The entry-level diesel in the C6 A6 lineup, offering executive-class space with four-cylinder fuel economy. Two distinct engine generations were fitted: the PD (pumpe düse) units with engine codes BLB and BRE from 2004-2008, and the common rail CAGB from 2008-2011. The PD versions carry the well-known oil pump hex drive weakness shared across the VAG 2.0 TDI family, while the later common rail variant is generally more robust but was affected by the Dieselgate emissions recall. Available only with front-wheel drive, paired with either a 6-speed manual or the Multitronic CVT automatic.· more· less
Buy if: You find a post-2008 common rail model with manual gearbox and complete service history, or a PD version with confirmed oil pump hex shaft upgrade.
Avoid if: You are looking at a Multitronic CVT variant without documented fluid changes, or a PD engine with unknown oil pump hex shaft status.
Price & maintenance
Used price
€5,000
median asking price, typically 230,000 km
Typical range€3,600 – €6,400
Kilometres drivenAll
Maintenance cost
€850 – €1,700/year
at 15,000 km/year
Fixed costsservice, tyres, brakes€500 – €900 /yr
Risk bufferunplanned repairs€350 – €800 /yr
Price estimates are based on German asking prices. Prices and costs vary by vehicle condition and location.
Ownership costs
Maintenance assumes 15,000 km a year. Price estimates are based on German asking prices. Prices and costs vary by vehicle condition and location.
Hex drive connecting balance shaft to oil pump rounds off, causing sudden total loss of oil pressure · more· less
The PD-generation 2.0 TDI engines (BLB, BRE) have a balance shaft module driven by a hex bar that also drives the oil pump. This hex drive wears over time, and when it rounds off, oil pressure drops to zero instantly. If the warning light is ignored even briefly, the engine seizes and is destroyed. This is widely regarded as the number one failure mode of the VAG 2.0 TDI PD family. The issue typically manifests between 120,000 and 200,000 km, though some engines fail earlier. Preventive repair involves replacing the hex drive and balance shaft module. A specialist gear conversion kit (replacing the chain drive with gears) costs approximately €500-800 including labour. If the engine has already suffered damage, a replacement short block runs €2,500-5,000 depending on the extent of the damage. The later common rail CAGB engine (2008+) has a revised design that largely eliminates this weakness. Always verify which engine code your car has before purchasing.
Multitronic CVT gearbox failure
€1,500 - 4,5002 of 8
CVT chain stretches and mechatronic unit fails, causing juddering, slipping, and loss of drive · more· less
The Multitronic (0AN/01J) CVT is the only automatic option on the front-wheel-drive A6 C6 2.0 TDI. The CVT chain stretches over time, the friction clutch packs wear, and the mechatronic control unit can fail from overheating. Common symptoms include juddering at low speeds (30-50 km/h), RPM fluctuations, jerky takeoff, and the P R N D S lights flashing simultaneously on the dashboard. Problems typically appear between 100,000-180,000 km, with cars that have never had their gearbox oil changed being most vulnerable. Audi marketed the oil as a lifetime fill, but specialists universally recommend changes every 50,000-60,000 km. A mechatronic unit repair costs approximately €1,000-1,500. A full gearbox chain and clutch replacement runs €2,000-3,000 at a specialist. Complete gearbox replacement reaches €3,500-4,500. Post-2005 Multitronic units are considered more reliable than earlier versions, but the fundamental design remains a weak point. Manual gearbox models avoid this issue entirely.
Turbocharger failure
€1,200 - 2,5003 of 8
Oil starvation or carbon buildup causes turbo bearing failure, producing whining noise and smoke · more· less
The turbocharger on the 2.0 TDI can fail due to oil starvation (often related to the oil pump hex drive weakness on PD engines), carbon buildup from city driving, or simply high-mileage wear. Symptoms include excessive exhaust smoke, whining or screeching noises from the turbo area, loss of boost, and oily residue in the intercooler piping. The turbo typically lasts 150,000-250,000 km with proper maintenance, but can fail prematurely if oil change intervals have been extended. Replacement with a reconditioned turbo at an independent specialist costs €1,200-1,800. A new OEM turbo installed at an Audi dealer runs €2,000-2,500. On PD engines, turbo failure often follows oil pump hex drive issues, so both should be investigated if turbo problems develop.
