MOT Advisory: Under Trays Fitted – What This Means

An MOT advisory notice we see appear particularly often on MOT history checks is regarding the fitment of under trays. It may appear on your MOT check as “Under Trays Fitted” or “Under-trays fitted obscuring some underside components”.

The vast majority of cars come with undertrays or under covers of some description as standard, so the question stands…

Why are under trays an advisory on an MOT?

It may seem like backwards logic having an under tray fitted advisory over the presence of a standard-fitting part, but the advisory notice here is generally not due to the presence of the under trays themselves.

In most cases the MOT tester is simply noting down that the fitment of under trays has slightly impeded their ability to test every aspect of your vehicle.

An MOT inspector isn’t going to remove parts and panels from your vehicle to perform a check. So if they believe that the under trays fitted to your vehicle could potentially be covering up something important, they’re going to make a note about it.

The easiest way to do this is with an official advisory note.

Ultimately it’s simply a case of an MOT tester covering their back. Imagine if your vehicle’s under trays were to fall off or become damaged. This may expose a hidden defect, perhaps brake line or chassis corrosion, that was invisible under the trays that your vehicle would then subsequently fail an MOT on.

Worse still, you may even have an accident due to deterioration of components hidden underneath under trays.

With this advisory note, the tester has declared that a full and thorough investigation may not have taken place, so they cannot be liable for not noticing a fault that may have been developing over time underneath the trays.

Your MOT tester would normally be knowledgeable enough to know if a fault may be developing under the trays and they will advise you in person if so. They may recommend having a full inspection undertaken during a routine service for peace of mind.

So although it’s a pain to see a vague advisory like this on your vehicle’s MOT history, at least you know that the fitment of the under trays themselves isn’t the cause of the advisory.

What is an under tray?

Your vehicle may have one or multiple under trays as standard equipment. Newer, modern vehicles almost always have under trays compared to older vehicles where they were not quite so ubiquitous.

It is a non-essential, non-structural vehicle component designed for engine noise reduction, aerodynamics/airflow, and minor underbody protection from dirt, water and road wear. They may span the entire underside of the vehicle, or just be fitted in key areas – underneath the engine being a main location.

Can you drive without an under tray?

It’s normally totally safe and legal to drive without an under tray fitted, but you may notice increased dirt and wear to your vehicle’s underside components.

Under trays are normally constructed from thin plastic or other lightweight composite materials and can be prone to damage and disintegration over time due to being so close to the ground. The screws/fasteners holding the under tray in place can often become damaged due to corrosion too.

This means it’s quite common to see loose or broken under trays on vehicles. It’s equally as common to see under trays on the side of the road having come detached from passing vehicles!

Interestingly, you can fail an MOT if your vehicle’s under trays are not properly secured or damaged – but your vehicle will not fail an MOT if it’s missing under trays altogether.