75ZT Community

kandyman wrote:

Mofo wrote:I have it, on very good authority (I won't reveal my sources just yet) that I suggest fuse 8 passenger compartment fusebox, and fusible link 3E (50A) underbonnet fusebox should be investigated. It should also resolve the intermittent Central Locking problem too.

I will even supply FOC a 50A underbonnet fuse to help this diagnosis if it is required...

Morning Mofo,

Thanks for the advice.

Found a fuse number layout.

I see that F8 is a 5a immobiliser to the instrument pack.

What does the 3E 50a do ?

As the fault is intermittent do you think a remove and reseat and a good talking to would be the way to go ?

Thanks

It's the supply busbar fuse for passenger compartment fusebox 33 and 34 (RADIO & HEVAC)
Fuse 8 IPK (Instrument pack (IPK from the German)) EWS (Engine immobiliser (EWS from the German, Elektronik WegfahrSicherung)) may be an issue re the strange locking symptoms you're experiencing

kandyman wrote:

Mofo wrote:I have it, on very good authority (I won't reveal my sources just yet) that I suggest fuse 8 passenger compartment fusebox, and fusible link 3E (50A) underbonnet fusebox should be investigated. It should also resolve the intermittent Central Locking problem too.

I will even supply FOC a 50A underbonnet fuse to help this diagnosis if it is required...

Morning Mofo,

Thanks for the advice.

Found a fuse number layout.

I see that F8 is a 5a immobiliser to the instrument pack.

What does the 3E 50a do ?

As the fault is intermittent do you think a remove and reseat and a good talking to would be the way to go ?

Thanks

That's a very good question.....and I apparently have a very good answer.....ahem....

It supplies busbar fuse for PC fusebox 33 and 34.

There you go

rover214brian wrote:

kandyman wrote:

Mofo wrote:I have it, on very good authority (I won't reveal my sources just yet) that I suggest fuse 8 passenger compartment fusebox, and fusible link 3E (50A) underbonnet fusebox should be investigated. It should also resolve the intermittent Central Locking problem too.

I will even supply FOC a 50A underbonnet fuse to help this diagnosis if it is required...

Morning Mofo,

Thanks for the advice.

Found a fuse number layout.

I see that F8 is a 5a immobiliser to the instrument pack.

What does the 3E 50a do ?

As the fault is intermittent do you think a remove and reseat and a good talking to would be the way to go ?

Thanks

It's the supply busbar fuse for passenger compartment fusebox 33 and 34 (RADIO & HEVAC)
Fuse 8 IPK EWS may be an issue re the strange locking symptoms you're experiencing

That's strangely familiar to what I discovered from my "source".....

kandyman wrote:

JohnDotCom wrote:You coming to see me then Andy?

Maybe next year and ill bring Deb.

That would be very nice.

It's sounding more like a kbus fault to me, I'm afraid. Fuses rarely go intermittent. It could be one of the screws in the busbar / maxifuse. I've seen similar-ish symptoms caused when that 150A maxifuse blows, but I can't swear they are all the same. Certainly the fact that most of that list still works tends to rule a power feed out, and point more towards kbus. It could be as simple as a broken wire to the BCU (Body Control Unit) since it contains the bus pullup resistor, or it could be broken at the IPK because the IPK sends the ignition on message to the highline satnav.

It is worth checking the accessory feed to the IPK, fuse 15 in the passenger box. It might be loose, rather than blown. Fuse 8, by the way, is just so the IPK knows the engine is cranking, it isn't as such a supply to the IPK, and it comes from the immobiliser which is working OK according to the OP.

Thanks again for your input,

I pulled a few fuses and did a few scews up and wiggled a few wires and the fault still comes and goes.

The only thing that has not worked properly is the head unit display the radio some time works but not the display.

I was going to look at booking it in to one of the local auto electrical places but worried that it might get worse rather than better and we get stuck up here.

I'm sure you have done it, but check your wheel well isn't wet in the bottom. The video module is on kbus and could be the culprit.

