2002 discovery suddern central locking fault and

Central locking was fine and all doors worked come this morning to unlovk led flashers on key fob and removes immbo light and ibterior light comes on .but wont work off the key .if i use the dash door switch .nothing st all.if i switch igition on snd press switch all doors will lock and unlock .carnt see any blown fuses .

But at the same time when i turn igition on dash beeps and a odd symblo flashers near milage looks like a letter d but with lines in middle of it ..?

Next thought id try get some faults but the disgnostic port wont let me read engine ecu .but will let me sccess everything else .any help advise please

Could be a variety of things, including a low battery voltage on the car battery, the fob battery, a bad earth connection or water on the volumetric sensors up on the cant rail on the headlining.

Electronics is a wonderful thing until it goes wrong!

Given the bad weather, I'd just pull the sensors first as it's the easiest thing to check, see if there is any water or corrosion on either side of the PCB.

Peter

Battery check tested local motist says its fine starts runs great .replaced gearbox ecu no dsh beeps do sorted something there.bttery in remotes are tested all good.remote keys are switching immo on nd off but no centrelocking fuse 1 replaced in f1 but wasnt blown. Is there any relys for central locking .and wete abouts sre these other things im looking for locted .cjeers

Most of that side is handled by the BCU Body Control Unit. If that is goosed then it's a fairly complex job to sort out, as it interfaces with the engine ECU, speedo cluster and the IDM in the passenger fuse box. The IDM actually controls the relays for the central locking solenoids.

You could try removing the connections for the passenger fusebox and cleaning up the terminals, that's always a fruitful source of open circuit connections.

Fuse 13 in the engine fusebox feeds Fuse 1 in the passenger compartment fusebox, so check that as well as Fuse 1.

Peter

Cheers peter tbh checked all fuses in fusebox under driverside dash and under bonett .looks like snother book into dealers to be sorted .bloody things these are ..

if the only problem remained is that the doors are not unlocking on the fob nor on the driver's door key but they work on the dash switch and the immobiliser reacts on the fob as it should then you need a driver's door latch assy as the switch in the actruator is gone(you should get a misslock warning but this one might be disabled)

if you still see that symbol on the odometer and it looks like a crossed B it's bad news...95% BCU internal fault, 4% IDM fault(interior fusebox), 1% the datalink between them... you need a real specialist to sort this out.

I think ur right ..as centralocking wont work off fob or work when unlocking car .and the internal central switch dosent either .unless i switch igition on first then all doirs will lock unlock off the dash switch but not of the fob ...dam thing .right so this b symblo .relates to bcm or driveside fuse box ...tempted to try a second fusebox first before i have to book it in to be fixed then

Just letting u know changed fusebox and roof reciver .b fault still shows so ill book it in gor bcu replace and recode .fingers crossed it sorts problem

Hi sounds like your disco has gone into transit mode

Hope this could be of help

Discodevon said:

Hi sounds like your disco has gone into transit mode

Hope this could be of help

Click to expand...

unsure what you mean tbh . Any easy test or fix

Transit mode is a setting that allows the car to be transported with some of the cars features disabled:

Volumetric Sensors
Passive Immobilisation
Immobilisation of the vehicle by use of door lock
Ignition key interlock
Electric Seat enable time-out with driver's door open

RAVE Page 1470

Peter

the transit/transport mode would not trigger that crossed B on the odometer but the SLS warning and completely deflated bags.
it doesnt enter in tranzit mode by itself... it's settable through tester... only if nanocom was connected to BCU it might have enabled transport mode on it's own cos nanocom used to get mad some times, but IMO it's not the case here

Cheers .ps if i remove the bcu ( think thats what its called) will it lose any codeing .also if i get a second hand one can this be recoded ..
Removed complete roof lining .4 hour job .just to double check for any dampness or leaky sunroofs there dry ..

Crazy how every was fine and following morning suddernly central locking stops .no b sign poped up this morning but still no locking ..werid everything else works

with battery disconnected, unplug and use some contact spray on the BCU's plugs(to identify it see attachment) plug it back, turn ignition to pos II and leave it so 5 minutes to fully re-establish comunication with IDM

IF it's just a locking issue see my first post here (#6) ...what's certain is that the crossed B is bad news and the BCU used to have intermittent and strange behaviaours


if you end up replaceing the BCU you can put a used one but you need a tester to sync the immobiliser with the engine ECU, programm the keys and addapt all the other equipments, T4 or nanocom can store the old BCU's settings and write them into the replacement, Hawkeye can't store them but it can sync it step by step

Plenty on Fleabay:

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Peter

you must know what mileage had the donor cos if the mileage stored in BCU is greater than yours the instrument pack will assume the higher mileage, if the mileage in BCU is lower the mileage from instrument pack's memory will be assumed.

Very helpfull advise .really greatfull for the time to help with this issuise .today before i attempted .removing bcu unit .i decided to start over and double earths .unbolt fuse box re chech all pluvs conections clean removed roof lining double checking earths and plug conections as well as checking for possible trapped wires (6hours later .i noticed damp carpet on passinger foot well .i assimed possible blocked drains .so adde jet wash and water is getting in from what looks like a rubber bulk head and waters running down wires on to carpet .as wires were damp .theres a few boxs undrr here not really knowing what there for tbh .and i resealed it tiger seal .(only thing i had handy tbh ).theres some wireing contectors that didnt look pretty tbh .so cleaned pins best i could ..everythibg plugged back in and bingo central locking is working no b code flashing but now m and lights were flashing .so cleared fault thibgs seem ok at presant but tbh i dont trust it .so booked it in to be changed just to be on the safe side .as my luck it may go in a place .and ill end up stuck altogether.many thanks for everyone helping ..best forium on the net .mind dose help when u guys know what your talkibg about unlike some are just useless...