discovery 2 central locking

Hi all,

I am new to this and I think I posted this question in the wrong thread thismorning.
I have a disco 2 td5 and my central locking doesn't work from the key fob but the doors open and lock from the drivers door, I did some fault finding and found that the plugs in passenger footwell were corroded so replaced/repaired them and now getting continuity between the reciever and BCU aswell as between the reciever plug and the earth point (n/s/r), I was getting voltage at the reciever plug (PS wire) my earth was good (B wire) and when I pressed the fob the the (BN wire) had voltage change so I presume there is a signal being sent from the transmitter key fob.
So I thought it must be the rf reciever in the roof so went ahead and bought another one fitted it and programmed key fob and it worked great but next day it stoped working so tried again to code the key fobs and just says "error no signal was reciever" so now I am thinking it must be the BCU but before I shell out on one is their a test that I can do to so I am 100% it is the BCU?

Thanks

Hi,
1. what kind of diagnostic tool was used?
2. do you have two fobs and it's the same with both?

btw, no programming is needed when the receiver is replaced, it's plug and play

Hi sierra

The diagnostic I used was autologic and yes it's the same with both fobs, I bought the second as thought it could be the fob but it's the same.
The central locking has never worked since I bought it so befor I purchased the receiver I tried to program the key fob to make sure it has been programmed properly but with no luck so then programed the key fob again when I replaced the reciever and that's when it worked untill the following day. So my guess was the previous owner maybe bought a new key (looked new when I purchased vehicle) and as the central locking wasn't working he didn't/couldn't get the key programmed.

I can't get my head around that as soon as I changed reciever the fob worked 3/4 times open/close all doors thought I cracked it untill I tried to go out in it the following morning

Hi Dickie,

So did BOTH key fobs work one day and then not work the next day?

A silly couple of things. May be worth a try, but they could be hail mary's.

Is there a chance you could move the vehicle to another place and try, to make sure you are not getting interference from an outside source. ( Automatic door / door bell ) as I have heard these can cause concerns.

Have you tried standing up close to the rear sunroof , close to the RF receiver and trying that.

Are both little red lights showing in the key fobs when the buttons are pressed.

Is you car battery fully charged, It appears some D2's are sensitive to a low battery , even if it appears OK.

Have you had water ingress into the vehicle by the BCU?

Cheers

Only the central locking is dead or the alarm too? that's important, when you lock with fob can you see activity on the alarm LED? though it's important what settings are in the BCU too cos if you can start the engine without unlocking with fob after it was locked can be 2 options: the fob-receiver link is interrupted and the immobiliser is disabled or the receiver is comunicating with the fob and then the problem is only with the central locking not BCU...more tests are needed and if you have access to that autologic again copy the BCU alarm settings and report.

Hi neilly

I didn't have the 2nd key fob when it was working I have only just purchased it to double check it isn't the original fob I have and secondly I need one as a spare.
Yes both the red lights on fobs work and also changed both fob battery's.
I assume the vehicle battery is fully charged as it starts every morning even after a few days plus like I said before the central locking did work
Yes I have tried being close to the reciever when pressing the fob but I have not tried moving the vehicle and doing it but I will try that later when I get home.
There was water damage/corrosion to the connector blocks in the passenger footwell but have repaired and clean all them now but it is a possibility that the BCU could of had damage also.

Sierra only the central locking as I have disabled the alarm with the diagnostic machine as if I keep it enabled when I lock the car via the drivers door the red led flashes and cannot disarm unless I enter the EKA code.
But yes I will take a picture of the BCU alarm options when I am home and post it hear.

Thank you both for all your help so far

But did you try to unlock with fob before you unlocked with key? important is to see if the receiver doesnt react at all to the fob or just the central locking is not working if you see what i mean so eventually enable the alarm and use the fob to see if the LED reacts on it or not, also afaik there's a receiver circuit test available in autologic menu did you try that too ?

Hi Dickie,

Just for clarification, can you please open both fobs and tell us if they both have 2 little yellow chips on the battery side of the circuit board. One will be slightly larger than the other.


Cheers

neilly said:

Hi Dickie,

Just for clarification, can you please open both fobs and tell us if they both have 2 little yellow chips on the battery side of the circuit board. One will be slightly larger than the other.


Cheers

Click to expand...

I'm curious why would you want to know that....cos that "transponder" is only for the passive remobilisation exciter coil, it has nothing to do with central locking

True,

But it may help him not make the mistake of waiting over the 30sec and allowing the immobiliser to cut back in, and think he again has an issue with the alarm. If the fobs have the chip then it will not be a problem. Thinking ahead SF.

Cheers

I have drove to another location and fobs still do not work also tried to program the fobs their also no joy.
Also opened up both key fobs like you said and my original has the 2 yellow chips in but the recent one I purchased only has the small yellow chip.

Sierra I understand were you are coming from isolating the problem if it is just the central locking or is it the alarm/immobiliser aswell so I have enabled the alarm option on autologic and still no joy from the fobs so disabled again but now currently my Immobiliser is still on untill I enter the EKA code again.
Also yes I tried the option on autologic regarding the test option for reciever again comes up with no signal was found.

Sierra this is the alarm options you were after?

I see, so you'll have to figure out what i said in my previous post then... don't you have an option in other menu to run a RF receiver test?

Sorry just seen your previous post before the pic.... in this case it's possible to be a wiring issue between the receiver and BCU rather than a BCU fault, do you have RAVE as i'll point you to the connector involved

sierrafery said:

Sorry just seen your previous post before the pic.... in this case it's possible to be a wiring issue between the receiver and BCU rather than a BCU fault, do you have RAVE as i'll point you to the connector involved

Click to expand...

Yes I do have rave.
I also thought it would be a wiring fault between the reciever and BCU but I've checked continuity between the 2 wires that run between them and both fine.

they might be fine at 3v DC(or what voltage your multimeter has) but to be some bad contact which can't be passes by that 1000baud pwm signal, the best would be to hardwire the receiver to the BCU for test before blaming the BCU IMO cos i've seen many kind of BCU missbehaviours but never such thing to not react to a good receiver, was the receiver bran new? it would be good to be 100% certain that it didnt fail again

sierrafery said:

they might be fine at 3v DC(or what voltage your multimeter has) but to be some bad contact which can't be passes by that 1000baud pwm signal, the best would be to hardwire the receiver to the BCU for test before blaming the BCU IMO cos i've seen many kind of BCU missbehaviours but never such thing to not react to a good receiver, was the receiver bran new? it would be good to be 100% certain that it didnt fail again

Click to expand...

Yep I am with you I will hard wire it to the BCU see if that has any affect.
No the reciever was 2nd hand, that is the one I fitted first then the central locking worked then following day it never so anticipated that could be a problem and contacted the seller off eBay and he sent me another replacement also 2nd hand and still the same, do you think it is worth buying a brand new one? Or maybe testing the ones I have on a friends disco 2 that has a current working central locking to prove they are working or not.

Thanks for all your input

Yes, or test the existing ones on another car or buy a new one cos it's not a killer YWY000080, around 60 quid then with a confirmed new one hardwire it to the BCU, did you check the receiver's earth on your car well?

sierrafery said:

Yes, or test the existing ones on another car or buy a new one cos it's not a killer YWY000080, around 60 quid then with a confirmed new one hardwire it to the BCU, did you check the receiver's earth on your car well?

Click to expand...

Yeah I check it from reciever to Earth connection at N/S/R just inside boot.
Probably won't get time to hard wire it now till the weekend but will let you know what I find.

Thanks again