Car symptom checker · free · no signup
What's Wrong With My Car?
You don't need a fault code — or a registration — to start. Pick what the car is doing, answer a few quick questions, and see the most likely causes, ranked, with a clear verdict on whether to keep driving and what to do next. It works for any car on Irish roads, and speeds are given in km/h.
Free interactive diagnosis
What is your car doing?
How it works
Pick the symptom
Won't start, a warning light, smoke, poor running, a leak, the brakes, the steering or a noise.
Answer a couple of questions
Each one is chosen to split the possibilities apart — the same questions a mechanic asks at the counter.
Get the shortlist
The likely causes in order, how to tell them apart, a verdict on whether to keep driving, and what to do next.
Taking it to a garage
Tell them what you noticed, not what you think it is. “A knock from the front left over speed bumps, only at low speed” is more use to a mechanic than “I think it's the suspension”. The questions here are a good checklist for what to mention.
Ask for the fault codes. If a warning light is on, the stored code narrows the list far more than any questionnaire. Most garages will read it, and a basic OBD reader costs less than one diagnostic hour.
Check what's already been done. Before paying for a big job, it helps to know whether the part was replaced recently. The manufacturer's dealer service history shows what was actually replaced, when and at what mileage — for Irish-registered cars and imports alike.
Common questions
Is this a diagnosis? Can I rely on the verdict?
No. It's general information to help you understand a problem, not a diagnosis, an inspection or professional advice. We haven't seen the car, and the real cause may not be on the list. Have the car checked by a qualified mechanic before relying on it and follow their advice over ours — and if you're unsure whether it's safe, don't drive it. You use the tool at your own risk, and we can't accept responsibility for decisions made on the strength of it.
What do the green, amber and red verdicts mean?
Green means it's usually a nuisance rather than a danger — get it checked when convenient, and sooner if it gets worse. Amber means you can drive gently but should get it looked at within days. Red means stop: don't drive it until it's been checked, because carrying on risks the engine, the brakes or the steering, and recovery costs less than the damage. For a car that won't start, the verdict tells you whether to work through the simple checks first or stop trying and have it recovered.
Why can't I enter my registration?
There's no public Irish vehicle register we can look a car up in, so the checker works from your answers alone and ranks the causes for a typical car with those symptoms. That's the same shortlist a mechanic would give you over the counter — it just can't be tailored to one car's history.
Why does it ask whether my car is petrol or diesel?
Because the likely causes are completely different. A diesel that won't start on cold mornings is usually glow plugs; a petrol one is usually fuel or ignition.
Should I still get the fault codes read?
Yes, if there's a warning light. A fault code narrows the list further than any question can, and most garages or a cheap OBD code reader will read it.
Does it cost anything?
No. The checker is free. The paid product on this site is a different thing: the manufacturer's own dealer service records for a car, found by its VIN, which show what was actually replaced and when. That costs €12.99, and nothing is charged if no records are found.