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Micra 1.0L Immobiliser Query

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DTS

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Jun 17, 2010, 4:07:11 AM6/17/10
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Hello
Thanks for any advice in advance
Car is a Nissan Micra 1.0 litre 1999 on an S reg used as a cheap
runabout.
I got in the car last Friday and tried to start the car and the car
started for 2 seconds then stopped with the check engine light
flashing on the dash which after digging round the internet discovered
it was a NATS problem. After repeated retries I gave up and tried the
other key with the same problem.
I called my Auto-Electrician guy who took a look and promptly
discovered the immobiliser had lost its codes for the keys. He
reprogrammed it with the key codes and we were back in business.
The electrician also checked all fuses and relays and said they were
sound and couldn’t see a problem with rusty fuses that sometimes
causes problems with the NATS according to him
He was unsure as to why the immobiliser lost the key codes and I’m a
bit wary now and question if it could happen again.
Fortunately this time it was on the driveway but what about if it
happens again!
Can anyone explain why this would have happened ?
The only thing that has been done recently is the battery was changed
in March but this is 3 monthes ago surely that cant have affected
it ???

Hope someone can shed light on this or has come across something like
this before?

Damian

Mrcheerful

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Jun 17, 2010, 4:15:34 AM6/17/10
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strong electric/mahnetic fields can mess up immobilisers on anything, which
is why I don't put my phone in the same pocket as keys. On yours you can
re-program the keys for yourself if it happens again. which type of system
have you got? separate key fob or buttons in the key?


DTS

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Jun 17, 2010, 4:28:50 AM6/17/10
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> have you got?  separate key fob or buttons in the key?- Hide quoted text -
>
> - Show quoted text -

Thanks for your reply
The only keys i have black NATS ones with a red chip in them as its
the pikey version of the car.
He recoded it using a plug in coding device and also said Nissan would
have charged a packet to do the same thing.
It only cost me 60 Quid to have them reset .
Could a microwave cause the keys to screw up ????

Paul - xxx

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Jun 17, 2010, 4:40:41 AM6/17/10
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DTS wrote:

Cured the same thing on our lasses Micra by charging the battery fully
... ;)

CTEK make great chargers, brings dead ones back to life!
http://www.ctekchargers.co.uk/

--
Paul - xxx

'96/'97 Landrover Discovery 300 Tdi
Dyna Tech Cro-Mo comp

DTS

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Jun 17, 2010, 4:55:44 AM6/17/10
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> CTEK make great chargers, brings dead ones back to life!http://www.ctekchargers.co.uk/

>
> --
> Paul - xxx
>
> '96/'97 Landrover Discovery 300 Tdi
> Dyna Tech Cro-Mo comp- Hide quoted text -

>
> - Show quoted text -

Do you think replacing the battery would have caused the immobiliser
fault to start with ?

Paul - xxx

unread,
Jun 17, 2010, 5:32:36 AM6/17/10
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DTS wrote:

Probably not ... but it could be that the new battery might have been
'on the shelf' for a while and not been up to full capacity. Throw in
a few short journeys with little to no charge being added (certainly in
my wifes case) and the battery is draining rather than charging.

Worth trying a full charge anyway, the least it will do is confirm the
battery is OK or not.

Might also be worth checking the earth lead. Could be that it's been
disturbed during the battery changeover.

DTS

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Jun 17, 2010, 5:59:16 AM6/17/10
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Ill look at the battery voltage and give it a good charge over the
weekend but am a bit worried about disconnecting the battery again in
case the immob kicks in .
Does this sound like the immobiliser unit is a bit ropey ???

Duncan Wood

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Jun 17, 2010, 6:55:53 AM6/17/10
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On Thu, 17 Jun 2010 10:59:16 +0100, DTS <damian.t...@googlemail.com>
wrote:

Unless you're going to charge it with a really big charger then don't
disconnect it.

