C5 Imobliser

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MaxPrimal
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C5 Imobliser

Post by MaxPrimal »

Hi Guys.

Went to start my car tonight and it would not fire. Well it was trying to start but not starting, like something was holding it back or not letting the engine fire and kick into life. I noticed at one point the centre screen flash up a warning which read something like "Electronic Anti-Theft System Fault". After a few more attempts and taking the key out / locking/unlocking the car - I did manage to get it to start and it seems (he says touching wood as he writes this) to be okay now.

I am assuming for some reason the car could not read the code off the key and therefore would not disable the immobiliser in the car - and this caused the issue. Could it be the battery in the key fob is going flat and this may have caused an issue or is the immobiliser function not related to the battery powered central locking in the sense the car provides all the power for this?

Just wondering if it is worth me changing the battery (and if so does anyone know what it takes?) or if this could be a sign of something worse. Never had this issue before and typically it does it as I went to take my car round to my brothers for the night as I am taking him and his family to Heathrow at 5am tomorrow in it!

Anything anyone can suggest would be great tonight as I will go mental if the car plays up tomorrow!

Thanks
Max
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Re: C5 Imobliser

Post by myglaren »

Can you get the battery charged up fully - trickle charge for at least 24 hours.
It may just be down a bit if you have dome a lot of shortish trips with lights and heaters going in the cold and dark.
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MaxPrimal
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Re: C5 Imobliser

Post by MaxPrimal »

Well I drive to work each day - 15 miles each way with a stop in the middle to take/pickup my daughter on the way. Heaters are on full heat, half power most of the time. Side lights are on most of the time.

Sorry I am talking about the battery in the key fob btw, not the main car battery in case it was not obvious.

Max
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myglaren
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Posts: 25362
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Location: Washington
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Ooops.
Previously:
2009 Honda Civic :(
C5, C5, Xantia, BX, GS, Visa.
R4, R11TXE, R14, R30TX
x 4888

Re: C5 Imobliser

Post by myglaren »

Sorry, I understood it to be the car battery.
Key fob battery should not have any effect AFAIK, that is to power the remote functions.
There is an RFID chip that is read by the car - there is an aerial in the ignition lock. The RFID is passive (unpowered) that unlocks the immobiliser.

The only time my immobiliser has tripped was when my battery died and I swapped it too quickly for a fully charged one, somewhat circumventing the removal/replacement rigmarole and the car refused to start.

Your 15 mile trip should be adequate to maintain the battery charge though.
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MaxPrimal
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Re: C5 Imobliser

Post by MaxPrimal »

Well it more 2x 6mile trips. But thinking about it I also do a short 10-15 min local run of about 3 miles each day. Yesterday my car was started/stoped a few times as I checked oil, water and other bits ready for the trip today.

Hopefully it was one of those odd blips that happens at times and will not do so again. It's now 4:30am and we leave in a hour :(

Thanks for the info tho.

Max
2008 RENAULT LAGUNA 3 EXPRESSION DCI 130 - Satnav, Bluetooth and more...
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