Known faults for the Audi A6 (C7).

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.

Sources from the original database

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.

Sources from the original database

Engine / equipment

2.0 TFSI in the Audi A4 (B8), A5 (8T), Q5 (8R) and A6 (C7)

Period mentioned

2012–2014

Symptoms

Engine warning light, coolant level warning, a heater that barely warms, a higher than normal temperature and limp mode; sometimes also automatic gearbox faults.

Possible cause described

One of the coolant control valves (N82, N509 or N488) leaks, and the coolant enters the wiring harness through its connector and reaches several control units; codes P275300 or P275500 may appear in the gearbox. Audi describes it in bulletin 01 15 31 (July 2015).

Check for the garage

With a high temperature, stop and do not drive on; do not open the reservoir when hot. At the garage, have them check the coolant valves and their connectors, and whether fluid has entered the harness, before replacing control units.

Cost cited in the source

No verified estimate; ask the garage for a quote.A rough figure from the original database, not an up-to-date quote.

Sources from the original database

Engine / equipment

1.6 and 2.0 TDI (EA189 and EA288)

Period mentioned

Approx. 2010–2020

Symptoms

Coolant level drops with no visible leak, white smoke with a sweet smell, rising temperature or engine light. In severe cases the engine hydrolocks.

Possible cause described

The internal tubes of the EGR cooler crack and coolant enters the intake. It worsened after the post-Dieselgate software update, which increased EGR use.

Check for the garage

Cooling system pressure test and check for coolant in the intake or manifold.

Cost cited in the source

€400–1,300A rough figure from the original database, not an up-to-date quote.

Sources from the original database

Engine / equipment

2.7 and 3.0 TDI V6 (EA896 and EA897): Audi A4, A5, A6, A7, A8, Q5, Q7; VW Touareg, Phaeton and Amarok; Porsche Cayenne, Macan and Panamera

Period mentioned

2004–2018

Symptoms

Chain rattle for the first seconds after a cold start; power loss or limp mode from the intake flaps; coolant or oil loss in the engine V; EGR faults with rough idle.

Possible cause described

The timing chains sit at the rear of the engine, against the bulkhead, and their tensioners lose pressure. The intake flaps use plastic linkage rods that wear. The coolant valve, oil cooler gasket and EGR are packed into the engine V and leak with age.

Check for the garage

Listen to a cold start (a rattle lasting more than 2–3 seconds is a bad sign), check flap operation with a diagnostic tool, look for leaks in the engine V and check the oil change history.

Cost cited in the source

Tensioners and chains: approx. €2,000–4,500; EGR with cooler: €1,000–1,500; oil cooler gasket: €300–600A rough figure from the original database, not an up-to-date quote.

Mileage cited in the database: 100,000–150,000 km. This is not a maintenance interval and does not predict a failure.

Sources from the original database

Engine / equipment

4.0 TFSI V8 twin-turbo (S6, S7, RS6 and RS7 C7, S8 D4)

Period mentioned

2012–2018

Symptoms

Hard starting, damaged turbo (smoke, power loss), oil consumption and misfires.

Possible cause described

The mesh strainer in the turbo oil feed, inside the engine's V, can clog and starve the turbos of oil. Audi issued a bulletin (2018, revised in 2021) with an optimised strainer and a check valve. Early engines also consume oil.

Check for the garage

Confirm whether the turbo oil strainer bulletin was applied, measure oil pressure and run an oil consumption test.

Cost cited in the source

Turbos: several thousand eurosA rough figure from the original database, not an up-to-date quote.

Sources from the original database