DTS

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Jun 17, 2010, 9:23:24 AM6/17/10
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On Jun 17, 11:55 am, "Duncan Wood" <nntpn...@dmx512.co.uk> wrote:
> On Thu, 17 Jun 2010 10:59:16 +0100, DTS <damian.tomlin...@googlemail.com>  
> disconnect it.- Hide quoted text -

>
> - Show quoted text -

Thanks for your advice much appreciated.
Im still not 100 convinced the immob is ok but i will have to wait and
see

Tim Downie

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Jun 17, 2010, 12:46:42 PM6/17/10
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As I understand it, the memory in the key is non-volatile, it's just an RFID
chip. It is the car that has to be taught to recognise and accept the key
as being the right key. If your old key still works I think you can forget
any microwave/mobile phone damage to your key.

I would have thought though that the immobiliser system in the car would
also have non-volatile memory as otherwise every Nissan owner in the country
would have to be getting their systems reprogrammed every time they had a
flat battery so I'm not convinced that the battery is at fault either. You
didn't have a problem when the battery was changed which would support the
"non-volatile" memory theory.

This doesn't help you alas. It's possible I suppose that the immobiliser's
memory might not be entirely non-volatile, i.e., it might lose its memory if
it loses power for a long time. I suppose this could occur if the
immobilser's power supply or earth was faulty.

Lastly, RF interference can sometimes cause a temporary loss of function
(although not usually wipe an immobiliser system's memory). Got any
neighbours with new aerials (CB) or a taxi driver living next door?

Tim

bill

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Jun 17, 2010, 4:45:53 PM6/17/10
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DTS <damian.t...@googlemail.com> wrote:


Wife's Micra had a very similar sounding problem. Sometimes had
problem starting but after leaving it for a minute or so would
eventually start and run fine.

Slowly got worse but would start eventually. Then after a year or so
it started cutting out on the road. Felt like fuel running out, so I
blamed the fuel pump but tests showed that this was fine. Changed the
fuel filter - no change. Next to get the blame was the temperature
sensor because after unplugging this and plugging it back in it
started behaving. I changed the connector and all was fine for a few
months until the problem came back worse than ever. Unfortunately,
each time it was taken to the garage it performed fine and there were
never any fault codes on several checks. Main dealer was stumped and
was suggesting a new ECU for around a grand!

Independent mechanic was also stumped but suggested the crank sensor
on the grounds that unplugging it gave the same symptoms. Changed the
crank sensor and all was ok again for about 9 months. Back came the
problem. Started looking around the internet for a replacement ECU.
Found one on eBay were the owner said main dealer insisted it was the
problem so he changed it only to have the problem return. He traced
the problem to a relay and was therefore selling his working ECU. I
emailed him and asked which relay. He very kindly told me.

Pulled said relay from Wife's car and tested it in my lab at work. I
discovered that every now and then on operating the relay the
contacts, whilst clicking and closing (ie it appeared to be working)
showed a resistance of a few hundred ohms. Found the problem!!

This relay is in the relay box beside the battery. It is the
immobiliser relay which supplies the injectors. There are two blue
relays near the front of the box. One is the immobiliser the other is
the radiator fan control. I cannot remember which is which. I swapped
them over and ordered a new relay. In the meantime the car would now
start instantly on turning the key. New relay arrived and I fitted it
and have not had a single problem since. It was autumn and the car
was used as a run around so I wasn't too worried about overheating
with the dodgy relay contolling the fan for a couple of days until the
new one arrived, just kept an eye on the temperature guage but didn't
have a problem.

This was more than a year ago so I am convinced that it is now fixed.

Definitely worth checking this relay especially if there are no fault
codes to read.

Bill

DavidR

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Jun 18, 2010, 12:09:54 PM6/18/10
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"DTS" <damian.t...@googlemail.com> wrote in message

> The only keys i have black NATS ones with a red chip in them as its
> the pikey version of the car.
> He recoded it using a plug in coding device and also said Nissan would
> have charged a packet to do the same thing.
> It only cost me 60 Quid to have them reset .
> Could a microwave cause the keys to screw up ????

As another poster said, it's not the keys getting messed up; it's the car
that forgets. My Primera also had central locking, which had a separate
blipper which the car ignored on a few occasions. It never forgot the
ignition code though. For the CL there is a simple sequence involving the
ignition key, door switch and fob - no tools or plug in computery stuff
required. Maybe the key is similar.

I got the magic spell for the CL from alt.autos.nissan; perhaps the ignition
sequence is also known.

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