Central Locking - Immobiliser

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Richard Martin

Well-Known Member
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Cardiff
Firstly, I have done a search and seen 100's of posts about immobilisers and central locking, but didn't see one with exactly the same problem as I have. So please don't shout at me and tell me to do a search:)

The car is a 1994 reg (1995 MY) 300Tdi Disco, with a single button fob.
I came from work today and locked it as normal using the fob. A few mintutes later I heard the alarm going off. By the time I got outside to investigate it had stopped. However the car was now unlocked. Now the central locking isn't working either on the fob or using the key in the driver's door. As well as that the car is immombilised. I can turn the ignition on and everything looks normal, but when I turn the key to start it the lights you expect to go out when starting go out, but the starter doesn't turn.

There have been no intermittent, spider, type problems before this (I think from reading stuff in the past that I don't have a spider).

Any one got any suggestions as to where to look first? Is there a fuse that might have blown (but then I would have to find out why)? Could the alarm ECU have given up? Faulty igntion switch?
 
It's deffinetly not immobilised....an immobilised one must turn, it just doesnt fire up, first of all check all earths and connections at the fuseboxes.
 
Update
I disconnected the battery and re-connected it and tried starting it. This time it started OK, but still no central locking or alarm.

I then checked the fuses that Rave says (1,2 and 5 in satellite box 1 and either 5 or 6 in two (it seemed to say 5 in one place and 6 in another). No fuses were blown.

The other thing I noticed was that the tailgate door was locked (all the others were unlocked after the alarm went off earlier).

I then decided that seeing as it is cold, raining and dark and I am getting a lift to work tomorrow that it can wait till Saturday.

Any more ideas about where to look next are welcome.
 
discool said:
If the engine doesn't crank then it's immobilised, the immobiliser is set as the same time as the alarm, so unset that and the engine will be remobilised.
Is you fob working?
Click to expand...
No the fob isn't doing anything and the key isn't doing anything in the driver's door other than locking and unlocking it.
 
You DONT have a spider, sounds like there's a prob central locking I believe there is a small plastic cam on the rear of the driver door lock to control CL via the key they can break also you have a central locking that may be faulty.
Again does the fob work you may have to re-programe it, a procedure that must be done in 8 seconds there a few threads on that.. get that working then you can start with the CL.
 
discool said:
You DONT have a spider, sounds like there's a prob central locking I believe there is a small plastic cam on the rear of the driver door lock to control CL via the key they can break also you have a central locking that may be faulty.
Again does the fob work you may have to re-programe it, a procedure that must be done in 8 seconds there a few threads on that.. get that working then you can start with the CL.
Click to expand...
I have two fobs, both worked fine until tonight, now neither work, but neither does the central locking or alarm arming work from the key in the driver's door. That made me think it was likely to be something electrical rather the mechanical in the driver's door, but I will check the cam as you suggest.

Edit
I suppose the ECU for the alarm/central locking could have thrown a wobbler and lost its link to the two fobs, so it will be worth trying to resync them, but again. If that was the problem with the fobs is it really likely that the central locking on the key would have packed up at exactly the same time?
 
Last edited:
Richard Martin said:
:) and relays
Click to expand...
Well, I've re-checked all the fuses. Taken out the alarm ECU and checked it, no sign of dry joints or anything else looking amiss.
I've have establised that it's only the central locking that isn't working. The alarm/immobiliser turns on and off using the remote and /or the key, but there is no sign of life at all from the central locking.

Rave says "If all of the lock actuators do not operate, check O and K Wire. If OK, replace Theft Alarm Unit (Z163)."

O and K are the two wires that leave the ECU and connect all the door actuators in parallel. Unless one of them is broken before they reach the first actuator its difficult to see it being anything other than a faulty ECU...which is bad news, I couldn't find any on ebay and the cheapest new one was £150. A lot of money to spend if that isn't the problem.
Any one got any other ideas?
 
In my expearance the two wires provide alternate voltage to the master actuator in the drivers door, it's that actuator the controls the remaining four via two wires.
I see there is a stand alone relay with a single button system but it's not shown what function that has.
 
discool said:
In my expearance the two wires provide alternate voltage to the master actuator in the drivers door, it's that actuator the controls the remaining four via two wires.
I see there is a stand alone relay with a single button system but it's not shown what function that has.
Click to expand...

Rave shows two relays, one to flash the indicators when you arm or disarm the system and one for the alarm sounder. So neither to do with my problem.
I've just spoken to a mate on the phone and he agrees with you about the driver's door actuator, he's convinced that if I replace that it will all be OK
 
this help?

19765d1290284721-central-locking-immobiliser-heated-rear-window-mirrors-elec-mirrors-heater-central-locking.jpg
 

Attachments

  • Heated rear window&mirrors, elec mirrors, heater & central locking.jpg
    Heated rear window&mirrors, elec mirrors, heater & central locking.jpg
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Richard Martin said:
Rave shows two relays, one to flash the indicators when you arm or disarm the system and one for the alarm sounder. So neither to do with my problem.
I've just spoken to a mate on the phone and he agrees with you about the driver's door actuator, he's convinced that if I replace that it will all be OK
Click to expand...

I have repaired a couple in the past, but after removing the door card and removing the operating rod to the lock move the the actuator rod to see if it the controls the others, there is a few mm of adjustment on the actuators mounting maybe all that is required is a bit of adjustment.

Maplin do a replacement master actuator which will work after a bit of "giggling" with the wiring connections.
 
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