mg zt will not lock

[madmattie]

hi all im having trouble locking my zt since removing the high line sat nav system :shrug:i go to lock as normal and it just beeps as if something is open i have checked all the doors boot and bonnet but cant see any open but when i lock manually via each door as it wont even lock via key then unlock with the remote not a problem please please help

[Polly]

Just had the same problem last week, you have a K Bus problem, try disconnecting the battery for 30minutes, although mine had a few other problems, but sorted itself by just leaving the car alone for 1 hour

[madmattie]

hi thanks i will give it a go wish i had stuck with the satnav now:duh: only changing for a double din dvd player for the kids to have a media system so thought i would sell the rest to fund this

[madmattie]

no joy still beeping at me help!!!!!!!!!!!!!!

[Polly]

Try a pm to one of the T4 guys.
Of course it could be water in the plenum, but I am dismissing such things on the basis that it is related to sat nav removal

[Polly]

Did you remove wiring? Perhaps removed seats

[madmattie]

no just removed stereo cd player satnav and tv control unit and stereo control unit plus a white box that stops the double din unit going in

[madmattie]

how do you get hold of the t4 guys also i did remove the white box behind the stereo i have now since refitted it could that be the problem :shrug::duh:

[klarzy]

possibly disturbed the BCU.... have you done the battery reset..?

[madmattie]

i have disconnected the battery pos and neg

[klarzy]

For at. Least half an hour?

[polinsteve]

Perhaps you could disconnect new and try it and if that shows no improvement, reconnect the old. That would definitely show where the fault lies.

[Mike Noc]

Failing to lock and getting the beep is usually because the driver's door isn't shut.

Anything else open and the car will still beep but it will lock what it can.

[Polly]

Could it be that you might have disconnected the sat nav before the light went out?

[egremont]

A local 75 owner had a similar problem with his remote key not locking the doors.

This started after he had a flat battery and Roadside Assist started his car – probably by using jumper leads.

Following that saga, his remote key refused to lock the doors. He tried “everything” including disconnecting the battery for 20 minutes plus.

He mentioned that in sheer frustration, he pulled out two fuses, “numbers 5 and 8 – body control units”. After 20 minutes, he replaced the fuses, and the fob keys worked again.

I don’t understand why this was successful when disconnecting the battery earlier didn't have the desired result.

[klarzy]

A local 75 owner had a similar problem with his remote key not locking the doors.

This started after he had a flat battery and Roadside Assist started his car – probably by using jumper leads.

Following that saga, his remote key refused to lock the doors. He tried “everything” including disconnecting the battery for 20 minutes plus.

He mentioned that in sheer frustration, he pulled out two fuses, “numbers 5 and 8 – body control units”. After 20 minutes, he replaced the fuses, and the fob keys worked again.

I don’t understand why this was successful when disconnecting the battery earlier didn't have the desired result.

This is possibly due to residual voltage in capacitors around the system.
A full 30 mins is required for all of them to totally discharge when they are all connected, if however you pull some individual fuses you do in effect isolate the individual system and that can then dissipate faster than if connected to the whole as it is not feeding from all of the other components.

We used to place a resistor across the disconnected battery leads to bleed charge off faster but I do not know if that will have a detrimental effect on the 75/ZT's systems.