Workshop Manuals Factory service & repair Audi

Audi common faults and how to fix them

Faults that are well known on Audi models we hold manuals for: what the owner notices, what causes it, and the pages in our manuals that cover the repair.

Audi 4.2 timing chain: worn guides and tensioners on the S4 and other 4.2 V8s

Symptoms

A rattle from the back of the engine that lasts longer than the normal second or two after a cold start, then becomes constant. The engine light may come on with camshaft position or correlation codes, and the engine can run roughly. If a guide breaks and the chain jumps, the valves hit the pistons.

Cause

The 4.2 V8 drives its camshafts with chains at the rear of the engine, facing the bulkhead. On the B6 and B7 S4 the plastic chain guides, the tensioners and the camshaft adjusters wear and break, with owner clubs reporting failures from around 100,000 miles; the chains themselves rarely snap. Owner clubs report the same layout and wear pattern on the later 4.2 FSI in the A6, A8, Q7, S5 and RS 4.

Fix

A short rattle at cold start is the camshaft adjusters filling with oil and is normal. A longer or louder one needs the cam timing checked with a diagnostic tool. Because the Audi 4.2 timing chain covers are at the back, replacing the guides and tensioners normally means taking the engine out, with special tools to lock the camshafts. The 4.2 FSI timing chain procedure shows the locking pins and adapters. Replace guides, tensioners and any worn adjusters together.

Repair instructions on this site

Sources: Audizine — B6/B7 S4 timing chain FAQ; AudiWorld — 4.2 V8 forum.

Audi PCV valve: 2.0T whistle, rough idle and lean codes (2006–2010)

Symptoms

The engine light comes on with P2187 or P1297 (too lean at idle) or P2279 (intake air leak). There may be a whistle or rushing-air noise from the engine, a rough idle, and oil weeping from the oil filler cap. In very cold weather the idle can be uneven, or the engine stalls just after a cold start. It affects the 2.0T in the A3, TT, TTS and A4.

Cause

The 2.0T vents crankcase gases through a pressure regulating (PCV) valve on top of the engine. Its diaphragm splits or the valve sticks, so unmetered air enters the intake and crankcase pressure rises. Audi ran a required update (bulletin 17-09-03) to replace the valve, and later bulletins cover the whistle and oil leak (17-10-02) and freezing in cold weather (17-09-16).

Fix

Check whether Audi PCV valve update 17-09-03 has been done. If the codes or noise are present, the A3 PCV valve bulletin replaces the valve with the revised part. For stalling only in freezing weather, follow the cold-weather PCV bulletin: the cause is condensed water freezing in the breather, not a split diaphragm. Clear the codes afterwards and check the fuel trims at idle.

Repair instructions on this site

Sources: Audi technical bulletins 17-09-03, 17-10-02 and 17-09-16.

Audi water pump: coolant leak on the 3.2 V6 in the A5 and Q5 (2008–2010)

Symptoms

Coolant loss with no obvious puddle, a coolant smell after driving, a low coolant warning, or dried coolant crust around the front of the engine. Left alone the engine can overheat.

Cause

Audi bulletin 19-10-17 is a required vehicle update for "leakage at the coolant pump on Audi vehicles with V6 petrol engine built within a specific period". It applies to the 3.2 FSI V6 (engine codes CALA and CALB) in our A5 and Q5 manuals.

Fix

Ask an Audi dealer whether the Audi water pump update has been done on the car. If the pump leaks, replace it with the thermostat and connecting piece gaskets, as the A5 water pump assembly overview shows. Use the coolant Audi specifies, fill and bleed the system, and check for leaks with a pressure tester once warm.

Repair instructions on this site

Sources: Audi technical bulletin 19-10-17 (supersedes 19-10-15).

Audi air suspension: compressor failure on the A6 and Q7 (2005–2010)

Symptoms

The ride height can no longer be changed in the MMI, the car sits low, or the suspension warning lamp comes on with fault codes. Often the compressor runs for a long time, gets hot and then stops working altogether.

Cause

Audi bulletin 43-10-01 gives the cause as poor performance or failure of the air suspension compressor, so the system can't reach its target height. A slow leak in an air spring or line makes the compressor run longer and wears it out sooner. The bulletin also has the compressor relay (J403) checked, as a failed relay gives the same symptoms.

Fix

Read the fault memory and check the compressor relay first, as the bulletin describes. Then check the whole system for leaks before replacing the Audi air suspension compressor, or the new one will fail too. Bulletin 43-10-03 explains a common fault code. The Q7 air suspension uses a similar air supply unit and valve block.

Repair instructions on this site

Sources: Audi technical bulletins 43-10-01 and 43-10-03.

Audi ignition coil failure: 1.8T, 2.7T and 3.0 misfire (2001–2003)

Symptoms

Rough idling, loss of power and a flashing or steady engine light, with misfire codes stored. One cylinder usually goes first. It affects the 1.8T in the TT and A4, the 3.0 V6 in the A4 and A6, and the 2.7 biturbo in the A6 and Allroad.

Cause

These engines have a separate coil on each spark plug. Many coils fitted to 2001–2003 cars fail early. Audi ran a service campaign to replace all coils that were not at the latest production level, covering the 1.8-litre, 2.7-litre and 3.0-litre engines in the TT, A4 and A6.

Fix

Read the fault memory, then swap the suspect coil to another cylinder: if the misfire follows it, the coil is faulty. Check the spark plug at the same time. The Audi ignition coil campaign shows how to identify the old coils and specifies puller T40039, which stops the coil being damaged as it comes out. Replace any Audi coil pack of the old type with the current part, not old stock.

Repair instructions on this site

Sources: Audi service campaign, 2001–2003 model year vehicles: replace ignition coils.

Audi A3 TDI high pressure fuel pump failure: P0087, stalling and metal in the fuel (2010–2011)

Symptoms

The engine light comes on with P0087 (rail fuel pressure too low) or P0088 (too high). The engine clatters loudly, loses power, runs roughly or will not start, and can stall while driving. It affects the A3 2.0 TDI with the CBEA common-rail engine.

Cause

The high pressure fuel pump wears internally, and the wear debris contaminates the rest of the fuel system. NHTSA opened an investigation in 2010 after stalling complaints on 2009 Jetta TDIs, widened it to the A3 TDI as engineering analysis EA11-003, and closed it in 2015 with 713 complaints across 2009–2012 VW and Audi TDIs. Volkswagen blamed petrol in the diesel and began a campaign in May 2013 to fit misfuelling protection to the A3 TDI. Audi bulletin 01-11-18 covers the same symptoms.

Fix

Take a fuel sample and check the filter first. The Audi A3 TDI P0087 bulletin says rust or metal debris in the fuel system means a major component failure, and that further parts may need replacing so no debris remains. That can mean the injectors and lines as well as the A3 TDI high pressure fuel pump. The A3 shares its CBEA engine with the Jetta SportWagen TDI, so the 2.0 TDI fuel injector procedure in the VW manuals applies. Damage from fuel outside the US diesel standard is not covered by warranty.

Repair instructions on this site

Sources: NHTSA engineering analysis EA11-003 (opened from PE10-034), closing resume March 2015; Audi technical bulletin 01-11-18 (January 2011).