Duncan wrote:I'm sure you have done it, but check your wheel well isn't wet in the bottom. The video module is on kbus and could be the culprit.

Checked the wheel well and its all dry.



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Duncan wrote:It's sounding more like a kbus fault to me, I'm afraid. Fuses rarely go intermittent. It could be one of the screws in the busbar / maxifuse. I've seen similar-ish symptoms caused when that 150A maxifuse blows, but I can't swear they are all the same. Certainly the fact that most of that list still works tends to rule a power feed out, and point more towards kbus. It could be as simple as a broken wire to the BCU since it contains the bus pullup resistor, or it could be broken at the IPK because the IPK sends the ignition on message to the highline satnav.

It is worth checking the accessory feed to the IPK, fuse 15 in the passenger box. It might be loose, rather than blown. Fuse 8, by the way, is just so the IPK knows the engine is cranking, it isn't as such a supply to the IPK, and it comes from the immobiliser which is working OK according to the OP.

Duncan, try removing fuse 8 next time you T4 (Testbook version 4.Computer Diagnostic System) a car, after the car has been started using the key, the remote central locking will unlock, but not lock the car.
A battery off reset, or a "reconfigure all ecus" restores central locking until the starter is operated again.
The first time I encountered this, I was convinced it was a K-Bus fault too
Brian

Update.

Well the fault is still here.

We drove home from fife to kent and the fault presented it self on and off for most of the drive.

Today I replaced the 3 maxi fuses in the engine fuse box and all the 5amp fuses in the in car fuse box, while I was under there a gave push/pull/wiggle to the fuses and wires but as I dont do electrics I didn't know what's what

Well the fault is still there

I went to my local auto electrical shop but the guy is away till next Thursday so not much I can do till then.

Is the fault something that would get picked up by a T4 ?

Thanks

I'm still of the opinion that it is related to one of the fusible links Andy. I'd need to be at the car with my test meter to go any further though. No idea what a T4 session would show up.

raistlin wrote:I'm still of the opinion that it is related to one of the fusible links Andy. I'd need to be at the car with my test meter to go any further though. No idea what a T4 session would show up.

I should of stopped by yours yesterday on my way back from Scotland

If it's something that you're happy to look in to I'll be happy to drive up to yours.

We're away on holiday this weekend Andy

raistlin wrote:We're away on holiday this weekend Andy

Well I think you should cancel


Have a great holiday and if my local auto guys can't fix it I'll give you shout after your holiday,if I bring treats maybe I'll get Duncan to come along and cast a expert eye over the car.

Thanks

Duncan is only a hop, skip and jump up the road from me Andy, as a percentage of your overall journey. I know he is snowed at the moment but it might be worth asking if he can help if you get your car to him.

Also, it is the nano meet, weekend after we get home if you aren't sorted by then

It might also be worth looking under the fusebox. I have heard of one owner, who came to a Nano, where the connectors on the underbonnet fusebox had become a problem. I can't remember whether it was one underneath, or the big screw on one at the top. It had gone high resistance and was causing things to get hot, he said. It had been replaced by the time I saw the car so I don't know any more.

An aside. It may not be the connection itself, but where the big cable goes into the terminal. I do remember seeing on other models, where the cable becomes loose inside the crimp. This would likely be the one where the big cable connects near the 150A fuse.

I took out the under bonnet fuse board this afternoon,

Well I didn't take it out completely but undid it so I could access the connectors blocks underneath.

I unclipped each of the clips and removed the connector one at a time and gave the wires a tug/pull/wiggle, I couldn't see anything that looked wrong to me.

I removed the 150amp mega fuse and cleaned the contacts (they were clean already) and checked the power/earth cables and they looked fine as well.

The short 5 minute test drive I carried out didn't throw up any errors but I'll have to wait till I carry out some more test drives tomorrow to see if the fault returns.

Thanks

Well I had all my fingers n toes crossed but the fault came back.


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I found a thread from Bernard which lists the same faults.

bcu-problem-t3905.html#p69620