General Adaptive Cruise Control

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General Adaptive Cruise Control

It seems we may have been six months late in starting this thread - someone was selling a BMW stalk and radar module rather cheaply last year!

https://www.bimmerfest.com/forums/showthread.php?t=632783

The thread is quite an interesting read, according to them (though it may be BMW's own take on the system?) the ACC doesn't adjust the speed relative to distance but actually adjusts it relative to time. Still uses a four-position 'wheel' to select either one second up to four seconds. I kind of see how this way of calculating it works...providing my maths is correct! Converting the national speed limit of 70mph into mps (metres per second) I get a little over 31mps, now if you selected the highest time setting of four seconds you get a distance from the vehicle in front of 124m, which is round about the range of the first gen. radar module.

But perhaps all that is unnecessary? If in fact the ACC DOES in fact calculate its distance from the car in front based on current speed and time then maybe we can avoid the guesswork of the resistance values for the time setting and have a variable resistor in its place?
 
The thread is quite an interesting read, according to them (though it may be BMW's own take on the system?) the ACC doesn't adjust the speed relative to distance but actually adjusts it relative to time. Still uses a four-position 'wheel' to select either one second up to four seconds. I kind of see how this way of calculating it works...providing my maths is correct!

Yes - actually, the eLearn documentation Davren posted refers to time as the base measurement, so FIAT are really describing the same system operation as BMW. The distance gradually increases as the speed increases.

The programming inside the radar sensor node will be similar (if not identical) for BMW as for FIAT, since all the vehicle-specific tasks (calculating wheel size, distance, braking capacity, outside temperature etc.) appear to be performed by other nodes on the CAN bus.

The way that systems like this work (e.g. rain-sensing wipers) is that a component supplier (Bosch, etc.) develops the system, and the vehicle manufacturer just puts the relevant requirements (or pre-disposition, as FIAT calls it) into the car. Of course it would be possible for Bosch to develop a different, incompatible system for FIAT at the same time as the system for BMW... but hopefully, they wouldn't have bothered.

The big concern over this retrofit - whether the other nodes (body computer, instrument panel, engine ECU, ABS ECU) have all the necessary programming to enable this system. For example, yes, the ABS node has the capability to brake the car (on vehicles with ESP) - but does it have the programming to 'listen' for the ACC messages?

It is perfectly possible for FIAT to put different software in different versions of the car. I wouldn't be surprised at all if only the earliest Stilo Abarths had the programming, since over time, a number of other features were removed from the later models.

We need to try and obtain one of these first-gen radar sensor modules, and connect it to the wiring connector present in the front-right wheelarch, and then do a proxy-alignment to see if the node is detected. That's the first step, and it also assumes that the connector wiring is compatible (which it seemed to be from reading the pinouts, although as Richy pointed out, the plug shape may be different).

It is illuminating to see the difference between BMW's approach - of making a retrofit kit available, then introducing an improved version on new models - and FIAT's approach - of denying all knowledge after the press release has made them look good. :) Here we are, ten years on, and no effort has been made by FIAT/Alfa Romeo to equip any later model with the system or a development of it. I guess FIAT make a lot more money more easily from selling new 500s cheaper than before, and in different colours, to existing 500 owners. Maybe that's why BMW is the 'aspirational brand' success story (3-series being one of the UK's top-selling cars).

-Alex
 
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the way i have always understood ECUs on the stilo is that 'non specific' ECUs such as Body Computer have all the relevent info in, regarding all spec levels of stilos available. so a BC on a 1.2 Active is exactly the same as a BC on a fully spec'd 2.4. the part that differs is how the other ECUs and Control units hang off the BC... THE only part i am worried about is the ABS ECU and the engine ECU(M10) for the 1.6, in my case.

now as a few posts have already mentioned, as long as the ABS ECU supports ASR it should be compatible with the ACC system. mine has ASR so i am now only worried about the engine ECU.

my own *revised* theory on this is that the radar unit controls the regulation of speed, via the CAN network, upto the the speed set by CC switch which is maintained/capped by the Engine ECU.

bear with me on this but i hope you will see my reasoning.
View attachment 112096
B2 Fuseboard
M1 Body Computer
M10 Engine ECU
M87 Radar unit
H7 super fangled dangled Cruise Control Stalk with the 'distance ring'

12v feed comes from B2 into M87 and H7. 'distance setting' is controlled by resistors inside H7 and then the remaining voltage is fed to M87... for example 3v, 6v & 9v for close, medium and long distances. the magic that happens inside M87 is Bosch's handywork but i suspect a '+', '-' or 'hold' signal can then be sent over the CAN to whichever ECU will listen. namely M10 and ABS ECU. the line fed from M87 Pin5 through D97 seems to be a diagnostic line to the OBD2 connector just routed through M1. in my experience this will be a 'k-line' diagnostic feed for diag of M87.

