A car being prepared for its NCT test at the Alan Dawson Autoworks workshop in Navan

How to pass the NCT
first time.

Most NCT failures are not big mechanical faults. They are small things that were visible weeks earlier and never got looked at. Here is what actually catches people out, and what you can check yourself before you go.

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Written by the workshop at Alan Dawson Autoworks & Recovery · Updated 31 July 2026

The ten-minute check you can do at home

Do this in your driveway the weekend before your test. It costs nothing and it catches the majority of the avoidable failures.

Walk around every light Headlights on dip and full, sidelights, indicators front and back, hazards, brake lights, reverse light, fog lights and the number plate light. Get someone to press the brake while you look, or reverse up to a window at dusk and watch the reflection.
Check tyre tread and pressure The legal minimum is 1.6mm across the centre three quarters of the tread, all the way round. A 20c coin edge is a rough guide. Check the spare too, and look for cuts, bulges or uneven wear that points at alignment.
Test the wipers and washers Torn or smearing blades fail. So does an empty washer bottle or a jet that does not reach the screen. Both are a few euro and five minutes.
Look at the windscreen Chips or cracks in the driver’s line of sight are a fail. A chip repaired early is far cheaper than a screen.
Sit in and check the basics Every seatbelt latches and retracts, the horn works, the handbrake holds on a slope, the mirrors are intact and the boot and doors open and close properly from inside and out.
Note any warning light Engine management, ABS, airbag and brake warning lights on the dash are failures in their own right. If one is lit, get it read before the test rather than hoping.
Clean the car, inside and out Not vanity. A tester can refuse a car that is too dirty to inspect properly, and clearing the boot means the spare and the jack can actually be seen.

What are the most common reasons cars fail the NCT?

Lighting and electrical faults, tyre condition, and issues found underneath around suspension, steering and brakes. Between them these account for the bulk of failures, and the first two are things an owner can check without tools.

Lighting is the single easiest category to fix and the one people most often skip, because a blown bulb at the back is invisible from the driver’s seat. Tyres are next, and worn tread is usually a symptom rather than the cause: uneven wear across one edge normally means the alignment needs doing.

The categories you cannot self-check are the ones under the car. Ball joints, bushes, drop links, brake pipes and exhaust mounts all wear gradually, and a tester with the car in the air will spot play that never shows up while you are driving.

That is exactly what a pre-NCT check is for. The car goes on the lift, the same points get inspected, and you get a list with prices before the real test rather than a fail sheet after it.

Does a warning light on the dash mean an automatic NCT fail?

Several do. An illuminated engine management, ABS, airbag or brake system warning light is a failure item in its own right, regardless of how the car drives. Clearing the code without fixing the fault will not help, because it comes back.

Testers check that the warning lamps light on ignition and then go out, which is how the system proves it is working. A bulb that has been removed to hide a fault reads as a failure too.

The right order is to have the code read first so you know whether it is a sensor worth twenty euro or something structural. We read fault codes on the latest Launch diagnostic equipment, which covers the engine, ABS and the other systems the test looks at, so the answer is a diagnosis rather than a guess.

Is a pre-NCT check worth paying for?

It is if the car is more than a few years old or you do not know its recent history. It costs less than a retest plus the fixes done in a hurry, and it turns test day from a gamble into a formality.

The value is not the inspection, it is the timing. Finding a worn drop link three weeks before the test means a cheap part fitted at a normal price. Finding it on the fail sheet means a rushed repair and a second trip to the test centre.

A pre-NCT check also tells you what is coming. Brakes at 40 per cent are not a failure today, but knowing about them lets you plan the spend instead of being surprised by it. Many customers pair it with a full service so the car is only off the road once.

What do you need to bring on the day?

Your NCT appointment letter or email, your vehicle registration certificate or logbook, and photo identification. Turn up on time with at least a quarter tank of fuel and the boot cleared.

Missing paperwork is a wasted appointment, and appointments are not always easy to rebook quickly. Check the letter for anything specific to your vehicle before you set off.

Practical bits people forget: the car needs enough fuel for the emissions test, the boot needs to be empty enough to reach the spare, and if you have a locking wheel nut the key needs to be in the car.

Common questions.

How long before my NCT should I get a pre-NCT check?

Two to three weeks is ideal. That leaves time to order parts and get any work done at a normal pace rather than an emergency one, and still have the car back well before the appointment.

What tread depth do tyres need for the NCT in Ireland?

The legal minimum is 1.6mm across the central three quarters of the tread and around the whole circumference. Any tyre below that fails, and so does one with a cut, bulge or exposed cord regardless of tread.

Will a small windscreen chip fail the NCT?

It depends on size and position. Damage in the driver’s critical line of sight fails at a much smaller size than damage at the edge of the screen. If in doubt, get it repaired: a chip repair is a fraction of the cost of a screen.

Can you do the repairs if my car fails?

Yes. We handle the mechanical work a fail sheet typically lists, brakes, suspension, steering, exhausts, lighting and tyres, on all makes and models. You get the price agreed before any work starts.

Do you do pre-NCT checks on vans as well?

Commercial vehicles take the DOE/CVRT test rather than the NCT, and we prepare for that too. See our DOE and CVRT page for what that inspection covers.

Need it looked at properly?

Tell us the symptoms and we will give you a straight answer, a clear price and a slot that suits.

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