KNOWN FAULTS · Audi

Audi A6 (C6) 2.0 TDI common problems.

2004–2011 · Diesel

Sources are not verified in real time and no entry confirms that your car is affected.

4 known faults with sources

PD TDI camshaft, injectors and cylinder headInjection / cylinder head

Engine / equipment: 1.2, 1.4, 1.9 and 2.0 TDI unit-injector (PD) engines, including the VW-sourced 2.0 CRD in Chrysler, Dodge and Jeep
Period mentioned: 2000–2010
Symptoms: Growing noise from the cylinder head, power loss and rough running (cams and lifters); unstable idle, smoke or hesitation (injectors); on the 16-valve 2.0 TDI, coolant loss with no visible leak from a cracked head.
Possible cause described: The camshaft also drives the unit injectors and carries a heavy load: without VW 505.01 oil the lobes and lifters wear. 2.0 TDI PD injectors fail frequently. Some 16-valve 2.0 TDI heads (part number ending in A) crack; VW considered it fixed by the end of 2006.
Check for the garage: Check the oil history (VW 505.01), listen to the head, check injector balance rates with a diagnostic tool and, on the 16-valve 2.0 TDI, read the head part number (03G 103 351) and look for coolant loss.
Cost cited in the source: Camshaft and lifters: approx. €400–800; 2.0 TDI PD injectors: €900–2,000A rough figure from the original database, not an up-to-date quote.

Mileage cited in the database: 120,000–200,000 km. This is not a maintenance interval and does not predict a failure.

Applies if: Only if fitted with the air conditioning system described.

A/C not cooling: N280 valveClimate control

Engine / equipment: Air conditioning with clutchless compressor and N280 regulating valve (combustion VW, Audi, Seat, Cupra and Skoda from 2006)
Period mentioned: 2006–2026
Symptoms: The air does not cool or cools intermittently (for example only at motorway speed), and sometimes the compressor rattles with the A/C on. Codes 01232 (N280 valve), P2612 or 00898.
Possible cause described: The compressor regulates its output with the N280 solenoid valve, its most common failure point. Audi issued technical bulletins over a manufacturing fault in this valve on Sanden compressors. Its connector can also become brittle and corrode (especially without the engine undertray), or the wiring fails.
Check for the garage: Read the codes and N280 control current with VCDS or ODIS, measure its resistance (about 10 ohms) and check the connector and wiring before replacing parts. If the valve or compressor is replaced, the whole circuit must be flushed.
Cost cited in the source: N280 valve: a cheap part (about 30 dollars) where sold separately; new compressor with circuit flush: considerably moreA rough figure from the original database, not an up-to-date quote.

Applies if: Only if fitted with the automatic gearbox described in the record.

Audi Multitronic (CVT) gearboxAutomatic gearbox

Engine / equipment: Multitronic continuously variable gearbox (01J and successors) in front-wheel-drive Audis: A4 B6/B7/B8, A5 8T and A6 C5/C6/C7
Period mentioned: 2000–2014
Symptoms: Judder or vibration when pulling away (especially uphill), a slipping feeling at low revs, jerky acceleration and limp mode with limited speed; sometimes a burning smell.
Possible cause described: Known failures of the variator chain and pulleys, the hydraulic and electronic control unit and the clutch pack. Audi issued service bulletins, and forums report failures even with the recommended fluid changes, although poor maintenance speeds them up.
Check for the garage: Read the gearbox codes with Audi-compatible equipment, check the fluid change history and, at a specialist, judge whether fluid and a clutch adaptation are enough or the control unit or variator needs repair. With limp mode or a burning smell, stop driving.
Cost cited in the source: A UK specialist says a judder checked early usually costs a few hundred pounds, while ignoring it can end in a full rebuild.A rough figure from the original database, not an up-to-date quote.

Applies if: Only the 2.0 TDI pump-injector from 2005–2009.

Worn hexagonal oil pump shaft on the 2.0 TDI pump-injector (2005–2009)Engine

Engine / equipment: 2.0 TDI pump-injector: VW Passat and Sharan, Audi A4 and A6, Škoda Superb and Seat Alhambra from 2005–2009
Period mentioned: 2005–2009
Symptoms: The oil pump stops working all at once, nearly always at high revs. The red oil pressure warning light comes on when the damage is already done.
Possible cause described: AUTO BILD (May 2013): the hexagonal shaft that drives the oil pump wears and can end up spinning freely; VW puts it down to “tolerance deviations”. Without oil at least the turbo is ruined, and often the whole engine. VW and Škoda confirmed cases “in the three-digit range” and review each case for a goodwill contribution. The group's other 2.0 TDI engines have a different pump drive.
Check for the garage: If the oil pressure warning light comes on, stop the engine as soon as you can and do not drive on. VW does not recommend a preventive repair; if you want one, the balance shaft module, which holds the shaft, is replaced. If the engine has already failed, ask the brand for a goodwill contribution.
Cost cited in the source: €1,300 to €1,700 for the balance shaft module at the dealer; an independent workshop replaced just the shaft and its seat from €650 (AUTO BILD, 2013).A rough figure from the original database, not an up-to-date quote.