M87 regardless of its manufacturer or other industry uses has to be able so spit out these '+', '-' or 'Hold' signals. it just so happens that the Bosch 0 203 000 044/001/064 is mentioned as being the BMW ACC1 (ACC2 seems to work over longer distances so **MAY** not be compatible with the stilo, on the other hand the ACC2 units might work!) i know i researched the 044 number and im 99.9% certain that it related to the Stilo and BMW 7series hence why BMW is mentioned. what i havent researched yet is if any of the later incarnations of ACC1 modules are still compatible with the earlier versions of the BMW system.

this all makes sense in my head if i havent explained it right please say so were all on the same page
 
seems like the radar unit runs over the CAN and communicates to the ECU via CAN, theres no feed wires into the Engine ECU like a straight CC install

edit:- after talking with MT... this might help a little, high speed CAN Layout
highspeedcan.jpg
 
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the way i have always understood ECUs on the stilo is that 'non specific' ECUs such as Body Computer have all the relevent info in, regarding all spec levels of stilos available. so a BC on a 1.2 Active is exactly the same as a BC on a fully spec'd 2.4.

There are several different Body Computers available for the Stilo range, but when you order one from Fiat, they won't supply it without the VIN. I assume this is so they can program it to the individual car's options.
.
 

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Dave... ruining dreams but giving useful info, as ever!

would the VIN requirement just be a software build from factory fit node spec... so if extra nodes were added a PA would have to be carried out anyway? or is there different software relating to 1.2, 1.4, 1.6, 1.8, JTD or 2.4 as an engine spec not a node build spec?
 
Plenty of people have retrofitted something into our stilos without issue, although trying to add in a node that didn't even make production is still a long shot. There's enough information from eLearn regarding the wiring that some sort of make shift ACC can be fitted to any spec of Stilo, when it comes down to communication on the can lines it's anyone's guess. I delicate myself to be the guinea pig.
 
get your balls out and spend £100 then...

http://www.ebay.co.uk/itm/BMW-ACC-RADARSENSOR-/190934384215?pt=DE_Autoteile&hash=item2c74937e57

edit:-
i just had a word with a guy i know who knows far too much crap about everything ever in life i asked him

im looking at a bosch radar unit for the adaptive cruise control... the part number is 0 203 000 ### the last 3 digits seem to differ wildly yet the unit *seems* to stay the same (external casing and electrical plug) in your experience do these last 3 digits relate to massive changes in production?

he replied with
It is likely that the last three digits determine the calibration for each car model (Calibration being an Eprom change, embedded software, it could be dip switched, it could be variable potentiometer or similar. And it is unlikely to be easy to spot.), so the device is common but the calibration makes it vehicle model specific. I make this guess based on my knowledge of OEM supplier part numbering on electronic systems.
 
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after spending hours and hours on ePER all i can find, in standard trim is 60688209 which is a Lancia number for the Thesis. search it on ebay, Nothing, search it on google, nada... might be time to send Fiat an email! ive sent a message to a seller on ebay regarding a 2002 options list which may or maynot list ACC as an option on the Stilo.
 
Thesis Screenshot... this part is a shade under £3000... YES 3 GRAND!!!

nothing is listed in ePER for any version of Stilos or Alfas in relation to this ACC Radar unit. E412 is the designation for ACC where as the stilo only ever lists an E416 (CC designation) for any of their equipment.
 

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so MT has brought up a bit of a game changer... whilst all the wiring diagrams show only 6-Pins for all the ins and outs of M87 (ACC Radar Node), M87 itself is actually a 12-pin unit.

i have been chasing completely the wrong Radar modules from BMWs and getting a little narrow minded in my efforts. MT is helping and bringing up some valid points and questions regarding ACC. heres some more info thanks to Mark for bringing this up, far too late, last night!

