I’m looking for technical help or recommendations on: immobilizer/ alarm issues - can’t turn off alarm or start car
Hi all,
A fairly recently new owner of a 2015 MK4 mx5 and first time on the forum!
Loving the car, it’s a lot of fun and everything I was after, but I’ve got my first niggle which I need some help with please!
I went to unlock the car the other day with the keyless entry and it failed to work. I tried pressing the button on the car several times and on both doors with no luck. The keys didn’t work either. I used the physical key to manually open the door which worked but set off the alarm which wouldn’t go off for 10 minutes. I then replaced the battery in the keys which allowed me to turn the alarm off.
Thinking it was just the low battery in the keys I went to open the car again the next day and experienced the same thing. I’ve changed both batteries in both sets of keys so I know it’s not that. I wondered if it could be car battery related but the alarm works with this disconnected, and the car was starting fine a couple of days before that.
My thoughts were the same - ensure the main car battery is fully charged and go from there. If that does solve things, consider investing in a battery conditioner/trickle charger to avoid issues in future.
Considering the odd codes a suspect battery can throw up I buy a new battery for any second-hand car I buy unless the current one has a receipt showing it’s been changed in the last couple of years.
Ok, it often a hundred quid, but it pretty fundamental to even the simple MX. It runs on software and a reliable/robust voltage provider is key.
A cheaper alternative is a free battery check at one of the big sheds. They have sophisticated kit so worth a go.
I’m suspect of the battery too as I don’t use the car daily and also given the time of year.
I’ve opened up the bonnet and popped the battery on charge. Still can’t get the alarm to stop going off though, it’s been going for the best part of 5 mins now which I’m sure the neighbours are loving
It doesn’t seem to be the battery as I’ve had that on charge all day and the voltage is good. I even tried disconnecting for a while then reconnecting.
Seems to be a fault somewhere. I did notice a couple of weeks ago on one of two occasions that the door button wasn’t working first time and seemed a bit intermittent. I’m not sure how the sensor/ immobiliser system within in the car tracks the key but it could perhaps be that that’s playing up?
I think water ingress is the next thing to check and is something I’d been suspect of.
The cars parked outside and not undercover and we’ve had some bad weather recently including around 3 inches of snow swallowing the car for several days.
I’ve also allowed it to get pretty dirty recently which could cause the same issue you experienced blocking the drain hole @Budersack
I’ll start with a good clean then investigate further.
