ACC & City Braking - How Its Done -

[Dellmassive]

ACC & City Braking - How Its Done -

what is it?

Adaptive cruise control (ACC)
Adaptive cruise control (ACC) is a speed control system with intelligent control of the vehicle speed.
The system accelerates and decelerates comfortably. Adaptive cruise control is a combination of a speed
and distance control system.

Structure and function:
The radar sensor fitted in the front of the vehicle continuously measures the distance and speed of the vehicle
driving in front. Using the ACC controls on the multifunction steering wheel, the system can be activated and
deactivated, and the required speed and following distance can be set.
In vehicles with dual clutch gearbox (DSG), braking takes place to a standstill depending on the situation. ACC maintains a preselected speed and a defined distance, accelerating and decelerating automatically. Automatic moving-off is not possible.
The dash panel insert displays all relevant information about the system such as the required speed and warning messages. The driver is solely responsible for the behaviour of the vehicle in all driving situations. He/she can influence the driving situation at any time by switching off the ACC, or braking or accelerating himself/herself. The ACC is subject to system limits during driving. If these limits are reached or exceeded in the driving situation, the driver is informed and presented with a visual message to take over the function.

Operating limits:
If the detection capability of the radar sensor is impaired due to heavy rain, snow or dirt, the distance control and
speed control are deactivated automatically. The dash panel insert displays "ACC – no sensor function". As soon as
the impairment has been rectified, the driver can reactivate ACC control.






Lets look at the components . . . .







3 - Securing nuts
q Qty. 2
q 8 Nm
4 - Retaining plate with adapter frame
q Serves as mounting bracket for adaptive cruise control unit -J428-
q With adjustment screws for adaptive cruise control unit -J428-
5 - Electrical connector
6 - Adaptive cruise control unit -J428-
q Removing and installing → Chapter
q Calibrating → Chapter
7 - Adaptive cruise control button -E357-
q Integrated in multifunction steering wheel



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So thats the main section . . . .

lets look at the wiring . . . .

Adaptive cruise control unit, Onboard supply control unit, Isolation relay for powertrain CAN bus, Fuse 14 on fuse holder C, Fuse 37 on fuse holder C
J428 - Adaptive cruise control unit
J519 - Onboard supply control unit
J788 - Isolation relay for powertrain CAN bus
SC14 - Fuse 14 on fuse holder C
SC37 - Fuse 37 on fuse holder C
T8a - 8-pin connector, black, near horn, dual-tone horn
T8b - 8-pin connector, black
T9 - 9-pin connector, black
T73a - 73-pin connector, black
T73b - 73-pin connector, white
13 - Earth point, on right in engine compartment
372 - Earth connection 7, in main wiring harness
B285 - Positive connection 9 (15a) in main wiring harness
B303 - Positive connection 7 (30), in main wiring harness
B383 - Connection 1 (powertrain CAN bus, high), in main wiring harness
B384 - Connection 2 (powertrain CAN bus, high), in main wiring harness
B390 - Connection 1 (powertrain CAN bus, low), in main wiring harness
B391 - Connection 2 (powertrain CAN bus, low), in main wiring harness






So the Radar unit J428 is connected directly to the main BCM via a shunt relay,

Radar unit pinouts:
t8b/1 - 0v
t8b/8 - SC37 (fuse holder)
t8b/2 - B384 - Connection 2 (powertrain CAN bus, high), in main wiring harness
t8b/3 - B391 - Connection 2 (powertrain CAN bus, low), in main wiring harness


The isolation relay is there for security reasons so that the CAN bus is isolated from the wiring outside the main body of the van to stop CAN bus probing attacks.

The relay J788 (Isolation relay for powertrain CAN bus) connects B391 to B390 and B384 to B383 data lines together.
B383 - Connection 1 (powertrain CAN bus, high), in main wiring harness
B384 - Connection 2 (powertrain CAN bus, high), in main wiring harness
B390 - Connection 1 (powertrain CAN bus, low), in main wiring harness
B391 - Connection 2 (powertrain CAN bus, low), in main wiring harness


The relay is powered via SC14 and is 0v switched via BCM (J519) (t73a/8)


The next piece is the Buttons for the MFSW that are needed to control ACC.

Multifunction buttons on left in steering wheel, Coil connector, Alarm horn, Driver door control unit, Front passenger door control unit, Onboard supply control unit
E440 - Multifunction buttons on left in steering wheel
F350 - Coil connector, in steering wheel
H12 - Alarm horn
J386 - Driver door control unit
J387 - Front passenger door control unit
J519 - Onboard supply control unit
T5u - 5-pin connector, black
T10 - 10-pin connector, black, in E-box in engine compartment
T10al - 10-pin connector, red, in right A-pillar coupling station
T12ae - 12-pin connector, yellow
T16k - 16-pin connector, black
T16l - 16-pin connector, black
T17l - 17-pin connector, black, in left A-pillar coupling station
T41 - 41-pin connector, grey
T73b - 73-pin connector, white
B528 - Connection 1 (LIN bus) in main wiring harness
B549 - Connection 2 (LIN bus) in main wiring harness
* - Only models with electric window regulators
*2 - For models with anti-theft alarm system
*3 - Only models with no adaptive cruise control (ACC)
*4 - Only models with adaptive cruise control (ACC)
*5 - Only models with no anti-theft alarm system
*6 - Only vehicles without electric window regulators



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There are other considerations and inputs but these are all picked up fron the CAN and Powertrain CAN.

The ABS, SRS, AEB, Front Assit, are all part of the system via the CAN bus.

EDIT: @dnoermann has identified that there may be two different ABS units.

