Mercedes-Benz Forum banner

Ready to turn the ignition key, is there a learning procedure for the ECUs?

5K views 27 replies 7 participants last post by  MAVA 
#1 · (Edited)
Gentlemen:

Next week, if all goes well this weekend, I should be able to finally start the engine after my approx. 18 months-long project.
Cannot wait to hear it running

Work done:
- Top/front of the engine were taken apart and put back together (M120.980).
- I've repaired the harness to the ECU box, so, all modules were completely removed from the car.
- Transmission (722.3) was also rebuild.

Before I put the battery in the trunk and try the ignition key, is there a procedure to follow for the ECUs to re-learn their functions?
How about initialization of the ETAs?
Anything else I need to do before the car rolls out of the garage for a test drive?

Many thanks,
Steve
 
#3 · (Edited)
#4 ·
actually i do not know details. i can just guess that relearning of ETA is ok for every W140. This is my impression based on how people describe re-learning procedure. i might be wrong but if so then descriptions are not accurate i dare to say.

transmission will relearn itself. just drive the car as you drive it.

i do not know almost anything about re-indexing of steering. I think you can trust to Chris's thread :). once i just read about it somewhere and basically it is moving steering wheel from both extreme positions several times .... slowly with engine on of course. i cannot imagine that it is critical procedure but as i wrote, I haven't used it in practice. good luck !

Samo
 
#5 · (Edited)
actually i do not know details. i can just guess that relearning of ETA is ok for every W140. This is my impression based on how people describe re-learning procedure. i might be wrong but if so then descriptions are not accurate i dare to say.

transmission will relearn itself. just drive the car as you drive it.

Samo
Hi Samo:
The way I see it, there has to be a difference between the cars with the throttle cable and the ones with the fully electronic actuation.
Does anyone know for certain?
Steve
PS My transmission is not electronically controlled, so, no re-learning. The new parts just have to 'settle in'
 
#6 ·
Steve_B, The ETA reset that Samosali sent was the same one that BBA sent me when they rebuilt my ETA from a '94 CE320. It did the trick. However, don't you have two ETA's? If you are concerned, I would contact BBA Remanufacturing in the Boston area and tell them you want to send in two for rebuild and how do you reset two of them? And somewhere I have a procedure (from MAVA) for "resetting" the transmission. I'll post it when I find it.
Anziani
 
#10 · (Edited)
Yes, there are two ETAs. But this is not the point.
The car is not ready for a road test yet. I just want to start the engine and check for leaks/noises.

In any case, taking the car on a drive for a variety of driving conditions and operating it at least once or twice over 65 MPH reminds of the "setting the readiness" procedure for the OBD II.

And yes, the 722.362 is the MB 4-speed transmission that has NO computer.

Steve
 
#7 ·
Hi Samo:
The way I see it, there has to be a difference between the cars with the throttle cable and the ones with the fully electronic actuation.
Does anyone know for certain?
Steve
PS My transmission is not electronically controlled, so, no re-learning. The new parts just have to 'settle in'
hmmm, i am really not an expert however I do not see why throttle cable/fully electronic actuation would affect the relearning procedure. It is just my guess. I see relearning only as a procedure where end switches in the throttle actuator body are recognized and memorized as references by the system. With end switches i mean fully opened throttle, idle throttle and fully closed throttle. Something like that, i think I am not far away from truth even if my explanation is not 100% correct.

I cannot comment anything about your transmission. This part of car is really not close to me. I am surprised that your transmission is not electronically controlled but my knowledge about this area is really low so I must be quiet :). I hope others like anziani will be able to help you.
 
#9 · (Edited)
hmmm, i am really not an expert however I do not see why throttle cable/fully electronic actuation would affect the relearning procedure. It is just my guess. I see relearning only as a procedure where end switches in the throttle actuator body are recognized and memorized as references by the system. With end switches i mean fully opened throttle, idle throttle and fully closed throttle. Something like that, i think I am not far away from truth even if my explanation is not 100% correct.
The older system is fairly low tech by today's standards.
The cable operates one of the actuators manually, the other is synched.

The distributor-less system (which also happens to be introduced together with the OBD II protocol) has the drive by wire set-up, where the driver's right foot is just connected to the ecu that monitors where the accelerator pedal is in its travel. I'd argue that the two are not likely to be initialized the same way.

