Active Cruise Control on the BMW E38

**Logicsystem360** · 12-01-2019, 01:38 PM

Since lot of people are asking me, I decided to do a write up about that ACC on the BMW E38.

What is an ACC (Active Cruise Control) ?

Nothing better than wikipedia :
Adaptive cruise control (ACC) is an available cruise control system for road vehicles that automatically adjusts the vehicle speed to maintain a safe distance from vehicles ahead.

Oh my god, it's was available on the BMW e38 ? No way !

Yes, it was.
Mercedes was the first manufacturer to offer the ACC functionnality on the market, with the "Distronic" in the class S in 1999.
BMW was probably mad in 1999 and decided to bring it on the E38.
The E38 was absolutely not conceived to have ACC at the developpement, that explain the cut in the bumper, the addon on the special cluster, etc
The ACC was available in April 2000, only on european market until the end of the E38. (most are german model)

I made a video with the ACC in action in my 740i :
I must advert my channel, don't forget to subscribe, more content about my e38 will follow !
https://www.youtube.com/watch?v=Qt0tZbRYzC8

How do I know if my E38 have ACC ?

If you are asking that, you probably don't.
But there are the thing to spot to see if the E38 have ACC :

The most obivious thing is the ACC sensor :

The special cluster for ACC

I wanna retrofit it, it's possible ?

Since my E38 have the ACC from factory, I can not confirm that but I think it's possible since I saw a guy did it.

You'll need a LOT of patience and know how to use NCS expert, NCS dummy, INPA. If you don't know any of this, skip.

Does the retrofit is worth it ?

I don't know, there are a lot part to find, and there are not the cheaspiest part but the functionnality are really swag.
Keep in mind, that ACC have 20 years old, the first Golf's ACC from nowaday will be a lot better.

In case, I want to do the retrofit, which part I need ?

Non-exhaustive list :
- Front bumper with the cutting for the ACC
- ACC cache (part : 51118237079)
- ACC sensor
- ACC support
- Radiator cover (special for the ACC emplacement)
- LCM III or IV (be carreful, some III or IV don't work with the e38, just take the lastest LCM IV you will be fine)
- Lastest DSC unit (the one which can be coded the ACC)
- Cluster special for ACC
- Wiring to the DSC + ACC sensor connector
- MFL, the mark for the button is different from standard but it's just probably visual

There is a schema for the ACC

All the module need to be coded to ACC functionnality activated : (search with NCS dummy the term "ACC") :
- LCM (to display ACC events)
- Cluster
- DSC
- ACC

After all that work done, you'll need to to the alignement. The best way is to go to your dealership but if your dealership are disable (like mine) and are lost when talking to do something else than oil vidange and rob you pocket, you can DIY it. You'll need INPA (if you understand german very well) or DIS. I choose INPA for my part. Just search on Google, the procedure is the same on several brand.

Tools used by BMW :

I found that video on youtube, showing the aligement process at BMW dealership.
https://www.youtube.com/watch?v=ob8lqp_wcZQ

Found on E65 forums

You can download the BMW Service Training ACC :
http://www.febiac.be/documents_febia...ing_acc_fr.pdf

It's in French and I am sure there are a version in English, I didn't find it yet.

I have probably forget some things, just ask, I will fill up the first post.