EGR valve carbon buildup
€300 - 8004 of 8
Carbon deposits progressively block the EGR valve, especially on city-driven cars · more· less
The EGR system recirculates exhaust gases to lower NOx emissions but accumulates carbon deposits over time. Cars driven primarily in urban traffic are most affected. Symptoms include rough idle, slight loss of power, increased fuel consumption, and the engine management warning light. On the 2.0 TDI, the EGR valve is located at the rear of the engine, making labour-intensive replacement more expensive. Professional cleaning costs approximately €200-300. Full EGR valve replacement runs €400-800 including labour, depending on whether an independent shop or dealer performs the work. The issue is progressive and typically becomes problematic after 100,000-150,000 km. Regular motorway driving helps keep the system cleaner, as sustained high exhaust temperatures burn off carbon deposits. On CAGB engines that received the Dieselgate software update, some owners report accelerated EGR fouling.
DPF clogging from short-trip driving
€200 - 1,5005 of 8
Diesel particulate filter clogs when the car rarely reaches sustained motorway speeds for regeneration · more· less
The DPF requires regular passive regeneration at sustained highway speeds to burn off accumulated soot. Cars driven mainly on short urban trips (under 15 km) do not reach the temperatures needed for regeneration, causing progressive buildup. Symptoms include the DPF warning light, reduced power, increased fuel consumption, and eventually limp mode. A forced regeneration at a workshop costs €100-200. Professional DPF cleaning runs €300-500. If the filter is beyond recovery, replacement costs €800-1,500 including labour. Note that not all early C6 2.0 TDI models were fitted with a DPF - some PD engines (particularly BLB/BRE before 2006) were sold without one. Later models with the CAGB engine all have DPF fitted. On CAGB engines that received the Dieselgate software update, owners have reported increased regeneration frequency and DPF clogging.
Front suspension control arm bushings
€600 - 1,5006 of 8
Multi-link front suspension bushings wear, causing clunking noises and imprecise steering · more· less
The A6 C6 uses a complex multi-link front suspension with multiple aluminium control arms. The rubber bushings and ball joints in these arms wear over time, producing clunking or knocking sounds over bumps and uneven surfaces. Worn bushings also affect steering precision and can cause uneven tyre wear. The front suspension typically needs attention between 100,000 and 150,000 km, depending on road conditions. Replacing individual arms costs €80-200 per arm (parts) plus labour. A full front suspension overhaul kit with all 12 components (8 control arms, 2 tie rod ends, 2 anti-roll bar links) costs €300-500 for quality aftermarket parts (Meyle, Lemforder) or €800-1,200 for OEM Audi parts. Labour for a full front suspension rebuild runs approximately €400-600 at an independent shop.
Valve cover oil leak damaging timing belt
€300 - 2,5007 of 8
Oil leak from valve cover gasket can contaminate and weaken the timing belt if left unaddressed · more· less
The valve cover gasket deteriorates with age and heat, allowing oil to seep out. On the 2.0 TDI, this leak can drip onto the timing belt, causing the rubber to degrade prematurely. If the contaminated belt fails, the engine suffers catastrophic valve damage as it is an interference design. The valve cover gasket itself is inexpensive (€30-60 for the part), but the repair requires several hours of labour, costing €200-400 total. If the timing belt has been contaminated, it must be replaced along with the tensioner and water pump, adding another €400-700 to the bill. Total cost if caught late and the belt has failed is €1,500-2,500 for engine repair. This is preventable with regular visual inspections of the engine bay.
