P0300 on Audi: Causes, Symptoms and Fix Cost
Quick Answer
Not safe to drive
P0300 on a Audi means the engine computer has detected misfires across several cylinders without being able to pin them to one specific cylinder, so it flags the whole engine rather than a single cylinder. The most common trigger is worn or fouled spark plugs that no longer spark reliably, and a full set costs about 60 to 230 EUR fitted. A steady light is a warning, but a flashing light means raw fuel is reaching the catalytic converter, so stop driving. VW, Audi, Skoda and SEAT apps often show this code as P030000; the last two digits are a failure-type byte.
- Severity
- High · Misfire
- Typical repair cost, all makes
- €60-€700
Connect a standard OBD2 adapter (Bluetooth LE on iPhone) to your Audi and Skanyx tells you what P0300 means on that engine, whether it is safe to keep driving, and what the fix should cost. Free on iPhone and Android.
Get Skanyx freeWhat does P0300 mean on a Audi?
The Quick Answer above is the generic definition. What follows is the model-specific detail for the Audi models that log P0300.
Audi A4
2008-2024
The A4 shares the EA888 family with the Golf, so intake-valve carbon on direct-injection 2.0 TFSI engines is a leading misfire cause and responds to walnut blasting. Ignition coils are a frequent failure item and are usually replaced as a full set of four. On older 2.0 TFSI units, oil consumption from worn rings can foul plugs and bring on P0300 over time.
What causes P0300 on a Audi?
Beyond the generic causes listed on the main P0300 page, these are the patterns noted for Audi models:
Intake-valve carbon on direct-injection 2.0 TFSI engines
: Audi A4
Coil pack failures, typically replaced as a full set
: Audi A4
Plug fouling from high oil consumption on early 2.0 TFSI units
: Audi A4
How to diagnose P0300 on a Audi with OBD2
- Scan for companion codes (P0301 to P0312). If a cylinder-specific code is also stored, start with that cylinder before treating P0300 as a whole-engine fault
- Inspect the spark plugs for wear, oil or carbon fouling, and a worn electrode gap. Replace the full set if they are past the maker's service interval or if several look fouled
- Test the ignition coils, swapping one coil to a different cylinder to see if the misfire follows it, or measuring resistance with a multimeter against spec
- Smoke-test the intake for vacuum leaks, or spray carb cleaner around the intake manifold gasket and hoses and listen for an idle change
- Check fuel pressure with a gauge. It should hold steady at the maker's spec, typically around 2.8-4.1 bar (40-60 psi) on port-injection engines, and not drop under load
- Inspect the EGR valve for sticking and check intake valves for carbon on direct-injection engines, then run a compression or leak-down test if everything else checks out
How much does P0300 cost to fix on a Audi? (EUR)
Estimated repair costs for P0300 in EUR, compiled across makes. Expect Audi parts and labour towards the upper end of each range.
| Repair | Parts Cost | Labor Cost | Total Estimate | DIY Difficulty |
|---|---|---|---|---|
| Replace spark plugs (full set) | €20–€80 | €40–€150 | €60–€230 | Easy |
| Replace ignition coil(s) | €30–€200 | €40–€120 | €70–€320 | Moderate |
| Fix vacuum leak | €10–€80 | €60–€200 | €70–€280 | Moderate |
| Replace fuel injectors | €100–€400 | €100–€300 | €200–€700 | Professional |
Prices estimated as of October 2026. Costs vary by region, vehicle, and shop.
Codes related to P0300
These codes are often seen alongside P0300 or point to related issues, on any make:
Looking for the full P0300 reference (all makes, full diagnosis flow, complete repair cost matrix)? See the main P0300 guide