I’ve been a member of this forum for a few years but not many posts; I am a little more prolific on MX5Nutz but I am more of a watcher… no inuendos please
My little NB has been developed over the past few months into the potential track car it is going to be, problem being that upon stripping back some dodgy wiring under the dash I found this:
Now i’ve always thought it was weird that i needed two keys; one to get in and one to start.
I’ve owned this car over a year already and it’s not stolen, i bought it from an MX5Nutz member who has had many he just said there was a problem with the key.
What i want to know is:
Can i bypass this transponder as it’s plugged into the loom with a key DUCKTAPED to it 2. Can i remove the whole “key” assembly all-together and use a switch? This is a track car thats located in a locked garage thats behind a locked gate with a BIG dog.
The key is taped there so that whenever the ignition is turned on it picks up the chip information from within that key to enable the immobiliser to pass control to the ecu.
You need to leave it in place as car will not start without chip information.
There are neater ways of doing this and keys are very easy to clone on this car. Private message me if you would like to discuss.
Further issues to the fire here; when I bought the car it was fitted with a “keypad” attached to the windscreen and a black box under the dash; it was tied into everything.
I removed this; this is when I found the key! Would you say this was the “immobiliser” and if it isn’t can I just remove the immobiliser?
Sorry no clue what the keypad might be - please put up a photo as may ring a bell.
The immobiliser I speak of is the factory one on this car. Under the dash to the right of the steering column you will see a cigarette packet sized box marked NC30 or GE4T - this is the factory fitted immob box.
Not possible to bypass as far as I know - you have to work around this.
Sorry, realise I have assumed this is a MK2 not MK2.5. Same principles apply with MK2.5 just cannot clone transponder chips as rolling security ie. update stored data every time they are used.
Yes this is a MK2 and not MK2.5
I will try and find it; I chucked it in the garage. It was tied into everything; ignition, radio, battery, alarm horn etc
Sure it’s an NB and not an NBFL? When was the car first registered? Any car registered after Augst 2001 up to Early Spring 2005 will be NBFL’s (Mk2.5)
I have an NBFL (built late 2001) - first registered in Feb 2002. I have two keys, one with a plastic end (the key ring end) and the other a plain steel key. The plastic ended key is the one with the transponder, the plain steel key I’ve always understood to a ‘valet’ key (it says so in the owners handbook). The plastic ended key is both alarm set, and ignition key, the plain steel one does not - as far as I know, set or unset the alarm or start the engine either, it’s intended “as it says in the book” for use by a valeteer working on the car, it will lock and unlock the door and boot locks, that’s all.
I’m not sure why you need two keys, one to lock and unlock the doors, or another to start the car, not do I know why - as you describe - there’s another key taped to the transponder. Which key (of the three) is plastic ended one? If it’s the plastic ended one, then this is the normal door and ignition key, and the other two are, if all steel, valet keys. I can only assume an earlier owner strapped the transponder key onto the transponder itself, God - and he or she - know why. This would allow a valet key to start the car and set and unset the alarm (if fitted) at a guess, though I can’t swear this is true. You cannot fit a switch to overcome the transponder, it relies on sensing only.
I’d be interested to see Rhino’s comment on this one.
People get confused as to what can and cannot be done with these systems.
Not surprising really - I like to think I know them well but hardly a day goes by without something new learnt.
The basic rules are that paired immobiliser box and ecu communicate with via the transponder chip(s) coded to them. The ring around the key entry is the chip information pickup.
It should be possible to make any repair to these where necessary without changing any locks/ignition as these only rely on the physical metal key cut to code.
Not actually sure what has happened to the original posters car in the past but suspect there has been issue with the original ecu/immobiliser and the repair has been done but not in a very satisfactory way. I expect the keypad to be associated with an aftermarket alarm, totally separate to this issue although wired to ignition and possibly sounding via the horn.
Likely a dogs breakfast of a car, had a used steering lock fitted from one car, and a used ECU from another car. ECU replaced because? Fixed up for cheap, and probably corners cut elsewhere. Its a bodge. Hopefully, it was very very cheap.
Your steel key is not a valet key, a valet key had a grey plastic end instead of black. It will lock and unlock the doors and start the engine but not allow access to the boot, glove box or centre console. I think of the term valet being used in regard valet parking not a car valet. Your steel key is just a clone of your primary key without the immobiliser aspect.
