Thinking about buying a used Audi A6 (2000–2023) in New Zealand? We've documented 25 known faults for this model spanning engine, transmission, suspension, and cooling. Each researched and verified before it's published. The most serious issues here are rated critical. Two are set out in full below — the rest, with the symptoms, repair costs and checks for each, are free with an account.
25
Documented faults
Critical
Most serious
$1,600–$4,500
Typical repair
5
Systems covered
Known Audi A6 faults
Every fault below is documented specifically for this model — researched and verified before it’s published.
012.0 TDI CGLC Balance Shaft Chain Failure
CriticalCommonEngine $8,000–$22,000 to fix
The EA189 2.0 TDI (engine code CGLC) uses a secondary balance shaft chain driven off the crankshaft to eliminate second-order vibration. This chain, its hydraulic tensioner, and plastic guide rails are prone to stretching and failure at high mileage or under extended oil service intervals. As the chain elongates it takes the balance shaft out of phase, causing severe engine vibration and knock. Complete chain or guide failure allows the balance shaft to seize, destroying the oil pump drive integrated into the balance shaft module. Sudden oil pressure loss results in catastrophic main bearing and connecting rod damage requiring engine replacement.
Symptoms to notice
Severe engine knock or heavy low-frequency vibration particularly under load
Rattling or slapping noise from lower front of engine at start-up
Oil pressure warning light illuminating suddenly during driving
Check engine light with crankshaft or balance shaft correlation fault codes
Engine stalls without warning or will not restart after balance shaft seizure
What to check
Request full oil service history — intervals must have been under 10,000 km with VW 507.00 specification oil for CGLC health. Scan for crankshaft and balance shaft correlation fault codes. Listen for any rattling from the lower front engine area. Ask specifically about any history of rough running, vibration, or oil pressure warnings. On high-mileage examples above 150,000 km consider pre-purchase inspection with balance shaft chain access.
Where to look: Lower front of engine block — balance shaft chain runs between crankshaft sprocket and balance shaft module, accessed via oil sump removal
Ask the seller
“What has the oil change interval been and was VW 507.00 specification oil always used?”
“Has the vehicle ever shown engine knock, heavy vibration, or an oil pressure warning?”
“Has the balance shaft chain, tensioner, or guides ever been replaced or inspected?”
“Has the car ever stored crankshaft or balance shaft correlation fault codes?”
0248V mild-hybrid / start-stop faults and rough restarts
MinorOccasionalElectrical $600–$3,000 to fix
The C8 A6 uses a 48-volt mild-hybrid system with a belt-driven starter-generator that handles the frequent engine stop-start and coasting. Owners report harsh or slow engine restarts, start-stop dropping out, and occasional 12V/48V electrical warnings, sometimes traced to the auxiliary battery or the starter-generator. It rarely leaves you stranded but can be an expensive out-of-warranty diagnosis.
Symptoms to notice
Harsh or delayed engine restart from stop-start
Start-stop stops working
Electrical/battery warning messages
Jerky low-speed coasting-to-restart
What to check
In traffic let the engine stop-start several times and note whether restarts are smooth. Watch for electrical warning messages. Ask whether the auxiliary battery has been replaced and whether the mild-hybrid system has ever thrown faults.
Where to look: 48V belt starter-generator and batteries
Ask the seller
“Does stop-start work smoothly?”
“Has the auxiliary/48V battery been replaced?”
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23 more documented faults on the Audi A6
Symptoms, what to check, where to look and what to ask the seller — for every fault above. Free with an account, no card needed. One account covers one vehicle, so make it the car you’re actually looking at.
This page covers the model. Enter the plate of the actual car you’re looking at and see its year, engine, safety rating and register flags — free, no account needed.
Like any used car, it depends on the specific example and its service history. Across the 25 documented faults for the Audi A6, the recurring problem areas are engine, transmission, and suspension. A Audi A6 with a full service history and no signs of the issues listed on this page can be a sound buy but each one needs to be checked individually before you commit.
What are the most common problems with a used Audi A6?
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We've catalogued 25 known faults for the Audi A6, covering engine, transmission, and suspension. Two are written out in full on this page. The rest — with the symptoms to notice, what to inspect, and typical repair costs for each — are free once you create an account.
How much do repairs cost on a Audi A6?
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Most single repairs on the Audi A6 fall between $1,600–$4,500 at NZ independent-workshop rates. Some of the 25 documented faults cost less and a few cost considerably more, and no one car needs them all. Knowing which ones to look for before you view is what lets you negotiate the price down or walk away.
Should I get a pre-purchase inspection on a Audi A6?
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Yes. A Audi A6 inspection focused on its known weak points is the single best way to avoid an expensive mistake. KickTyres gives you a guided, model-specific inspection plus a market valuation and negotiation figure for $17.90 far less than the cost of missing one of the faults on this page.