Audi A4: Ignition coil pack and ignition module failure causing misfires (1.8T 20v)
Ignition coil pack and ignition module failure causing misfires (1.8T 20v) is a very common electrical fault on the Audi A4 on the 1997–2001 cars, and we rate it major. Putting it right costs $250 to $1,000 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 45 documented faults on the Audi A4.
- Vehicle
- Audi A4
- Engine
- 1.8L
- Years
- 1997–2001
- Fuel
- petrol
- System
- Electrical
What you are looking at
Example of the part — not this vehicleA coil-on-plug ignition rail, removed. One coil per cylinder.
What goes wrong
The B5 1.8T uses an individual coil on each spark plug, and these coils fail at a high rate, especially on tuned cars; earlier AEB engines also have separate ignition control modules that can fail. A failed coil causes a misfire, a flashing engine light and a loss of power, and driving on a misfire can overheat and damage the catalytic converter. VW and Audi ran a coil recall in 2003 for 2001 to 2002 1.8T cars in North America; NZ and AU cars, many of them imports, were generally not covered and any campaign has long since ended.
What you would notice
- Flashing or steady engine warning light
- Rough, shaking idle
- Stumbling or jerking under boost
- Hesitation and loss of power
- Hard starting
How to check it
Where to look. Four coil packs on top of the engine under the plastic engine cover; separate ignition modules on earlier AEB engines
Start the engine and watch the dash: the engine light must go out and must never flash on the drive. 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: a jerk, stutter or flat spot under boost points to a coil or ignition module. Open the bonnet and look at the four coil packs on top of the engine for cracked tops, burn marks or mismatched brands. Ask whether the car has been tuned, as chipped cars eat coils. If a workshop inspection is possible: read fault codes for misfires (P0300 to P0304) with a scan tool, swap coils between cylinders to see if the misfire follows, and check the spark plugs and ignition modules.
What it costs to put right
$250 to $1,000 at New Zealand independent workshop rates. That is for this job on its own, not for the car.
Ask the seller
- “Have the coil packs been replaced, and with what brand?”
- “Has the car been chipped or tuned?”
- “Has the engine light ever come on or flashed?”
Now check the Audi A4 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.
Where this comes from
- vwtuning.co: The 7 Most Common Audi A4 B5 Engine Problems (ignition coil pack and ignition control module failure)
- TorqueCars: Most common 1.8T problems and issues (coil pack failure)
- VWVortex thread: Audi recalls ignition coils (2003 VW/Audi 1.8T coil recall)
- Edmunds forums: Audi A4 Ignition Coil Problems
Audi A4 buyer questions
Is ignition coil pack and ignition module failure causing misfires (1.8t 20v) serious on a Audi A4?
We rate it major and very common on the Audi A4. The B5 1.8T uses an individual coil on each spark plug, and these coils fail at a high rate, especially on tuned cars; earlier AEB engines also have separate ignition control modules that can fail. A failed coil causes a misfire, a flashing engine light and a loss of power, and driving on a misfire can overheat and damage the catalytic converter. VW and Audi ran a coil recall in 2003 for 2001 to 2002 1.8T cars in North America; NZ and AU cars, many of them imports, were generally not covered and any campaign has long since ended.
How much does it cost to fix on a Audi A4?
$250 to $1,000 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 A4 years are affected?
Our research records this fault on the 1997–2001 Audi A4. 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 engine and watch the dash: the engine light must go out and must never flash on the drive. 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: a jerk, stutter or flat spot under boost points to a coil or ignition module. Open the bonnet and look at the four coil packs on top of the engine for cracked tops, burn marks or mismatched brands. Ask whether the car has been tuned, as chipped cars eat coils. If a workshop inspection is possible: read fault codes for misfires (P0300 to P0304) with a scan tool, swap coils between cylinders to see if the misfire follows, and check the spark plugs and ignition modules. Look here: Four coil packs on top of the engine under the plastic engine cover; separate ignition modules on earlier AEB engines