Discovery 1 Alarm/Central locking Problem

[exiiled-geordie]

Hi,I am new to the forum and this is my first post.I have a 1997 R reg Discovery V8 with a central locking/alarm problem.Basically the central locking doesn't work,either with the key,by pressing the lock button down manually or by using the remote.The alarm system does not work either.The LED doesnt flash at all and the alarm doesn't function at all.The vehicle has an aftermarket immobiliser fitted but I don't think the factory fitted one works.I have checked the connections on the alarm/central locking ECU and all seems fine.There is however a red wire which comes out of the unit and goes nowhere.The ECU has a cable clip stuck onto it which holds this wire.Is this normal? Am I right in thinking that if I get another alarm/locking ecu with the remote that goes with it,that it will just plug in and work?The part number on the ECU is AMR6429.Am I also right in thinking that the V8 and Tdi ECUs are different?Sorry for the long post but it is really annoying having to manually lock all of the doors.

 

[discool]

The V8 ECU is different from that of a Tdi, and only Tdi's with electronic diesel control have ECUs.
It sounds that whole LR fitted alarm and immobilised has been disconnected so any thing could have happend. The alarmn and central locking ecu s are seperate so so if you have a fob for the alarm and they haven't been removed why do u need to replace them, as it sounds that u have a wiring problem with spare wires around.

You have a lot of testing to do so you will need a mulitimeter and a diagram of the alarm wiring if you can find one, it may be better to put it all in the hands of a vehicle alarm engineer to sort out.

 

[exiiled-geordie]

Sorry when I was saying the ECUs were different between Tdi & V8 I meant the alarm/immobiliser ECU. I thought that on the later Disco 1s that the alarm and central locking were operated by the same control unit,the green one under the dash on the passenger side.My remote is the 2 button type. I assumed that as neither the locking or alarm are working that the control unit was faulty. I take it from your reply that the red wire that is clipped onto my control unit should actually go to a wire on the vehicle? I just wondered if it was an aerial or something.

 

[discool]

I don't have a diagram or colour code for the two button system so i haven't a clue on the red wire it's not an aerial thats within the alarm ecu which is the same for either diesel or petrol.
Two button fob systems have seperate units for alarm and central locking (a black box in a similar position to the green alarm one) it may be just a case of powering up the alarm & C/locking ecu and fitting a new fob battery to get it working, but then some wiring may have been used for the 3rd party immobiliser thats been fitted, who knows.

 

[John_P]

Hi
The is a short wire out of the rear (I think) of the 2 connectors that is the aerial but cannot remember the colour off hand.
This wire is aprox 8-10 cm from memory and often has the end bared which always seemed odd to me?

The are at least 3 fuses to the alarm system which should be checked.

All alarm functions immobiliser, hazards, curtsey lights, mis-lock sounder, led indication etc can be disabled via programming this method usually leaves the central locking working.

If you hook it up to a diagnostic tool you may be-able to see what's happening including reading live data of master lock position, door switches etc which may help diagnosing any faults.

Where in the country are you?

John

 

[exiiled-geordie]

Hi you mention that there are 3 fuses for the alarm system but I have only checked the one on the main fuseboard under the drivers side dash panel.Do you know where the other fuses are? I have removed the drives door trim and checked out the mechanism in there and everything is there and looks to be working ok.This led me to think that it was the alarm/locking ecu that was faulty.I am in Kirkby Stephen,Cumbria.

 

[John_P]

Hi
Your about 80 miles 2hours + on the back roads and < £50 on fuel from me, an intendant land rover specialist should run a quick diagnostic for that, if your stuck you could come over and I'll plug in my Hawkeye.

Fuse 1 (15a)and fuse 5 (10a)Satellite fuse box 1
Fuse 4 (30a) engine bay fuse box.

John

 

[exiiled-geordie]

Hi
Thanks for that, I will check the other fuses in the morning. There is a decent independent not far from here so I will give them a try if I have no joy with the fuses. I didn't realise that a problem like this could be tested with a diagnostic tool.

 

[exiiled-geordie]

Hi John
Many thanks for your advice about the fuses.I had no idea that there was more than 1 fuse for the locking and alarm and it doesn't tell you on the fuseboard cover that the fuses you mentioned were for the locking. Turns out it was Fuse 1 on the Satellite 1 fuse box that had blown.Popped a new one in and everything works as it should.I feel rather stupid now that it was just a fuse but many thanks for your advice.
Den

 

[John_P]

Hi
I take it you mean the whole system is working again alarm, alarm led and central locking?

By the way the after-market immobiliser that has been fitted does it use key-fobs like this

with the word Eureka on the back?

If so it most likely had a spider failure in the past, spider replacement parts have been obsolete for a long time but LR did a plug in kit YWJ500020 for Discos and defenders with spiders.

