Servotronic on a 335i

doublespaces

Administrator
Oct 18, 2016
7,609
AZ
So a bunch of people have swapped the M3 steering rack into their cars, but the servotronic is not enabled and there is no assist at low speeds. A member on another forum gave this tip:

Hope this helps guys....

I found that on a 1m the JBE controls the servotronic (pretty sure the dme does on a m3)

Hopefully that means that we can make servotronic work on our cars by possibly programming/coding the jbe and wiring it up

So the wires from servotronic go to the large connector on the back of the JBE/JB connector (X14270)

Pin 5 (black wire with brown stripe)
pin 6 (black wire with white stripe)

These are not listed in ANY wiring diagram, with factory diagnostic software it says those pins are not used. I verified by checking continuity between the servotronic connector and the pins at the jbe. Its 100% accurate.

The ZB number of the jbe that has working servotronic is 9264577

Remember this is on a 1M, im 80% sure this will work on a e90. It should work for sure on a 135i.

GOOD LUCK!
So I'm thinking there has gotta be a way to make this work with some coding trickery. Did anyone get this working or know how to enable it? @Levanime @WedgePerformance

Update - I asked if he had made any progress and this is what he said:

yes I was able to have a coder turn it on in the jbe. need a higher output PS pump though for good assist. Havnt got around to doing that. needs a 1m power steering pump. they are expensive
 

AzNdevil

Corporal
Nov 4, 2016
234
Hong Kong
You missed this image and the procedure:DShamelessly copied and pasted from http://www.1addicts.com/forums/showthread.php?t=1137304&page=3

Thing is...where did this diagram come from? M3 is controlled by DME and 1M has an Active Steering Controller..

Implementation of Servotronic is not difficult with a bit of electrical wiring and coding.

+ and - wires needs to be taken from the valve on the rack to pins 5 and 6 on the rear plug on the junction box. Routing the wire is interesting and requires pulling apart some scuttle covers to get at the box where the wires go through the bulkhead.

The fusebox needs a 10 amp fuse at position 5. From there the car needs the servotronic option added to the car. The option number is $216. The next part is the one that was difficult to ascertain from all previous threads but in the end was very simple. NCS expert is required to activate the Servotronic valve in the JBBF2 ecu.

An interesting aside is that as a result of using the standard steering pump rather than a M3/1M unit the effort is a bit higher if you try turning the wheel while the engine is idling. I suspect the standard pump is smaller and needs a little bit of revs for full assistance to kick in.

attachment[1].jpg
 

Kommodore

Private
Nov 5, 2016
48
Cactus Farm
The only thing to keep in mind is that if you decide to run the beefier pump you should also upgrade your power steering cooler. CSF makes one. The M3 had a power steering overheat issue from track days iirc.
 
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doublespaces

Administrator
Oct 18, 2016
7,609
AZ
The only thing to keep in mind is that if you decide to run the beefier pump you should also upgrade your power steering cooler. CSF makes one. The M3 had a power steering overheat issue from track days iirc.
You know, I thought I had read in another thread a guy got the servotronic working by wiring it up with an arduino or something. He didn't mention anything about the assist being bad?
 

doublespaces

Administrator
Oct 18, 2016
7,609
AZ
And here is a post from Muppet from that 1addicts thread:

So I think I have now got this sorted. I had a bit of a problem with the placebo effect as I would try something, restart the motor and move the wheel and think it is lighter. It is only when you turn to full lock do you feel the additional load that is required without Servotronic. In addition past 30 kph the additional weight is really not a factor.

To answer the post above they are basically the same rack. Same ratio, same fitment apart from the hydraulic pipes may be slightly differently oriented.

The issue has been whether you can get Servotronic operating on a 135i.

I have managed to get the speed adjustable assistance working in a more meaningful manner than the hit and miss that was previously the case. The weight is the same as without Servotronic in the quarter turn either side of straight ahead but the servo assistance kicks in past there and takes off the additional load as you add the additional three quarters turn. The reason for the additional weight is the amount of caster built into a 135i (approx 7 degrees stock) which means you are actually lifting the car as you are turning the wheel. It is accentuated with mine as I have 8.3 degrees.

The 135i pump is smaller than that on the M3 and 1M and I assume this means that the hydraulic pressure is less and so more human effort is required.

The new steering weight is not as light as a standard 135i and probably heavier than the sports mode on a M3 or 1M, but not un wieldy as with no Servotronic. This only really relates to parking speeds, other than that it is a little lighter up to 30 kph but faster than that feels the same as before the Servotronic function was active.

The next thing is to thank the author of NCS Dummy and the member who
posted a 1M FSW_PSW dump file on this forum. The dump file enabled me look at the difference between the instructions of a 135i and 1M and trace down the ecu other than JBBF which needed to be re coded. NCS Dummy helped find what was required in the Kombi ecu.

