Audi side assist canbus connection

RussJ · Aug 18, 2018

Just taken the car out for a drive to see if I could replicate my wifes experience with the warning lights coming on. Nothing for me but traffic was light so possibly just not enough cars around.
However I did notice that if the on/off switch is pressed after a startup the side assist goes through a self test where both LEDs light up for a couple of seconds before the error message appears.
This suggests to me that the wiring and modules are OK
However, I also noticed that only three of the four LED cells in the drivers side were showing, so it looks like I have the same issue as before but on the other side?
Can't believe both lights have failed so soon...
Back to Audi on Monday for a new one.

Morski · Aug 18, 2018

What type of cable did you use to make the CAN wires? Have you measured the voltages of the CAN to establish that its stable?

RussJ · Aug 18, 2018

I've removed my canbus wiring extension bodge and its now back to original.
The canbus error has gone.

RussJ · Aug 21, 2018

Gave myself the weekend off... but spent yesterday re-checking my wiring.
I found a difference between the written instructions and the wiring diagram.
The written instructions say that a loose, unterminated cable needs to connected to "lighting" - ie a switched live, which I did.
However, the wiring diagram show the same wire being connected to pin 17, connector t32b of the "onboard supply unit".
According to the manual this is located under the dash but on my car its at the back on the drivers side. There was no pin in terminal 17 so I added one.
When I switched on the ignition, pin 17 did not become live.
Do I need to code this module to let it know that Side Assist is fitted? If so how?
Russ

myounus · Aug 22, 2018

RussJ said:
Gave myself the weekend off... but spent yesterday re-checking my wiring.
I found a difference between the written instructions and the wiring diagram.
The written instructions say that a loose, unterminated cable needs to connected to "lighting" - ie a switched live, which I did.
However, the wiring diagram show the same wire being connected to pin 17, connector t32b of the "onboard supply unit".
According to the manual this is located under the dash but on my car its at the back on the drivers side. There was no pin in terminal 17 so I added one.
When I switched on the ignition, pin 17 did not become live.
Do I need to code this module to let it know that Side Assist is fitted? If so how?
Russ

Hi Russ
In retrofits it's quite normal adding additional wires to the bcm but I'm not familiar with what that particular bcm and what pin17 would represent. Coding would be in Module 09 but that depends if the bcm has a pin there or not? If you remove the plug check to see if there is an actual pin on the bcm itself for pin17 to connect to.

RussJ · Aug 23, 2018

I screwed up here! There are two onboard supply units apparently, one in the front dash area and the other in the rear. The rear one is for "convenience" items so I was wrong to try and connect to it.
I still can't see where the front one is. According to Etka its a big black box with multiple connectors so should be obvious but I can't spot it. There are some individual square 17pin connectors which look like relays but I'm after a 32pin version.
My manual is supposed to be up to MY '17 but I'm wondering if its actually older and doesn't reflect later cars' setup.

myounus · Aug 23, 2018

The onboard power supply unit is normally referred to as a bcm or body control module, module 09. It is usually located behind the dashboard somewhere. It you look at ETKA it should show you it's location

m87a · Aug 23, 2018

it should be above pedals in driver foot well area

RussJ · Aug 24, 2018

m87a said:
it should be above pedals in driver foot well area

I was convinced that it had been moved so went out and bought a newer version of Elsawin which covered my model year.
Much to my surprise the bcm was still shown as the same position, so I got a torch and crawled into the drivers footwell.
Sure enough, right up under the dash top and hidden behind wire bundles and other stuff I found it.
I've spliced into pin 17/connectorT32b as per the wiring diagram but ran out of time yesterday to finish and test.
My new warning light has now come into stock at the dealer so hopefully I'll be able to complete the job today.
I'll report back with the outcome...
Russ

RussJ · Aug 24, 2018

Finished off the work this morning, installed my new LED warning light, switched on and - same bloody error codes!
When I switch on the ignition I can see Side Assist in the features on the MMI and I can even change the brightness of the warning lights.
However, as soon as I press the on/off switch I get a chime and a message saying that SA not available and the option is greyed out.
Switching off and on again resets everything once more.
VCDS reports no errors until I hit the switch then its the familiar "open circuit or short to power".
Pin 17 on the front bcm provides switched 12v as expected.
Running out of ideas now...
Russ

downtime · Aug 26, 2018

I checked the connection diagram from ElsaWin as well.

I would again double check the connections.

K233 drivers side LED. Pin 1 connected to kl30 line. Which means battery connection. So it's not going to switched +12v kl15. Pin 2 is connected to pin4 of lane change unit 2 (not 1).
K234 passenger side LED. Pin1 again to kl30 line, battery hot. Pin 2 to pin 2 of lane change unit 2.

kl30 line is also going to lane change unit 2 pin 6.

The BCM pin17 connection is only providing the button background light for the lane assist button. It's connected to pin1 of the button connector.

RussJ · Aug 26, 2018

downtime said:
I checked the connection diagram from ElsaWin as well.

