Brake warning light on acceleration

[JJW]

1. My model of MX-5 is: __ND2 2022
2. I’m based near: __
3. I’m looking for technical help or recommendations on: __

I’ve noticed of late that under hard acceleration my brake warning light comes on briefly (as though the handbrake was on), but obviously the handbrake isn’t on!

Does anyone know why this is happening? The car is on 20k miles and due its 2nd service in May.
At the 1st service they said the front pads were roughly 50% so I presume they are getting thin by now, so I’m wondering why that’s the light is coming on, but it’s confusing why it’s on acceleration and not braking.
Brakes are operating normally and not making any noise.

[Wardy5]

The brake warning indicates more than just about handbrake application, although that’s often what people are most familiar with seeing.

On the NC this same issue is often connected with a low brake fluid level. Explained well by Mick here:

Handbrake. light

The brake fluid reservoir has the warning sensor in, the light doubles up as the handbrake warning light. It doesn’t have to go much below the full marker to trigger the light. Sometimes just cornering can trigger in when below the full mark. Also the brake reservoir doubles as the clutch fluid reservoir. Just to add, the caliper could be seizing and or slide pins, need a clean up and lube. Maintenance is the key, many posts about seizing brakes. A regular service (annual strip/clean/lube) not…

Cheers,
Steve

[JJW]

Ah thanks, that makes sense. If the pads are getting thin, as I think they are, the level could have dropped enough that the sensor could get triggered when it sloshes back on acceleration.

I’ll go and have a look at the level…

[PuffyPinkPanda]

I’m 6"1 and have noticed in spirited driving my leg bumps the handbrake sometimes, making the light go on.

Only needs millimetres of movement on the handle to make it light up, from what I can tell.

Im guessing the ND may have a similar thing.

[OrangeMX-5]

I had this on my ND2 only ever accelerating uphill and hardish left on a particular slip road to the M3, stopped doing it after service. Acceleration and curve at same time does suggest fluid moving could be the trigger.

[JJW]

Well I did think it was me at first - not by hitting it with my knee - I’m nowhere 6ft and my knee is nowhere near the handbrake.
I thought I hadn’t put it all the way down, but after checking, mine comes up something like an inch before the light comes on, so I ruled that out.

[JJW]

I’ve checked the reservoir and while the level looks well above minimum, it seems it’s low enough to trigger the sensor under certain conditions .

Almost time for the service so I’ll get it booked in sooner rather than later.

Thanks for all the replies.

[Patrick924]

Just had the same issue with my 2022 car, hard acceleration brought on the handbrake light for a few seconds then it went off.

Told the dealer about the fault and they suggested low fluid level

Car had it’s second service two weeks ago and the brake fluid was replaced and the issue hasn’t come back

The fluid level before was above minimum but lower than after the fluid was changed

[JJW]

Yes sounds exactly the same as my car. Did they change the brake pads?

[Patrick924]

Nothing changed, other than fluid. I dont have the paperwork to hand but seems to remember about 60% pad material left was on the report.

I changed my wheels over last weekend and put the summer ones back on and there was plenty of material left on the pads