# Can-bus question



## Bungle11 (Feb 10, 2021)

I have a 7 seat F46. I see that there is not a section for this particular 2 series, but here's hoping that someone can explain a potential issue with the Can-bus.

I intend to fit a towbar to the car, and will be fitting aftermarket dedicated electrics. The control box is made by Jaeger and it only needs a few connections. The instructions for hooking up to the Can-bus show to connect to the multi connector high up in the wing next to the 3rd row of seats. But to reach that I would need to remove the trim card which requires removal of the 3rd row seats (and all the wiring to the seat belts).
There is another option to run the twisted pair to the front footwell and connect to the black 54 pin multi plug pins 49 and 50. But this requires removing plastic trim to reach, and I don't like removing trim in this cold weather as it can be brittle and crack. 
However, the instructions state that if these 2 pins are already occupied then to crimp onto the twisted wires already connected to 49 and 50.

SO..... to the meaty part of this post.
In the boot there is a Can-bus pair which are going to a box on the rear panel. This could be the control for the tailgate, or the reversing camera - I don't know which. It would be so much simpler to crimp on to these as they are easily exposed. But I am wary of connecting to these as I don't know whether these are the main Can-bus that are the equivalent to those in the front footwell. Is there is a rear gateway, and is it that these wires are not the main Can-bus, i.e. is this just info from the boxes mounted on the rear panel and might therefore throw up some codes?
Can anyone experienced on Can-bus in BMW's shed any light on this please?

Many thanks

Jeff


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## mr_bean (Mar 20, 2009)

There are several different CAN networks so there's a chance that won't work. Is there a part number on the box on the rear panel?
That will tell us what the module is and then we can determine which CAN network it's connected to.


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## Doug Huffman (Apr 25, 2015)

Bungle11 said:


> SO..... to the meaty part of this post.
> In the boot there is a Can-bus pair which are going to a box on the rear panel. This could be the control for the tailgate, or the reversing camera - I don't know which. It would be so much simpler to crimp on to these as they are easily exposed. But I am wary of connecting to these as I don't know whether these are the main Can-bus that are the equivalent to those in the front footwell. Is there is a rear gateway, and is it that these wires are not the main Can-bus, i.e. is this just info from the boxes mounted on the rear panel and might therefore throw up some codes?
> Can anyone experienced on Can-bus in BMW's shed any light on this please?
> 
> ...


There are nine engine versions in the 2’ F46 MPV. I’ll pick one and see what I can figure out.

With the 218i engine I found listed Power Train Car Access Network PT-CAN and K-CAN and FlexRay network and all over the car.


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## Bungle11 (Feb 10, 2021)

Doug Huffman said:


> There are nine engine versions in the 2’ F46 MPV. I’ll pick one and see what I can figure out.
> 
> With the 218i engine I found listed Power Train Car Access Network PT-CAN and K-CAN and FlexRay network and all over the car.





mr_bean said:


> There are several different CAN networks so there's a chance that won't work. Is there a part number on the box on the rear panel?
> That will tell us what the module is and then we can determine which CAN network it's connected to.


Thanks Mr Bean, I'll take a look and trace the wires. Thanks for the quick reply!

And Doug, it's a 220i B48 petrol 192hp.
I was wondering if there was a gateway or something up in the rear quarter, as the instructions show to connect to any spare pair of pins in that connector. So, thinking a bit more, it does seem likely that the red/yellow twist that I found is one of the sub-buses (if that's a word).

Many many thanks to both of you!!!


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## Bungle11 (Feb 10, 2021)

Mr Bean,
The red/yellow twisted pair wires go to the control box with part number 102135-10. I found the part number 102135-10 which links to 61357412310 by looking on google which describes it as the tailgate or decklid control box.
I'd be very grateful if you could tell me whether this is the main can network.

Many thanks
Jeff


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## mr_bean (Mar 20, 2009)

The wiring diagram isn't giving me wire colors, but here's what I can tell you.
The instructions you have for wiring into the footwell module on pins 49 and 50 means this is supposed to connect to the K-CAN2 bus. Luckily, the tailgate control module also connects to K-CAN2; it should be pins 5 and 6 on the 10 pin connector.
I'm assuming the instructions don't call this out because the auto-tailgate is an option and it won't work for everyone.


