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Audi A6: Coil-on-plug ignition coil failure and misfire (1.8T 20v, 2.7T biturbo)

Coil-on-plug ignition coil failure and misfire (1.8T 20v, 2.7T biturbo) is a common electrical fault on the Audi A6 on the 2000–2004 cars, and we rate it major. Putting it right costs $250 to $1,200 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 34 documented faults on the Audi A6.

Vehicle
Audi A6
Only on
Bi-Turbo / twin-turbo
Engine
1.8L / 2.7L
Years
2000–2004
Fuel
petrol
System
Electrical

This page covers the Audi A6 as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Audi A6 faults34 documented faults on this model

What you are looking at

A four-cylinder ignition coil rail removed from an engine, beside a steel rule for scale.Example of the part — not this vehicle

A coil-on-plug ignition rail, removed. One coil per cylinder.

Cschirp · CC BY-SA 3.0 de · Wikimedia Commons

What goes wrong

The individual coil-on-plug ignition coils used on the 2000-on 1.8T and the 2.7T biturbo crack internally and fail, giving a flashing engine light, misfire and loss of power, often in damp weather. VW/Audi ran a large recall of early coils on 2001 to early 2003 cars, and a later Audi service action (J1) covered 2.7T coils in the A6 and allroad; those campaigns are long closed and many cars now run cheap aftermarket coils that fail again. A misfire left alone can overheat and damage the catalytic converter.

What you would notice

  • Flashing engine warning light
  • Engine shakes or stumbles at idle
  • Hesitation or loss of power under boost
  • Worse in wet or cold weather

How to check it

Where to look. On top of each spark plug under the engine cover on the 1.8T; on top of both cylinder heads on the 2.7T

Start the car from cold and watch the engine warning light: it should go out a few seconds after starting and must never flash. Let it idle and feel for shaking through the steering wheel and seat. On the test drive, accelerate firmly in third gear from low revs and feel for stumbles or jerking. Look at the tops of the coils with a phone torch for cracks or burn marks and ask what brand the coils are. If a workshop inspection is possible: read the misfire counters and stored fault codes with a scan tool.

Parts involved: Ignition coil.

What it costs to put right

$250 to $1,200 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

  • “Have the ignition coils been replaced, and were they genuine or OEM-quality?”
  • “Has the engine light ever flashed?”
  • “Was the coil recall or service action done on this car?”

Now check the Audi A6 you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

  • VWVortex: Audi recalls ignition coils (2001 to early 2003 VW/Audi coil recall)
  • AudiWorld: A6/S6 C5 platform, Coil pack recall thread
  • AudiWorld: allroad forum, A newly released coil pack recall (service action J1)
  • Honest John forum: Audi ignition coils again

Audi A6 buyer questions

Is coil-on-plug ignition coil failure and misfire (1.8t 20v, 2.7t biturbo) serious on a Audi A6?

We rate it major and common on the Audi A6. The individual coil-on-plug ignition coils used on the 2000-on 1.8T and the 2.7T biturbo crack internally and fail, giving a flashing engine light, misfire and loss of power, often in damp weather. VW/Audi ran a large recall of early coils on 2001 to early 2003 cars, and a later Audi service action (J1) covered 2.7T coils in the A6 and allroad; those campaigns are long closed and many cars now run cheap aftermarket coils that fail again. A misfire left alone can overheat and damage the catalytic converter.

How much does it cost to fix on a Audi A6?

$250 to $1,200 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Audi A6 years are affected?

Our research records this fault on the 2000–2004 Audi A6. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.

How do I check for it before I buy?

Start the car from cold and watch the engine warning light: it should go out a few seconds after starting and must never flash. Let it idle and feel for shaking through the steering wheel and seat. On the test drive, accelerate firmly in third gear from low revs and feel for stumbles or jerking. Look at the tops of the coils with a phone torch for cracks or burn marks and ask what brand the coils are. If a workshop inspection is possible: read the misfire counters and stored fault codes with a scan tool. Look here: On top of each spark plug under the engine cover on the 1.8T; on top of both cylinder heads on the 2.7T