General: 850: immobiliser nightmare!!!!!!!!

[jingham86]

Hi can anyone help in giving me advice on how to swith off my immobiliser. I have a volvo 850 2.5 ( M Reg) which up until now has been very reliable But the battery needed changing, so i replaced the old battery with the new. Now everytime i open the car door the alarm goes off.I can't turn the car on or drive it either. I have searched the manuals and internet to get help but have had no luck.I checked all the paperwork that came with the car nothing of what related to immobisers was there can anyone help!!!!! Dave.

[ShadeTek]

Try removing fuse 6 from the fusebox.

[Jod T5]

Originally Posted by ShadeTek

Try removing fuse 6 from the fusebox.

fuse 6 is for the central locking and is used to release the central locking when the imobiliser is set and as part of the reset proceedure....
what type of body have you OP, as brian correctly suggests the fuse 6 does play a part in the reset proceedure, i will hazard a guess you have an estate so try setting off the alarm, remove fuse 6 then fuse 16...wait a minute and then replace fuse 16 followed by #6...
this should reset the system, failing this the next thing is to remove and replace the central locking/alarm relay....
cheers
jod

[dadsavage]

great info my 850 tdi saloon locked me out,changed remote batteries,no joy took out number 6 fuse stopped the alarm and allowed me to start the car, took out number 15 fuse then re-fitted them both and seems to of re-set the remote central locking/imobiliser phew!!!!!!!!!!!!!

[Cookeh]

Bit of a thread necro, but thanks Jod.

I've just acquired an 850 T5 estate and when first viewing the car (battery was dead and being recharged) the immobiliser activated. The dealer was a bit of a cowboy apparently and remedied this by removing fuse 6 - and so disabling my central locking. I thought the immobiliser issue had been properly fixed, but when trying to sort out my central locking last night I discovered that 6 was missing. Plugged it back in and low-and-behold the immobiliser issue reappeared.

Removing fuse 6, then 5 and waiting before putting them back in in reverse order has seemed to fix the immobiliser and give me central locking on the key - I still don't have the remote central locking working however, but I figure not to push my luck in one day!

[ShadeTek]

Wow, it's been eleven years since this thread and I haven't posted in this forum since 2012 so hello again. From what I remember if you get a new remote from the dealer, there are 2 types. They will bring both out to the car and then you turn the ignition off and on 5 times and then you press the remote until the alarm led changes. Then try switch off the ignitiion and see if the doors lock. I know this as I bought a new one in 2003-ish and that's how to programme the remote to the car.