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## Bungle11 (Feb 10, 2021)

mr_bean said:


> The wiring diagram isn't giving me wire colors, but here's what I can tell you.
> The instructions you have for wiring into the footwell module on pins 49 and 50 means this is supposed to connect to the K-CAN2 bus. Luckily, the tailgate control module also connects to K-CAN2; it should be pins 5 and 6 on the 10 pin connector.
> I'm assuming the instructions don't call this out because the auto-tailgate is an option and it won't work for everyone.


Many, many thanks for that information.
If I look at the connector, the pins are not numbered, but: I see two heavy wires, Live feed looks like it might be pin1and Ground looks like it might be pin2, then two medium weight wires, possibly pin 3 and 4, and if so, that makes Can High in 5, and Can Low in 6. Is this right?

If I connect to that pair and the towing module doesn't work properly, will there be any damage or fault codes appearing?

Edit: I've just zoomed in to my photo and can see that Can H is in 5 and Can L is in 6. 
My old eyes can't see things that close up, even though I'm short sighted, so the photo has revealed the numbers. Maybe time to get some new varifocals!!!

Thanks!
Jeff


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## mr_bean (Mar 20, 2009)

Yes, CAN H is red wire at pin 5. CAN L is yellow wire at pin 6.
I've never heard of anyone causing permanent damage by tapping into the CAN erroneously. Usually, the worst that can happen is the towbar module causes noise/interference on the CAN and all the other modules on the CAN go haywire. Disconnecting the towbar module should revert everything back to normal. This was actually very common in the early days of CAN networks on cars. People would tap into the CAN when installing an aftermarket radio and either ground out the CAN or send 12V through it - and then be utterly confused by the results.

Of course, the obligatory statement - I'm not responsible if something goes wrong.


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## Bungle11 (Feb 10, 2021)

mr_bean said:


> Yes, CAN H is red wire at pin 5. CAN L is yellow wire at pin 6.
> I've never heard of anyone causing permanent damage by tapping into the CAN erroneously. Usually, the worst that can happen is the towbar module causes noise/interference on the CAN and all the other modules on the CAN go haywire. Disconnecting the towbar module should revert everything back to normal. This was actually very common in the early days of CAN networks on cars. People would tap into the CAN when installing an aftermarket radio and either ground out the CAN or send 12V through it - and then be utterly confused by the results.
> 
> Of course, the obligatory statement - I'm not responsible if something goes wrong.


Thanks for the reassurance.
I'll be using Posi-taps as I really don't trust the Scotchloks supplied with the kit as they can cut a few of the conductors (I know from 49 years experience fixing cars). I've sorted out quite a few friends' cars towing problems caused by Scotchloks.

One last question.... Do I need to disconnect the battery before tapping in?
The instructions say to do so, but both their methods involve removimng multi-plugs which I know for sure would cause all sorts of errors.

Thank you so much for taking the time to help me.

Best regards
Jeff


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## mr_bean (Mar 20, 2009)

It's always a good idea to disconnect the battery when doing electrical work.


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## Bungle11 (Feb 10, 2021)

mr_bean said:


> It's always a good idea to disconnect the battery when doing electrical work.


I shall do that!

Thanks again. You are so helpful!!!!!!


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## Bungle11 (Feb 10, 2021)

Dear Mr Bean,

Just to finalise, the interface is fitted, and my car is now ready for towing!

I really can't thank you enough for your help!

Jeff


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## feedtalefive (Mar 4, 2021)

I'm assuming the instructions don't call this out because the auto-tailgate is an option and it won't work for everyone.  get-vidmate.com instasave.onl


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## Bungle11 (Feb 10, 2021)

feedtalefive said:


> I'm assuming the instructions don't call this out because the auto-tailgate is an option and it won't work for everyone.


The instructions (Brink 703478) cater for a range of BMW and Mini models: The F39,40,44,45,46, and F48, as well as Mini F54,55,56 and F60. So, yes you are correct that the instructions don't call for this connection as not all these ten models have a powered tailgate. That's why they tell you to connect to a multi-plug in the rear quarter, forward of the fuel filler, or to the plug in the front passenger footwell as this is common to all the above.
However, the F45 and F46 (mine) in UK spec do both have a power tailgate as standard. I wanted to keep all the wiring easy to connect without removing a load of trim, and I also wanted to keep wiring as short and localised as possible; that's why I was keen to do what I did. And as a bonus, this 66 year old learned a lot about canbus systems.


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