Electronic steering lock module (J518) failure
€400 - 1,2008 of 8
Steering lock module relay fails, preventing engine start and sometimes locking the steering mid-drive · more· less
The A6 C6 uses an electronic steering lock module (J518) that is a known weak point across the entire C6 platform. The internal relay fails over time, preventing the engine from starting or, in rare cases, locking the steering while driving. The fault code is 00288 - Steering Column Lock Actuator Defective. Audi dealer replacement involves the full steering column and runs €1,000-1,500. However, specialist repair services can replace the internal relay and micro-switches for €300-600, or a complete module refurbishment costs €400-700. The issue typically occurs between 100,000-200,000 km and affects all C6 A6 variants, not just the 2.0 TDI. A steering lock delete service is also available from specialists for €200-400.
Engine generation and gearbox choice define the ownership experience
The Audi A6 C6 2.0 TDI's reliability depends heavily on which engine version and gearbox it has. PD engines (BLB/BRE, 2004-2008) carry the serious oil pump hex shaft risk that demands preventive attention. The later common rail CAGB (2008-2011) is fundamentally more robust. On both versions, the Multitronic CVT automatic is a significant weak point that can be avoided entirely by choosing a manual gearbox. With the right combination (CAGB engine, manual gearbox) and regular maintenance, these cars can comfortably exceed 250,000 km. The wrong combination (PD engine, neglected Multitronic) can produce costly failures.
Service history
Complete Audi dealer or VAG specialist records essential. Verify oil change intervals (should be every 15,000 km or annually, not extended longlife intervals).
Tires
Check tread depth, age (date codes), and uneven wear patterns. Uneven front tyre wear suggests worn suspension bushings.
Cold start
Start the engine completely cold. Listen for unusual rattling, knocking, or metallic noises in the first 30 seconds.
Test drive
Drive for at least 30 minutes including varied speeds. On automatics, pay attention to gearbox behaviour at low speeds (30-50 km/h).
Specific for this vehicle
Identify the engine code
Check the sticker on the timing belt cover or use VCDS/OBD to confirm whether the engine is PD (BLB/BRE) or common rail (CAGB). This determines the oil pump hex shaft risk.
Check oil pressure at idle (PD engines)
If possible, connect a diagnostic tool and check oil pressure readings. Low oil pressure at idle is an early warning of hex drive wear. Also listen for any metallic ticking or low-end knocking.
Test the Multitronic CVT thoroughly (if automatic)
Drive at low speeds (30-50 km/h) and check for juddering. Accelerate from standstill and feel for hesitation. Check dashboard for flashing P R N D S lights. Ask for proof of gearbox oil changes.
+ 4 more checksShow less
Inspect valve cover area for oil leaks
Look along the entire edge of the valve cover for oil seepage. Check below the timing belt cover for oil contamination. A visible leak here requires immediate attention.
Check front suspension for play and clunking
Rock the front wheels at 12 and 6 o'clock and 3 and 9 o'clock positions to check for play. Drive over speed bumps and listen for clunking sounds.
Test the steering lock module
Turn the ignition on and off several times. If the car hesitates to start or the steering lock fails to disengage, the J518 module may be failing.
Verify Dieselgate recall status (CAGB engines)
If the car has the common rail CAGB engine, check with Audi whether the Dieselgate emissions update has been applied. Ask the owner about any changes in performance or fuel economy after the update.
Dieselgate emissions software update (2008-2011 CAGB engines)Verify status with Audi
Steering tie rod seal deterioration (selected production dates)Verify completed
Contact an Audi dealer with the VIN to verify all recalls have been completed. The Takata airbag recall is safety-critical. For CAGB engines, verify whether the Dieselgate software update has been applied and ask the owner about any post-update issues.
Warranty Status
Factory warranty (2 years)Expired on all A6 C6 models
Rust perforation warranty (12 years)Expired on most models (last C6 produced 2011)
Extended warrantyNo longer available from Audi for this age
All A6 C6 models are well outside their original 2-year factory warranty. The 12-year rust perforation warranty has also expired on most examples. Third-party warranty providers may offer coverage, but expect significant exclusions on a car of this age.
Sources: Research draws on model-specific owner forums and owner communities, recall information from official authorities, German automotive press, and multiple workshop cost references cross-checked against each other.
This report is for informational purposes only and does not constitute professional advice. Estimates may be inaccurate. Always have a qualified specialist inspect the vehicle before purchase. We accept no liability for decisions made based on this information.