Steve
 
#8 ·
Depending on if your car has ASR or not, there will be differences in the throttle body itself.

My coupe has ASR but still has a throttle linkage despite it being considered electronic.

The manuals I have mention that if you have replaced the control unit for the EAs (N4/1, with ASR) then the manuals say that the ignition must be turned on for 90 seconds (without starting the engine). The synchronization between the control unit and the electronic accelerators takes place during this period. I'd imagine you'd hear the EAs buzz and maybe click around.
 
#11 · (Edited)
Depending on if your car has ASR or not, there will be differences in the throttle body itself.

My coupe has ASR but still has a throttle linkage despite it being considered electronic.

The manuals I have mention that if you have replaced the control unit for the EAs (N4/1, with ASR) then the manuals say that the ignition must be turned on for 90 seconds (without starting the engine). The synchronization between the control unit and the electronic accelerators takes place during this period. I'd imagine you'd hear the EAs buzz and maybe click around.
The 600SEC has ASR, standard.
The throttles are electronic (ETAs), of course.

What you describe is fairly typical for the drive-by-wire set up. My wife has an Audi A8, where if the battery is disconnected (or the throttle body removed for cleaning), an "adaption" of the very same nature must be performed before cranking.

Which leads me back to the same question I asked at the beginning -- does anyone know (with certainty) if there is a learning/adaptation procedure for the early M120?

Thank you all for the discussion so far.

Steve
 
#12 ·
Steve, the link you posted on previous page where I commented about how to reset the Throttle Actuators is the correct procedure to do a complete Reset for those .
On your early SEC M120 ,it is exactly the same like on mine , I have done the Reset many times & every single time the engine revs up to about 1500/2000rpm's then slowly settles down back to normal 600rpm's or lower (550) .
Only if you for example swapped engines like I did ,then yes you would need to retune/reprogram the ECU's like engine management or what ever your car has in options added in regards to engine , the transmission like Samo already mentioned ,will relearn by it self with 30/40 transmission shifts ,so if you for example go slow ,the transmission will settle to a normal slow changing behavior but if you for example drive erratically ,then the transmission will adapt to that kind of driving & change faster .
You can experience this by letting the transmission shift by driving normal all day ,then the next day you feel that something is sleeping here ,so as you drive the car harder on that day ,the next day you will find that the car would drive much more like a sports car for example ,the gears shift quicker somehow , to feel the difference it doesn't take a day but more or less li9ke I mentioned 30/40 gear changes ,keep that in mind .

On mine when they changed the engine to one exactly the same M120 ,they still remapped the ECU to that engine & also had to change some electric things I don't know of ,they also changed the Throttle Actuators for some reason from the new engine, they used my original once , you didn't do that so no worries there .:thumbsup:
 
#14 · (Edited)
Steve, the link you posted on previous page where I commented about how to reset the Throttle Actuators is the correct procedure to do a complete Reset for those .
On your early SEC M120 ,it is exactly the same like on mine , I have done the Reset many times & every single time the engine revs up to about 1500/2000rpm's then slowly settles down back to normal 600rpm's or lower (550) .
Only if you for example swapped engines like I did ,then yes you would need to retune/reprogram the ECU's like engine management or what ever your car has in options added in regards to engine , the transmission like Samo already mentioned ,will relearn by it self with 30/40 transmission shifts ,so if you for example go slow ,the transmission will settle to a normal slow changing behavior but if you for example drive erratically ,then the transmission will adapt to that kind of driving & change faster .
You can experience this by letting the transmission shift by driving normal all day ,then the next day you feel that something is sleeping here ,so as you drive the car harder on that day ,the next day you will find that the car would drive much more like a sports car for example ,the gears shift quicker somehow , to feel the difference it doesn't take a day but more or less li9ke I mentioned 30/40 gear changes ,keep that in mind .

On mine when they changed the engine to one exactly the same M120 ,they still remapped the ECU to that engine & also had to change some electric things I don't know of ,they also changed the Throttle Actuators for some reason from the new engine, they used my original once , you didn't do that so no worries there .:thumbsup:
Thank you Chris. Two comments from me in response:

1. We are NOT talking about remapping/reprogramming the chipset. This is done by tuners to squeeze more of their engines (done in conjunction with boring throttles, adding boost, changing valves and/or cams, etc.)

