Known faults for the Audi A4 (B7).

Engine / equipment

2.0 TFSI EA113 (Golf V GTI, A3/S3 8P, A4 B7, TT 8J, Leon Cupra, Octavia RS, Passat B6, Eos)

Period mentioned

2004–2013

Symptoms

Power loss or hesitation at full load, fuel pressure codes, high-pressure pump noise; fuel smell in the oil and a rising level if the pump leaks; misfires.

Possible cause described

A follower between the camshaft and the high-pressure fuel pump wears through and damages the cam lobe and the pump; Audi hardened the cam in 2006. The pump can leak fuel into the oil. There is also carbon build-up on the intake valves and coil pack failures.

Check for the garage

Check the high-pressure pump follower at every service, smell the oil and watch its level, and read fuel pressure with a diagnostic tool.

Cost cited in the source

Follower: approx. €250–900 depending on damage; far more if the camshaft or pump is damagedA rough figure from the original database, not an up-to-date quote.

Mileage cited in the database: from 90,000 km. This is not a maintenance interval and does not predict a failure.

Sources from the original database

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

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.

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

4.2 V8 40-valve (S4 B6/B7) and 4.2 FSI V8 (RS4 B7, S5 8T until 2011, RS5, R8, Q7 4L)

Period mentioned

2003–2015

Symptoms

Rattle from the rear of the engine on a cold start, misfires or an engine light for timing deviation; on FSI engines, power loss and rough idle from carbon build-up.

Possible cause described

The timing chains sit at the rear of the engine, against the bulkhead, with plastic guides and tensioners that crack; replacing them means removing the engine. FSI direct injection builds carbon on the intake valves from about 40,000–60,000 km.

Check for the garage

Listen to a cold start, read crank-cam correlation codes and inspect the intake valves with a borescope.

Cost cited in the source

Chains (engine out): approx. €6,500–11,000 on a Q7 4.2 FSI (converted from dollars); carbon cleaning: far lessA rough figure from the original database, not an up-to-date quote.

Mileage cited in the database: from 40,000 km. This is not a maintenance interval and does not predict a failure.

Sources from the original database