I would again double check the connections.

K233 drivers side LED. Pin 1 connected to kl30 line. Which means battery connection. So it's not going to switched +12v kl15. Pin 2 is connected to pin4 of lane change unit 2 (not 1).
K234 passenger side LED. Pin1 again to kl30 line, battery hot. Pin 2 to pin 2 of lane change unit 2.

kl30 line is also going to lane change unit 2 pin 6.

The BCM pin17 connection is only providing the button background light for the lane assist button. It's connected to pin1 of the button connector.

Many thanks for taking the trouble to check out the wiring diagram and suggest some checks I could make. Its been raining here most of the day so I haven't had a chance to investigate further. However, I did compare your notes against a spreadsheet I made detailing the wiring connections/terminals etc and it matches your comments. I'd post it here but I can't see how to add an attachment. I'll have a look tomorrow if the weather improves.

Uwe · Aug 26, 2018

RussJ said:
I'd post it here but I can't see how to add an attachment.

We don't do attachments here. For text data, just post it in-line. If it's a spreadsheet, upload it to Google Docs, share it, and post a link.

-Uwe-

RussJ · Aug 27, 2018

As suggested by Ewe, this is a spreadsheet showing all the interconnects:

https://docs.google.com/spreadsheets/d/1KC5IqYgvT6ixcaSGtT1UjHauOEXbwG04sax0uVEiw7E/edit?usp=sharing

I checked continuity from the module connectors to each wires final connection, so I'm reasonably confident that the wiring is OK.

The warning lamps are showing 12v on the permanent live but also approx. 10v on the return wire to the modules. This is what puzzles me, does the voltage leak through the LEDs?

downtime · Aug 27, 2018

Check this one for reference :
https://www.audiworld.com/forums/q5...29/audi-q5-side-assist-retrofit-done-2900841/

Also do you have J769 and J770 right way around? On MQB the higher number is Master and lower is Slave. And the master module is installed to passenger side rear not driver.

RussJ · Aug 27, 2018

The modules are handed and will only fit in the bumper in one position.
However, if you read back in my posts I did initially manage to wire them up the wrong way round.
There was a conflict between the written instructions I found on the internet and the wiring diagram on Elsawin.
Once I realised my mistake I swapped the bumper loom around so that the modules were correctly plugged in.
On my car 769 is the Master (part number ending ..566B) and 770 the Slave (...568B)
My concern is that I may have damaged one or both modules by plugging them in incorrectly.

downtime · Aug 27, 2018

Something is not correct there as what you wrote that the ground voltage from the leds is 10v. So there's a leak or incorrect connection.

If you look at the link I attached in my previous response, the led pin 2 on both sides is actually connected to lane change assist module 2 pin 2 and NOT grounded to the door ground. Both modules are then grounded to frame in grounding spot behind D pillar. Most likely you can use the grounding spots anywhere inside the car.

Check the grounds again that they really are grounded properly. If it's feeding voltage to both sides then it would explain the error message.

Edit :

And quickly looking from the diagram, basically you cannot do any harm by plugging the modules wrong way around. Both modules have pin 9 defined as supply voltage so you could've not burned anything with that.

RussJ · Aug 27, 2018

I've just double checked - I'm getting 12v on the warning light battery feed and 8.7v on both the return wires to the module, even when the main loom is separated from the bumper loom.
If I touch the return wires with a 12v tester, the LED light flashes on.
I just can't figure out how the return wires pick up voltage unless it leaks through the LEDs.

I had seen Vikislaps post but I think its for a pre-facelift car as the wiring is quite different to the Elsawin diagram.
On my car the return wires from the warning lights are not joined but go to 2 and 4 on the Slave module.

Uwe · Aug 27, 2018

RussJ said:
As suggested by Ewe, this is a [...]

-Uwe-

myounus · Aug 27, 2018

RussJ said:
I've just double checked - I'm getting 12v on the warning light battery feed and 8.7v on both the return wires to the module, even when the main loom is separated from the bumper loom.
If I touch the return wires with a 12v tester, the LED light flashes on.
I just can't figure out how the return wires pick up voltage unless it leaks through the LEDs.

I had seen Vikislaps post but I think its for a pre-facelift car as the wiring is quite different to the Elsawin diagram.
On my car the return wires from the warning lights are not joined but go to 2 and 4 on the Slave module.

Hi Russ

I would suggest drinking a strong cup of coffee or 2 then starting from scratch again. In your previous posts you have extended wires, removed the extensions, fed them to the convenience module and then removed them, etc. etc. It's possible that a wire or some are damaged and shorting, who knows!

When I retrofit I separately tape the new wires in Tesa tape and then attach/stick them onto the original loom so I am aware of my additions and I am 100% sure that they are shielded with no breaks. Yes it's time consuming and a lengthy process but it works out in the long run. The only reason I'm suggesting this is that if you encounter some other issue further down the line, you will then be 100% sure that these wires are not the cause.

If that's too much then keep on going and see how you get on....

Audi side assist canbus connection

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