This immobiliser is a passive system and works independently from the vehicles alarm system.

John

 

[exiiled-geordie]

Hi John
Yeah the whole thing is working now,alarm,locking and LED.And yes that is exactly the immobiliser that I have.How did you know that?When you say that it most likely had a problem with the spider in the past,does that mean that I may have problems with that still?
Den

 

[John_P]

Hi
Glad your all fixed up and only cost you a fuse and some time!

The PO of your vehicle obviously cared for the vehicle having it repaired correctly.

The original spider immobiliser AMR4889 had a weakness and often suffered from failure in the soldered joints causing intermittent or complete failure to start the vehicle.

Your vehicle would appear to have suffered from this or the spider has at some time failed.

The spider unit is buried deep in the centre of the dash have a look at this web page
http://forums.lr4x4.com/index.php?showtopic=86 for more info.

The cheap and cheerful fix for this is to replace the spider with a by-pass AMR4956 cost around £7
but as the name implies it by passes the security features of the immobiliser, starter inhibitor, fuel pump or stop solenoid leaving the vehicle more vulnerable to theft and higher insurance premiums.

The original spider unit was discontinued some time ago but Land Rover produced a replacement Immobiliser Kit part number YWJ500020 for Discos and Defenders it plugs into the vehicles wiring harness using the same connector as the original spider it replaces (addition of one wire to attach to an ignition feed).

As you have a YWJ500020 immobiliser fitted (in-place of the AMR4889 spider) your vehicle no longer has the original spider so will not suffer from this problem.

Your 'new' immobiliser YWJ500020 retails at around £200, plus the labour cost of fitting I would not be surprised if the previous owner paid £500+ for this repair at a Land Rover Dealer probably a lot more if it needed to be recovered then put on testbook diagnostics to try and identify the problem etc.

Its far to common to find Discos and Defenders with some sort of spider bypass fitted leaving them far to easy to steal, they may still have the alarm working but no one takes any notice of sirens and flashing lights these days.

John

 

[exiiled-geordie]

I can imagine that the previous owner would have done the job properly if the condition of the vehicle is anything to go by.It is way better than the 2 previous Discos I have had.(A 1995 ES Tdi auto & a 1995 ES V8(LPG) manual).There have only been a couple of age related jobs needing doing,the most annoying of which was the central locking. Only a leaky rear sunroof to sort now and the car is sorted.

 

[John_P]

Get that sunroof sorted pronto even if it's just a temporary bodge with silicon sealant before the rear floors start to rot away

 

[ibmj]

Hi,
I would like to ask if any similar problems (with imobilliser spider unit) were reported for Disco Series 2 (1999-) petrol?
If YES, could the replacement link AMR4956 be used?
Regards
Ivan

 

[discool]

Welcome to the forum, D2's dont have the "spider" as they have a different security system although it has a similar function.

 

[Fraserp33]

I have a problem with central locking on my 1995 300tdi disco. Single button remote will unlock passenger door only, when I unlock with driver's side with a key the drivers and passenger door unlocks. The back and rear doors only unlock when I pull up each individual button and lock the same way. The key fob will engage the alarm and immobilizer so the spider is still in circuit.
I am tempted with starting off by replacing driver's door lock actuator first but I am in the dark as to whether I should diagnose before swapping parts willy-nilly. Any ideas where to start?

 

[discool]

I have a problem with central locking on my 1995 300tdi disco. Single button remote will unlock passenger door only, when I unlock with driver's side with a key the drivers and passenger door unlocks. The back and rear doors only unlock when I pull up each individual button and lock the same way. The key fob will engage the alarm and immobilizer so the spider is still in circuit.
I am tempted with starting off by replacing driver's door lock actuator first but I am in the dark as to whether I should diagnose before swapping parts willy-nilly. Any ideas where to start?

It’s possible that the actuator (master) within the drivers door is faulty or wiring to the (slave) actuators.
All the wiring to the slaves is run parallel so common when pressing the button the master actuator operates unlocking or locking the drivers door, within the master there‘s a micro switch which provides the 12 volt to all the slaves, so they all operate simultaneously.
So a fault with the master actuator micro switch or wiring to the slaves not receiving the 12 volts.

When using the key in the drivers door unlock/lock is mechanical via the connecting rod from the back of the key to the door locking mechanism, but the actuator also moves to provide the 12v to all the slaves Via its micro switch.
You will need to check for voltage at the master and slaves, the actuator fixing on the door is adjustable if found that there 12v but the actuator doesn’t move fully to operate the lock.
Slaves are 2 wire and the master is 5 wire.

Thats about it… later 300 series disco had two button fobs, u must have an earlier 300 fitted with a 200 single button fob Security syste.