Active Bonnet issue?


On Tuesday evening while I was driving along a wheel trim of another hit the front of my MX-5 ND. Usually the only concern I would have would be around damage to the front paintwork (which there was but only a small scratch) but on this occasion it activated the ‘active bonnet’ feature on my car. Obviously this was a massive surprise to me which then developed into a great concern. 

Upon contacting Mazda Assistance, they informed me that the system is a one time use and has to be recovered to a dealership for it to be reset. This was much to my frustration as it was 6.45pm and the dealership was closed so it was taken into storage overnight. Now, you may think this is no real issue, minor inconvenience but no biggie. Yet this is where the issue arises, upon further inspection of my bonnet it seems that the mechanism (I think hydraulic rods) of the ‘active bonnet’ has in fact dented/creased my bonnet where the rods have impacted the bonnet to raise it.

For the past 2 days I have been trying to get an update on my car and its status. I was told that it was taken to Sandicliffe Mazda in Nottingham, yet when I called they said they had sent it to Mazda in Stapleford as it needed body repair (the bonnet). Yet when I called Stapleford Mazda they said they had no paperwork or vehicle. So then I phone Sandicliffe back only to be told that I need to speak to Mazda Assistance. When I got in touch with Mazda Assistance they first told me it was at Sandicliffe for which I informed them it wasn’t. After a few minutes on hold they then informed me that its been taken to an accident repair shop in Derby for quotation (today). I asked Mazda Assistance who is going to pay for the repair bill for which they said it was probably going to be me but I need to call Customer Relation Enquiries tomorrow to find out, bearing in mind tomorrow they would’ve had my car almost 3 days.

Now, am I being unreasonable to think that because the damage to the bonnet was caused by the ‘active bonnet’ mechanism that Mazda should be covering this cost as the car is still under warranty? Could I highlight that there is a design flaw/fault if the mechanism actually creates further damage to the car? Or are Mazda Assistance correct in their assumption that because an object hit/collided with my vehicle it triggered the ‘active bonnet’ mechanism so I am therefore responsible for paying for the repairs akin to a standard collision with a vehicle etc?

Any thoughts and comments would be great appreciated.

Many Thanks, J   

I don’t know the answer regarding liability but have read of several instances of this happening now to people hitting animals on the road with little damage apart from the activation of the bonnet which itself seems to be the expensive bit to get fixed!  Keep us posted… 

Unless it has activated when it should not have, then It will probably be ‘accident damage’ and therefore down to you (or your insurers as it will not be cheap). 

The dealer talk of a ‘reset’ sounds as if they are unfamiliar with it.  AFAIK it’s activated by pyrotechnics and almost bound to damage the bonnet.  Parts will need to be replaced.

When Jaguar XF’s started using active bonnets, raised by airbags I believe, the repair costs came as a shock to owners - £3,000 rings a bell, but it might have been more.

Sounds like an insurance claim then.

Will interesting to hear their side though, bet they refute the claim. 

So how can I de-activate the damned thing?

That is just what I was thinking, I know on the Mk3.75 there are two sensors bolted onto the fog light brackets behind the front bumper I know this because I almost removed one when I removed my light surrounds to spray them gloss black but realised it could be an impact sensor for the bonnet so bolted it back up carefully.


 surprised a plastic wheel trim was enough to set it off


Not as surprised as me 


Excuse my ignorance but not heard of this before. What is the purpose of this feature?

Pardon my ignorance but never heard of this before. What is the purpose of the feature?

Copied from an Australian entry in a forum dated March 2016:

"I have a 9 month old ND GT - MX5, which I love. I was driving recently in the Australian countryside, when I stopped at a service station. On entering the driveway, the ABS (active bonnet system) explosively deployed. I did not hit anything, nor go over a bump. The airbags did not go off, and there was no visible damage to anything other than the bonnet and of course the struts that deployed.

Mazda have been really helpful; they are giving me a new car, and a hire car from the day of the incident to use until the replacement happens. They paid all towing and taxi fares from the accident site to my dealership and home (we are talking 100+ kms taxi ($A375), and about $A500 towing).

The repair shop said they had heard of one other such incident, but no known details are available. The repair cost if this happened to me as a civilian would have been around $35,000! I saw the car the other day after they had removed the broken bits. It has long since stopped looking like a sports car, and looks more like a yard sale."

Note: £1 = about A$1.70
So A$35,000 = £20,500


It raises the bonnet at the hinge end so that if you hit a pedestrian the bonnet can deflect and absorb some of the impact hopefully reducing injury.


Without this the bonnet is very close to the engine and cannot deflect much before it touches the solid heavy cylinder head and cam cover etc.

Can anyone tell me from what date UK cars had this feature, and how else could I determine if my car has it?

Was introduced with the mk3.75 nc3, standard feature since then

I think the others are correct & it will be down to you. Also correct above that the idea being if you hit a pedestrian they will slide up the bonnet & to the roof instead of impacting into the windscreen. Jaguar have been using this idea for some time now. If you disconnect the system & have a crash you could be liable to no end of trouble/lawsuits.

Many electrical problems are traced to connectors that have come loose. It would be interesting to know if there are any connectors which if they were to become disconnected would cause the active bonnet system to fail to operate. If somebody could highlight these connectors then it would allow owners to check that these connectors are properly connected on their cars.

Loved the ND as soon as it came out. Hoop rubbing was a bit of a concern, gearbox failures was worrying, now this.

Sticking with my NC Mk 3.00 is looking more like the better option.

From the ROSPA website on active bonnets.

A sensor array along the front of the car detects if the object struck is a pedestrian to prevent the system from deploying by mistake. If the sensors calculate that protection can be offered, then the bonnet will deploy.

Shouldn’t activate unless the sensors detect it is a pedestrian that has been hit. The sensors system is either faulty or as the sale of goods act would describe it ‘not of satisfactory quality’. Would be interesting to know if the handbook says something similar to ROSPA.

I would say you were extremely unlucky for a wheel trim to simulate a human body and cause the active bonnet to operate.

Can only guess that is struck one of the sensors directly.

Because of the potential danger and problems of this sort of system going off in the wrong circumstances, I thought it would be rather more intelligent in determining whether to deploy or in this case not. If a plastic wheel trim could cause this then presumably a well placed horse chestnut or even sizeable stone chipping could do the same.

Assuming the wheel trim damage is visibly small I would expect Mazda to cover this. The system should not have deployed. The fact it did could have caused you to have an accident.