/ Motoring

Warning lights on? Your car will fail its MOT test

Car warning lights

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?

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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.