heres what M87 actually looks like according to eLearn (strangely reminiscent to the Thesis unit from ePER :rolleyes:)
radar.jpg

and the Pinouts are as follows
  1. Gnd.
  2. C-CAN High
  3. B-CAN Low
  4. C-CAN Low
  5. N/A
  6. Programming Pin for Radar Processing Unit (sets controller into 'Bootstrap Mode')
  7. N/A
  8. B-CAN High
  9. Analog 'Headway' Setting
  10. N/A
  11. K-Line (for Diag.)
  12. +ve feed from F35

i have emailed Bosch technical this morning and had a word with my vaguely local Fiat independant (Grays in Warwick) and ill post the replies if/when i get them back from Bosch and Fiat. if anyone has anything they would like me to ask upon receiving a reply please post in here or PM me and ill include it!

also... AS OF YET it seems that ACC is only compatible with the 2.4s, i personally think it sits closely to the Selespeed boxes so non Selespeed vehicles wont have the code in the ECUs to implement this. this will probably have the likes of #AlexGS and #Gadge rubbing their hands together. but this WHOLE thread is, at the moment, surmising and dolly day-dreaming about what could be one of THE COOLEST mods to the lower spec'd Stilos. Unfortunately the 'Distance ring' CC Stalk is also a MASSIVE issue. i.e. its unavailable from what i can (or can't) find. i think this will put most people off the mod if they cant make it OEM but this is yet to be seen. maybe if Fiat come back with something solid i might be able to shine a light in their eyes and slap them about a bit and see if Fiat, Alfa or Lancia actually do a seperate 'Distance Ring' Stalk. i know some of you are running Alfa CC Stalks.
 
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In regards to the options list I had a reply from the eBay seller

'...'Radar Cruise Control' was only available as an optional extra on the Stilo Abarth.
It was not standard or optional on any other models.Normal Cruise Control was Optional on the 1.6 Active and 1.6 and 1.8 Dynamic and standard on the Abarth. (1.2 and 1.9 80 JTD engines did not have any sort of cruise control)
Hope this helps...'

And the reply from Grays was
'...*I have searched*through the Stilo electrics*on*e-per but can`t find anything matching this diagram.
The only option for cruise control I can find relates to the column switch.*I can`t find any technical information on site or a technician that has worked on one.
I*recomend the Fiat tech site www.technicalinformation.fiat.com

Thanks for your enquiry...'

Fiat listed it as an optional extra in 2002 but nothing remains to take a reference from if you ask an independent dealer. The tech info site requires a vat number to register from what I can make out but I havent had the time to properly have a look
 
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In regards to the options list I had a reply from the eBay seller

'...'Radar Cruise Control' was only available as an optional extra on the Stilo Abarth.
It was not standard or optional on any other models.Normal Cruise Control was Optional on the 1.6 Active and 1.6 and 1.8 Dynamic and standard on the Abarth. (1.2 and 1.9 80 JTD engines did not have any sort of cruise control)
Hope this helps...'

And the reply from Grays was
'...*I have searched*through the Stilo electrics*on*e-per but can`t find anything matching this diagram.
The only option for cruise control I can find relates to the column switch.*I can`t find any technical information on site or a technician that has worked on one.
I*recomend the Fiat tech site www.technicalinformation.fiat.com

Thanks for your enquiry...'

Fiat listed it as an optional extra in 2002 but nothing remains to take a reference from if you ask an independent dealer. The tech info site requires a vat number to register from what I can make out but I havent had the time to properly have a look

Ah well expected response but would have been nice to get some technical info or diagrams off them.

It's all fine and well them saying what models the cc was an option for but Fiat didn't bank on us being able to hard wire our own cc stalks to the D4 or the ECU (1.2 only) or just connect the stalk the wiring they left inside the steering column did they? My point is if the JTD and 1.2/1.4 never had cc as a listed factory option yet the ecus on board have the capacity the run it if installed then maybe there just bull****ting with the ACC only working on the 2.4
 
Ah well expected response but would have been nice to get some technical info or diagrams off them.

It's all fine and well them saying what models the cc was an option for but Fiat didn't bank on us being able to hard wire our own cc stalks to the D4 or the ECU (1.2 only) or just connect the stalk the wiring they left inside the steering column did they? My point is if the JTD and 1.2/1.4 never had cc as a listed factory option yet the ecus on board have the capacity the run it if installed then maybe there just bull****ting with the ACC only working on the 2.4

Dont shoot the messenger... the item for sale was an original 2002 options list Booklet for the fiats of that time... he wouldn't have had any further info.

Dont think of it as Bull****ting... someone somewhere will know/have the info on ACC on stilo ECUs... I think we're just asking the right questions to the wrong people.
 
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