What came up was that the following instructions were active on a 1M and inactive on a 135i. I coded them in as active and this settled down the rather on/off Servotronic assistance I previously had. (I was aware that the Servotronic function was working after I had coded in the option as when I disconnected the wiring I would get a fault come up and there was a current running to the valve but it fluctuated wildly).

ST_MDRV_ALIVE_MONITOR
aktiv
ST_MDRV_CSUM_MONITOR
aktiv
ST_MDRV_ID_MONITOR
aktiv

So there you have it, add the option $216, recode the whole car, alter JBBF to Servotronic aktiv and make the changes to the kombi ecu as above.

It is not as assisted as a 1M but it is a lot better than none at all.

There are a host of ST_ and other instructions in the JBBF ecu which are steering related and they are the same between a 135i and a 1M. These may adjust the level of assistance but I am not sure I want to tamper to much with these. They may only relate to activ steering or electric steering. I am happy with the way it is.

I am not going to put in a big warning about doing this at your risk as I have found the ecus' to be remarkably resilient to cock ups. These are only minor changes and I also found that NCS Expert will not allow you to make alterations to instructions that are not reasonable.
 
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doublespaces

Administrator
Oct 18, 2016
7,609
AZ
You missed this image and the procedure:DShamelessly copied and pasted from http://www.1addicts.com/forums/showthread.php?t=1137304&page=3

Thing is...where did this diagram come from? M3 is controlled by DME and 1M has an Active Steering Controller..
I'm reading your build thread post and I think this is a home made diagram, with our junction box in mind(They did the work).

I'm pretty sure you could wire it up exactly as they state. If you could find the names of those connectors on the fusebox and take some photos, that would be great for me to follow later this week.
 

AzNdevil

Corporal
Nov 4, 2016
234
Hong Kong
I'm reading your build thread post and I think this is a home made diagram, with our junction box in mind(They did the work).

I'm pretty sure you could wire it up exactly as they state. If you could find the names of those connectors on the fusebox and take some photos, that would be great for me to follow later this week.
actually...its not a homemade diagram...its from ista for "something" if i search under M3

a4010a.jpg

Interesting thing is...
a4010a_pinout.jpg


Location of x14270
x14270_a.jpg

And this is how it should look like...
x14270_b.jpg
 

doublespaces

Administrator
Oct 18, 2016
7,609
AZ
That is very peculiar... So let me get this straight, this diagram depicts it incorrectly for the car its designed for, and correctly for our very rare use case?
 

AzNdevil

Corporal
Nov 4, 2016
234
Hong Kong
your guess is as good as mine...
the 1/3 series non M and 1M has its own active steering control unit to send out the signals
the M3 sends the signals using the DME

so what exactly is this for is unknown.... but if they say it works...

i have ordered the M3 harness, the bushing contact with the wire for the junction box plug and some 20awg wires that should arrive in a week or two...we shall see....
 

doublespaces

Administrator
Oct 18, 2016
7,609
AZ
I would have to look, but is X14270 considered the 'rear plug'? And pin 5....Wouldn't this all depend on how your fusebox is setup? Because I'm pretty sure there are a few different revisions of the fusebox on the car models.
 

doublespaces

Administrator
Oct 18, 2016
7,609
AZ
well from the 1addict post...the pin out is for jbbf2
but i dont know which jbbf i am running ;)
I have not looked very hard, but how did you remove the steering rack? I've got mine unbolted from the subframe(removing turbos)

And at this point I figure I need to drain the power steering fluid and disconnect it from the steering column somehow? Are there any instructions on this? I have a Bentley but have yet to look for this in it.
 

AzNdevil

Corporal
Nov 4, 2016
234
Hong Kong
I have not looked very hard, but how did you remove the steering rack? I've got mine unbolted from the subframe(removing turbos)

And at this point I figure I need to drain the power steering fluid and disconnect it from the steering column somehow? Are there any instructions on this? I have a Bentley but have yet to look for this in it.
umm.... rough procedure...
center steering wheel
loosen inner tie rods on one side (the side away from the steering input column)
ball joints out on both sides, take off inner + outer tie rod
remove heat shield
remove ps hoses from steering input column, it will leak all over the subframe and onto the ground
release pinch bolt from steering column
loosen rack bolts, slide rack out

i guess you could drain most of the ps fluid out first if you remove the return hose on the rack

btw alignment will be way off (undrivable) even if you install your old tie rods or use measurements from your old tie rods so make sure you have a way to make the car go straight and get an alignment afterwards

also..you should consider installing a ps cooler as well because ive noticed more oil coming out of the ps reservoir after the rack install...and i havent really driven my car hard but this of course you need a different set of lines, and you may consider doing the 1M reservoir upgrade like the M3 guys do at the same time as its supposed to be somewhat better at venting excessive pressures

if i remember correctly, you will need 2-3 lines extra to hook up the PS cooler but good luck getting all the lines to fit and i have no idea where the PS cooler goes...in stock configuration, i think it is supposed to be where our intercooler sits
 
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