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Old 19th December 2019, 14:54   #1
Busboy
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Default Car won't unlock and dis-arm alarm on either fobs

I can't unlock my Facelift CDTi Tourer on either of the two fobs but it will unlock on the key but when door is opened alarm goes off as BCU presumably knows to set off alarm, so Battery unhooked and alarm stops, I have locked on key , re- connected battery but alarm still active, then all of a sudden all doors will lock and unlock on fob but alarm still active so off it goes again, I have checked bonnet sensor and it seems to be working, and during all this I can actually start the car!

It was recommended by my MGR mechanic to unplug the BCU and plug back in but all still the same and also all door actuators are working.

It seems that at the moment the car has decided not to recognise either fob to disarm.

This is doing my head in - HELP!

NOW FIXED - Thanks to the helpful advice from Yorkshire GOC.
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Last edited by Busboy; 20th December 2019 at 18:30..
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Old 19th December 2019, 20:06   #2
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Try a fob reset place key in door lock and press lock or unlock button four times to re-sync the fob, the chip is inside the key hence the physical connection.

Have heard folk say this has sorted the keys.
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Old 19th December 2019, 20:21   #3
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The usual answer to this is that the ECU is in a pool of water but I expect you have already checked the plenum.----
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Old 19th December 2019, 22:29   #4
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Quote:
Originally Posted by Yorkshire GOC View Post
Try a fob reset place key in door lock and press lock or unlock button four times to re-sync the fob, the chip is inside the key hence the physical connection.

Have heard folk say this has sorted the keys.
Thanks I will try this tomorrow!
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Old 19th December 2019, 22:30   #5
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Quote:
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The usual answer to this is that the ECU is in a pool of water but I expect you have already checked the plenum.----
I have checked the plenum through. My spyhole it's all dry, thanks anyway
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Old 20th December 2019, 10:52   #6
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Quote:
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I have checked the plenum through. My spyhole it's all dry, thanks anyway
I had this issue. The disconnecting of the battery is resetting the system, which allows it to work only once, my alarm did not sound, but then at the time it was n/s. It was a 7.5a fuse (brown). I cannot recall the number of it, but 36 sticks in my mind, but don't quote me, but it was a brown 7.5a fuse. I believe it covers the BCU (there are at least two for this) as well as other things. Replaced the fuse and all was well - and has been for nearly 6 years.
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Old 20th December 2019, 12:53   #7
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https://the75andztclub.co.uk/forum/s...69&postcount=1
https://the75andztclub.co.uk/forum/s...11&postcount=7
Thanks again Brian.

Last edited by Heddy; 20th December 2019 at 12:55..
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Old 20th December 2019, 13:14   #8
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had similar on our 1.8 , found the Sounder PCB was corroded due to damp? .. worth a look and just unplug or repair/replace



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Old 22nd December 2019, 09:30   #9
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Was this issue fixed? Could the OP post up please for the benefit of members with future similar issues
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Old 23rd December 2019, 07:12   #10
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See advice from Yorkshire GOC.
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