/ Motoring

Warning lights on? Your car will fail its MOT test

New tougher MOT rules will require your car dashboard’s warning lights to be working. If they don’t, your car will fail its MOT test. Is this a much needed safety improvement or a route to more rip offs?

The MOT test now includes a ‘Malfunction Indicator Lamp’ check. This requires the examiner to visually check that warning lights for electronic stability control, safety restraint systems, anti-lock braking systems and tyre pressure monitoring systems are not permanently illuminated.

The requirement came into effect on 1 January to comply with a revised European testing directive. It will be highlighted as an ‘advisory’ item only until 31 March, but from 1 April onwards, vehicles will fail an MOT if these lights are illuminated.

It’s just a visual check – so doesn’t require any diagnostic equipment to evaluate the actual cause of the light being on, but you can bet your bottom dollar the garage will charge you to investigate why a light is on (it will scan the system for a fault code, pointing to the cause).

The risk of rogue warning lights

When I recently asked my Renault dealer to investigate a warning light, the first thing they said was that there would be a £45 charge for a diagnostic check, then additional rectification costs depending on what that revealed.

My ‘fault’ was a service warning to check the handbrake (not covered by the new MOT rules as far as I can tell) which came on after the battery was disconnected.

As an ex-mechanic, I checked the physical components of the handbrake and there wasn’t an actual handbrake fault. In my view, it was simply a rogue indication because of the loss of power to the system. But to find that out for sure, I have to stump up £45, without even thinking of any consequential costs.

Don’t get me wrong, I completely agree that these lights are important – and if functioning correctly, they can let you know of a genuine safety risk.

So it seems sensible to make these an advisory notice. But, to me, the idea that they constitute an automatic MOT failure (without a proper investigation) leaves motorists open to being charged extra, perhaps simply because modern electronic systems are still too quirky and can display rogue signals from time to time. Would your car pass these new MOT rules?


I did rather sourly reflect on the irony that an apparent glitch in the instrument cluster of my VWAG car temporarily rendered it unable to display the status of some warning systems, and this included the ABS warning light. Rather inconveniently, I could not start the car until I interrupted battery power for an hour. Meanwhile, the system was smart enough that the ABS knew it was unable to report it’s Good Status to the instrument cluster, so logged a fault in the ABS that then shows as a latched ABS fault when the instrument cluster got over it’s glitch. So it wasn’t a real fault at all, but the ABS warning light was latched and the car would have failed an MOT. Time and expense later, I located a friendly vagcom guy who sorted out clearing the latched fault, confirming it was the instrument cluster dropping the ball, and not in any way attributable to the condition of the ABS,
Better (more resilient) system design, please.

g boulton says:
6 January 2017

just had mot on my proton,failed purely for hazard warning switch not flashing when switched on.Spoken to numerous people in the trade and its 50/50 wether this is a requirement as long as lights are flashing and it shows them flashing on the dash,


My car also failed on this a few years ago. The switch replacement was pretty cheap.

Bobbydoc says:
11 February 2017

I have an amber power steering malfunction light on my dash, but the power steering works fine with no problems. It cost me £2500. and eight weeks without a car to have it fixed, the diagnostics came up with a body error code. A specialist stripped down the steering and wiring, downloaded a new updated E C U and B M U programme from Ford USA, TWICE! fitted various electronic sensors and switches. But the Amber light is still on. The Garage got fed up of looking at it and said to me there in no fault but the light won’t go off!
So a £80000. Car when I bought it, only passed its MOT because it has flumexed the specialist, who passed the MOT for me. The light came on in December 2015 and it is still on now,but the power steering still works without any problems.

Julie mcgrann says:
21 December 2017

Our Vauxhall Meriva dashboard showed 3 different codes. One was a rear light. The garage said they’d changed the bulb and when we drove off the code was still up as faulty. As well as the other two codes. One of which was another light, even though that also was working perfectly.

We had taken the car in because the power steering sounded odd, crunchy, this wasn’t a fault listed on the dashboard fault lights though!
They fixed the power steering pipe at £150 total and said it would need to have a diagnostic evaluation for the warning lights which he couldn’t do.

We had a diagnostic evaluation that cost £35 and left the car to have the “necessary” repairs!
That cost us £195
This garage told us the fault indicator light that showed the airbag light fault would have to be done at a Vauxhall garage!
As we drove off the car still showed the 3 faults on the dashboard! One of which was still the rear light, even though it was working.

This led me to believe there is a malfunction with the fault finding system! Showing rogue signals!

What can be done?

Susan says:
30 March 2018

My Toyota auris just failed its mot just because 1 of my indicator lights on dash didn’t light up. Surely that can’t be a fail. All exterior lights working fine.


Regulations are regulations rules are rules laws are laws and MUST be followed or you face the consequences Susan If no one broke laws rules etc. there would have been no need for them to be made


Susan – If one of the malfunction indicator lights does not work when tested (for a short period after you turn on the ignition) it would not warn you of a potentially dangerous problem such as a fault with the braking system.