Looking into ETKA, there are two different ABS Units for T6.

- SW: 7E0 907 379 Q HW: 7E0 907 379 N with ACC Support
- SW: 7E0 907 379 P HW: 7E0 907 379 M without ACC Support (City Breaking possible)


The rest seems to be just software coding . . . . .

The coding has been discussed over here: Got city braking thingy.....want adaptive cruise control...possible?



coding will be needed for the MFSW and Enable ACC with Front Assist etc etc.

ill update this thread with the definitive coding once confirmed.

Credits to:

@Pauly
@Loz
@mmi
@Adams
@New2t6

 

[Dellmassive]

page held for additional data.

coding specific info going here >>>>>>

 

[Shaun Witts]

Great information! Well laid out, thank you.

However, I can’t tell whether any further additional hardware, beyond a suitable MFSW, is needed?
For example, does the Dash Panel Insert need replacing with one that has the relevant control unit in it?

 

[Dellmassive]

Great information! Well laid out, thank you.

However, I can’t tell whether any further additional hardware, beyond a suitable MFSW, is needed?
For example, does the Dash Panel Insert need replacing with one that has the relevant control unit in it?

what dash panel insert? The clocks or something else.?

by the looks of it:

you need all the above, ie MFSW with ACC switches for control, and city braking radar. + coding. the rest seems to be already programmed in to the BCM/ECU.

the other user settings for the ACC are via the dash MMI menu (once coded)

the ACC is basically just software that uses the above hardware plus other viairous inputs from the van.

its looking like that if you already have city braking radar then its an easy upgrade with a MFSW and coding . . . . .

but if No Radar already then you need that extra hardware also plus the above.



seems like a plausible MOD, though HazzyDayz hasnt got it listed as yet . . . .

HazzyDayz - Transporter 7E 2016> - T6


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[mark]

A while back I read about a German main dealer that had ordered a van with the 99mph ACC when the customer had ordered the higher speed version .

When the main dealer contacted the factory about upgrading the acc they were told it wasn't possible and a new vehicle would have to ordered.

Theirs so many safety concerns with a system controls braking I've a feeling the factory will have this locked down pretty tight.

 

[Shaun Witts]

what dash panel insert? The clocks or something else.?
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Item 1 in your Overview of fitting locations above.
It looks like the MFD, but also has a control unit that may be specific to ACC?

If it is as simple as fitting a suitable MFSW, and re-coding, then I will be ordering a new MFSW forthwith!

 

[Dellmassive]

Item 1 in your Overview of fitting locations above.
It looks like the MFD, but also has a control unit that may be specific to ACC?

If it is as simple as fitting a suitable MFSW, and re-coding, then I will be ordering a new MFSW forthwith!

Oh I see, item 1 is just the MFD

Standard as per the dash pods that are fitted... like high line Etc.

 

[Dellmassive]

A while back I read about a German main dealer that had ordered a van with the 99mph ACC when the customer had ordered the higher speed version .

When the main dealer contacted the factory about upgrading the acc they were told it wasn't possible and a new vehicle would have to ordered.

Theirs so many safety concerns with a system controls braking I've a feeling the factory will have this locked down pretty tight.

This is of course very possible... someone needs to the first to try.

I've got it fitted from factory so can't test the theory.

 

[PetroHeed]

Nobody tried this yet?

Can just the button be bought for an existing MFSW?

 

[Joerg]

So let me get this straight, my t6 came with the MFSW and city braking/warning.

The button which is normally the ACC on my steering wheel is just a blank but I assume you can buy the single button separately? So once I get hold of this it’s just a matter of coding the ACC and then calibrating it?

Thanks

 

[PetroHeed]

So let me get this straight, my t6 came with the MFSW and city braking/warning.

The button which is normally the ACC on my steering wheel is just a blank but I assume you can buy the single button separately? So once I get hold of this it’s just a matter of coding the ACC and then calibrating it?

Thanks

Thats what Id like to know, Id assume the button clusters come as 1 piece to buy, but Id be surprised if it was that easy. I've now sold my van so wont benefit me now..

 

[Littleblackflash]

Good work. I love a simple electrical upgrade. I wonder how much the parts cost?

 

[Shaun Witts]

The button which is normally the ACC on my steering wheel is just a blank but I assume you can buy the single button separately? So once I get hold of this it’s just a matter of coding the ACC and then calibrating it?

If someone can confirm that it is this simple - especially by pointing to a successful ACC upgrade - then I would be well happy and ordering the parts immediately!

 

[Joerg]

Pretty sure this is the buttons and the ribbon to go with it

5g0959442k

But not yet tried it yet

 

[James fitch]

If someone can confirm that it is this simple - especially by pointing to a successful ACC upgrade - then I would be well happy and ordering the parts immediately!

No, doesn’t work like this.
I’ve got the buttons and tried. If you plug them in you’ll get all sorts of errors when switching on ignition.
With VCPsystems it appears that the area for changing the ecu is locked down. I don’t believe it is possible to retro ACC, no matter how simple similar it may seem, but welcomed to be proved wrong.

 

[Dellmassive]

Id imagine an ODIS session would sort it.

VCDS is still untested.

VCP shows ECU locked?

 

[James fitch]

No VCP shows the option to change is locked.

 

[James fitch]

I don’t think you’ll ever get to work unless you take it somewhere with the VAS 6430 VAG alignment machine to recalibrate the adas..

 

[Wango]

You guys are talking a foreign language

 

[Pauly]

I asked around about this and its been suggested this is a SwAP function, basically not happening without ODIS at a minimum if its even possible (think discovery media headunit moving vehicles or adding factory functions aka a PITA ! )