- My model of MX-5 is: 2015 MX5 ND1 2.0
- I’m based near: Hampshire
- I’m looking for technical help or recommendations on: Getting car to start
Hi,
As per the title my 2015 MX5 ND1 2.0 is not recognising the key fob despite recent Yuasa HSB053 battery install last week, yes it’s fully charged.
I’ve also recently changed key fob battery with Energizer CR2025 Battery.
Original battery died last month despite trickle charging with a CTEK trickle charger, battery showed as only 23% efficiency despite being fully charged.
I decided to buy a brand new battery, tested before fitting last week, but alas the same issue as before with red key fob warning light on the dash and start button coloured amber only. The key fob locks and unlocks fine and the infotainment system is working.
I’ve followed all the hints and tips on this thread ND not responding to keys - #13 by Countryboy. Tried disconnecting negative terminal for 30 mins and reconnecting. No alarm sounding at all.
My ND is kept under a half cover when parked, any ideas or solutions greatly appreciated.
Thanks,
Loz
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The BIG question. Before fitting it in the car, did you fully charge the brand-new battery so your CTEK was happy ?
Often new batteries have been sitting in a warehouse for months, and are only given a boost maybe twice a year - if they are lucky! Last two batteries I bought needed a full overnight charge before the smart charger was happy; while excellent batteries they were effectively empty of charge on delivery.
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Have you read the manual? Here MX-5_8EV5-EE-15E_Edition1.indb (mazda.media) The section 4-4 or Page 132. There are details of how to force a start when the key fob is not responding.
Do both keys refuse to start the car?
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Hi Loz. First off, the fob battery is a red herring - it’s only used to power the transmitter to lock/unlock the doors. What seems to have happened to yours is that it has ‘forgotten’ the embedded immobiliser chip in the key. When the door is opened, an antenna in the car ‘looks’ for a chip that it recognises; if it doesn’t find one, it won’t switch things on.
Do you only have one key? If you have another which does work, it’s fairly straightforward to clone the non-working one - I’m suspecting you haven’t though, so the next step is probably a recovery to a dealer reprogram the system.
Just as an afterthought - do you have more than one car key on your keyring? If so, take the Mazda key off and use it well away from any others. Sometimes after a power-down the system needs to see only one chip or it has a massive sulk!
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Hi Richard,
I checked the new battery with a gadget and it shows as 98% charged.
I did not trickle charge before fitting, if 98% isn’t a happy number please let me know and I will connect it to the CTEK.
Hi Mad Malc,
Thanks for the link for the info on the force engine start method.
I assume this would be just a temporary fix? It will at least allow me to access the OBD2 with an Autel scanner to check error codes.
I tried the spare fob, but now realise I need to add the immobiliser tag to test it out.
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Hi littleredrooster,
That’s an interesting explanation, many thanks.
Yes I do haave a spare key fob, when I tried it earlier, I forgot to add the immobiliser tag from the dodgy key fob, I will try it tomorrow.
I’m sure there is plenty of info on programming an ND key fob on here if I can get the spare to communicate, thanks.
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Could you explain what the ‘immobiliser tag’ is please as all standard NDs just have one fob that does everything. Do you have a none standard add on immobiliser? Just a bit confused now.
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My mmain key fob has a small metal rectangular tag on the keyring, I’ve made the assumption that it’s relevant which means I’m probably wrong. Is the immobiliser element built within the key fob?
The ND is stock, no after market alarm.
That tag has the key number on it if I am not mistaken. It is best to keep this in a safe place away from the car. It will have no relevance to your predicament.
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Hmm, please forgive me for being sceptical, but unless your gadget has nice short thick (eg 8mm) leads or prongs and can do a load test at a typical starting current, say 200 Amps, when making up its mind, as a matter of course I would always put the CTEK on a brand-new battery with its unknown state of charge. Only then I could be confident the battery was actually full.
The CTEK is not a trickle charger, but a Smart charger and it measures a number of different parameters in the battery whilst it does its business, and it will stop when the battery is full without ever risking any damage.
The longer it takes to charge the battery the more empty it was. Also naturally, a bigger capacity (Ampere-hours) battery takes longer to charge. For example; a 5 Amp CTEK will take at least 10 hours to charge a flat 50 Ah battery.
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I’ve got the spare fob working to unlock/lock.
Tried the forced engine starting method with both key fobs (not at the same time) no joy there.
I will take the new car battery out and hook it up to the CTEK and try again.
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You don’t have to take the battery out to charge it unless you can not get near a socket.
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I’m not admitting to anything here but a plonker of my acquaintance managed to put the replacement CR2032 battery in the wrong way round. It looked to be the right way but obviously wasn’t. Luckily the spare still started the car so I hotfooted it to the local dealer who corrected my error and simply said sometimes the contacts need a clean. When I replaced the battery in the spare fob I realised they meant my contact lenses and not the key fob.
Summary - flip one of the fob batteries over and try again.
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The battery in the keyfob has nothing to do with the immobiliser transponder. It is only used to power the transmitter to open/close the doors, as I explained earlier in this thread.
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I don’t know why or how, but my ND decided to recognise my keyfob and start for the first time in 3 months today!
New battery did not need recharging from install, same battery in remote, maybe the warmer weather has helped ?
