It is a precautionary recall; check the chassis number at the official service centre.
- Medium severityFrequency: OccasionalBodywork and interiorUnderbody protective panel coming away on the first vehicles built in 2015A 2019 recall affects MX-5 ND models built between 26 May and 6 July 2015: the fixing of the underbody protective panel was insufficient and it could come loose, fall onto the road and damage tyres or put traffic behind at risk.
In their engines
- Medium severityFrequency: OccasionalSkyactiv-GIntake shut-off valve software issue and engine stallingOn Mazda3 BM/BN units built up to 4 July 2018, incorrect ECU programming can deposit soot on the intake shut-off valve to the point of suddenly stalling the engine; Mazda fixed it with a software update.
- Medium severityFrequency: OccasionalSkyactiv-GMicro-cracks in the fuel pump impellerBetween October 2017 and May 2020, Mazda built Mazda3 and CX-5 units with a fuel pump whose impeller can crack, swell and end up cutting off the fuel supply with the engine running; the manufacturer recalled the affected cars.
- Medium severityFrequency: OccasionalSkyactiv-GECU programming and loss of power (CX-5 II and Mazda3 IV)On the CX-5 II built between 2017 and 2019, and the 2019 Mazda3 IV, incorrect engine ECU programming can cause loss of power or the engine to stall; Mazda fixes it with a software update acknowledged by Germany's KBA.