LE500 alarm question

Recently I've not been able to fob lock my LE500...whenever I'd try to..well most of the time anyway...all I get is a beep from my horn and the door locking buttons stay up...

If I lock using just the key the door locking buttons go down.

I've performed the alarm test and everything I check results in the alarm light illuminating except for when I try and test the volumetric sensor...when nothing at all happens.

My conclusion is that the volumetric sensor is faulty. Would you agree? Or could I have missed something?

..can I just remove the sensor or do I have to replace it?

It does point to a faulty volumetric sensor because locking the car with the key enables the alarm but disables that sensor. It's so you can lock the car with say a dog or child inside.

Whether you can just disconnect the sensor, I don't know.:shrug: But it's worth a try.

Thanks David...that's my next step..to see if the fob lock regains its ability to lock..

BTW for those who have an LE500 the part number for the volumetric sensor is YWC000690...same as for the last MGR TFs...

I unplugged the volumetric sensor and the fault remained...so it's not that..still sure that it isn't working coz the alarm test says it's not...but it not working is not the reason for the fob lock generating a beep!

So plugged back in again...investigated the boot catch and electrics..dismantled..cleaned and lubed...still the same problem..

I investigated the boot lock first coz the door/boot/bonnet open warning light came on the other day...and I got out of the car and slammed the boot...problem solved..

Now going to tackle the drivers door, passenger door and front boot..at the moment I suspect the drivers door coz that's the only other thing that changed after the warning light came on....

Boot switch Check:
With the boot open the boot light should be on, put the shank of a screwdriver into the boot latch and trip it to lock, the boot light should go out, unlock with the key, the latch should trip open and release the screwdriver, boot light should come on.

Boot Loom Wiring:
The other thing to check for while you are in that area is the integrity of the boot loom wiring i.e. when the lock is open it sends a ground signal to the BCU. There are many problems related to the boot loom due to broken wires going open circuit or shorting against another wire. I don't know if this was resolved or modified on the LE but worth a look. as it was a known issue on the F/TF from day one.

Door switch Check:
Passenger and drivers door open switches are inside the lock mechanisms, open either door and the interior light should come on, close the door and the light should go out after 15 seconds.

Door lock barrel switch check:
When you lock using the key the divers sill button will go down mechanical as it's connected via the rod, but does it activate the central locking? i.e. is the passenger door locking via the lock motor? if not then it's one of the lock barrel micro switches sticking, similar for opening. which will confuse the BCU.

BCU Re-set
The other thing to try before you start to open too many thing up is:
Make sure the alarm is off i.e. engine can start, make sure both sill buttons are raised (car is unlocked and not immobilized) disconnect the positive battery terminal and put it to ground/earth to discharge any capacitors that are holding energy, re connect the battery, this should have re-set the BCU and give it a try.

Let us know how you get on.

Brian.