Intermittent Spare Key starting problem on NC2 - Flashing Red Padlock - then its ok again?

Technical Area Electrics & ICE
1

I have a 2010 NC2 - with an aftermarket spare key fob, which has been functioning perfectly, until now. The inners of the aftermarket spare are different from the standard key in as much as there is a printed circuit board with a CR2032 (not the same as the original key) battery, and this comes out in one piece with the battery still attached.

I have changed the batteries in the fob, it unlocks and locks fine, but every now and again, it will not start the engine, and the padlock icon on the dash will just flash as I twist the starter all the way. As soon as I use the original key, the car fires right up. And then I try the dodgy one again and all of a sudden it seems to be fine again, just like it always used to be. WTH??

I understand that there is a tiny transponder hidden in there somewhere apart from the board that does the doors, and I am wondering if these transponders go bad, or need to point in a certain direction to work (there is a little rattle in there, so I suppose it could be floating around just a little, but I can’t for the life of me get to it even having remove the 3 screws, I just don’t want to break the housing.

Do transformers go bad or ever need reprogramming. Has anyone had a similar issue? - While it is no biggie as I have the original key, I can’t really trust the spare anymore and feel like I need to sort it out, just in case one day I need it.

OCD - yes I know!

Thanks,

Richard.

2

Sometimes the tangs connecting the battery just need a little fettling for better contact. Whether what I’ve said has any relation to the transponder who knows but worth a try.

3

Thanks, I just went to the locksmith and got another simple key and transponder made up to go with it, just in case, works perfectly. Job done!

4

There is some confusion here. The battery powered part of the key operates the remote opening but has absolutely no affect on (or part in) the car’s immobiliser. The key blade section contains the coded chip which the car ‘reads’ via a coil in the ignition barrel and which allows the car to start. The car’s electrical system performs this function. That is the system which is giving the problem with the flashing ‘key’ icon. This chip is not in the other part of the key, nor is it powered in any way by the battery in the key. You can remove the key blade from the key and it will still start the car.
JS

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