Hi everyone,
Jmor here, its my first time posting for help and not sure if this help request is in the correct place but if not hopefully someone will put it where it belongs (nicely of course
There is quite a lot of information here on Disco2 alarm issues and I think I've read it all but it has not helped resolve the issue hence the question (plea for help).
This is quite detailed, apologies for that.....

The problem is the alarm goes off, for no apparent reason, approximately 4 to 6 hours after I lock it with either the fob OR the key. The fob does not silence the alarm (doors open and car can be turned over) and I have to take the earth cable off the battery as it generally happens 2 in the morning. (It was funny at first seeing the old guy from next door dancing around his car at 2 in the morning with his pants on but now getting very stressed)

I have checked:
- Each door and bonnet for mis-lock warning when setting alarm with one of them open - all OK.
- Bonnet switch for water ingress, etc looks very good - OK.
- Interior movement sensors. These both look pristine but they were not plugged in. When I plugged them in I found the alarm would go off immediately. The alarm could be switched off with fob. Identified that actually only one of them was the problem and un-plugged that one.
- Receiver. Bolts holding receiver were corroded but the receiver itself looks like new. Cleaned the bolts and earth but this did not cure the problem.
- Checked fuse boxes for corrosion but no corrosion noticed.
- Replaced BCU with replacement item from Turner electrics. EKA worked to re-sync. This did not cure the problem plus I can't start the car now - engine turns over though (more on this later).

Incidentally the driver side door actuator no longer functions and the alarm issue happened sometime after this stopped working.

My next steps are:
Replace driver side door actuator.
Replace alarm receiver.
Hit starter motor with hammer.
Purchase nanocom.

Questions:
The BCU instrument cluster setting is set at petrol not diesel. Turner electrics assure me this is not related to the starting problem. Does anyone have experience in this area that this is true? Can anyone suggest how to resolve the starting issue - the car has been sat for a couple of weeks now but started ok before the BCU swap.

Any suggestions on what to about the alarm issue?
Is the nanocom the correct tool (I dont even know where to plug this in yet lol)

I love this Disco and really want to be able to keep it for a few years yet.
Thanks for your time and your help.
Jmor.

Nanocom evo is one of the tools of choice for sorting out diagnostic troubles on a D2 TD5 - it plug into the OBD II socket which is just near the driver's left knee on the lower part of the dashboard.

Basic point..... How good is the battery (the car battery!) if the Disco's been stood for a couple of weeks make sure the battery is fully charged. If it is determined that the battery is on its way out, then try a brand new battery.

There isn't a letter B showing next to the mileage readout is there? (BCU fault) Also doesn't the BCU have to learn the security code in addition to just sync'ing the key fobs? No idea of the prcodure, just a bit of heresay?

Land Rover Owner • View topic - d2 td5 bcu failure

"Replacement isnt difficult but you need access to diagnostics to program things like the key fobs and to learn the security code so that it doesnt imobilise the engine."

Thanks Difflock66. Battery is on charge and will try again tomorrow.
The bcu has been programmed to match my vehicle by turner electrics. Apart from the key syncing everything should work _ apparently.
Cheers

New battery and still not starting�� and the alarm is still going off. Sigh getting desperate.

I'm at a loss sorry! EDIT are you a member of a breakdown recovery organisation and might they try and help?

check your horn buttons on the steering wheel. they can get partially stuck down and then the horn will sound at random. usually in the early hours of the morning as i found.
until i found out what the issue was, only the removal of the fuse or disconnecting the battery would fix it.

Thanks Both.
I think one of the horn buttons was stuck - I freed them both up so we will see.
RAC man called today and told me there was a fuel problem and needs to go to a garage.
I'm soooo suspicous of the fuel setting in the bcu but have no way of verifying.
Car is being dragged to local independent LR specialist Monday.
Let you both know cheers for taking the time.
Jmor

I had similar problems to yours with the alarm going off when it shouldn't, in the end I removed the pcb in the key fob and kept it well away from the vehicle. This cured the problem, now I use the key instead of the fob button to lock/unlock. If it turns out to be a horn button stuck that's better still, good luck

Peaceful! That's how it was last night. Must have been the horn button - unbelievable.
Thanks so much xat44!
However cars has been dragged away to Mdp in raglan to sort pout the starting issue. Kind of hope it is the Bcu setting not the fuel pump ��

Fuel pump is easy to replace by the way.

Well all fixed. My new bcu was not programmed correctly and did not talk completely with the engine ECU!
I will be speaking with turner electrics shortly.......

Excellent! I'm glad you got to the bottom of the problem. What makes me more happy is the fact that I was "almost" correct in thinking that the BCU still had a problem (smug!)