All ECUs with the same part number will work for the applicable engines straight out of the box. Learning/adaption might be needed but the engine should start off the program stored in the ECU memory.
After a drive-cycle, feedback from the O2-sensors, CTS, etc. some 'trimming' will be applied and the baseline modified to a particular engine. This 'trim' should be lost if the power to the ECU is disrupted.

This is my basic understanding of engine management systems of this vintage.
I could be wrong as I have never owned a MB product (the 600SEC is my entry into this world), but I doubt BOSCH supplied them with something that did not exist in the early 1990s.

2. My transmission, and likely yours, is the old-school 722.362.
4-speed. No electronic control. I invite you to visit my thread here:
http://www.benzworld.org/forums/w14...hic-b3-piston-failure-tranny-rebuildable.html

I've had it apart in my basement over the winter. I can assure you (this is not me reading off the internet, this is me with hands-on experience) that this box CANNOT change its habits depending on how you drive.
There is no electronic input (well, the kick-down solenoid is electric, but it gets the signal from the switch on the pedal).

The shifts are vacuum regulated. The infamous Bowden cable is also responsible for how mild/aggressive the shifting is.

I will need to do these adjustments next, but first thing first -- start the engine.

In that regard -- your procedure calls for 90 seconds at WOT with the ignition on.
thisisntchris87 posted the same, or rather nearly same. According to him, the synchronization happens only with the key on.

Which one? WOT or closed throttle?

Many thanks,
Steve
 
#13 ·
The older system is fairly low tech by today's standards.
The cable operates one of the actuators manually, the other is synched.

The distributor-less system (which also happens to be introduced together with the OBD II protocol) has the drive by wire set-up, where the driver's right foot is just connected to the ecu that monitors where the accelerator pedal is in its travel. I'd argue that the two are not likely to be initialized the same way.
yes you are right. My starting point of consideration in my head was actually application of cruise control. In this case I think both types of actuators work in the same way. Is that right (because I am not aware of all details and like i stated i am far away from being an expert for w140 throttle bodies :))? I can feel how the gas pedal moves after increasing the speed with cruise control switch on the steering wheel. my throttle body has a motor inside (i hope you are aware of this fact), so maybe these two systems are actually not different in terms of technical cybernetic which deals with controlling of similar systems. so in both cases we have (i) our aim (certain speed of the car), then (ii) the actuator with some switches and potentiometers inside, we have (iii) feed back (speed sensor), we have (iv) output (real speed of the car), we have (v) input signal (driver's foot or gas pedal). like you said, the difference is in a location of switches, in my system there is no switch at the gas pedal, the switch is in the throttle body instead. So i want to say that i still do not see a significant difference between both systems (cable, drive by wire).

i was thinking about transmission and now i understand your remark about "controlling the transmission". yes of course ... my transmission is also not ecu controlled. i would like to hear a comment if this means that my or your transmission actually do not change their shifting regime so they do not learn from the way we drive them. thanks.
 
#16 · (Edited)
Gents,

Correct me if I am wrong, but for the W140 ETA, there is a calibration procedure not a learning procedure ?
Being not an engineer (and with English not my mother tongue), I asked about 'learning'.
We probably talk about the same thing.

Other terms that may apply:
1. Initialization
2. Adaptation
3. Calibration
4. Synchronization
 
#18 · (Edited)
Here we go,

Indeed there is 722.6 option for your S65.

See the pictures.
I will strongly encourage you to read the posts in this thread carefully prior to responding and going off-topic.

For the record, and yet again, this is the w140 forum.
The car in question is a 1993 600SEC (the only year the 140 coupes came out with this designation).
The engine is the M120.980
The transmission is 722.362
 
#19 ·
I've had it apart in my basement over the winter. I can assure you (this is not me reading off the internet, this is me with hands-on experience) that this box CANNOT change its habits depending on how you drive.
There is no electronic input (well, the kick-down solenoid is electric, but it gets the signal from the switch on the pedal).

thanks. I've got my answer.
as for learning or calibration of ETAs I think there is actually no need to do it because it (they) will do it on its own over time - this is also from practice not from internet :).
 
#21 ·
Steve, I would go ahead and start it if you are not going to drive it. We started the CE320 a couple of times before we drove it. Here is the transmission reset. I think it came from MAVA. If you are not going to drive the car yet, I wouldn't worry about this.

Turn key to the "on" position (right before you start the engine.
Turn(?) and hold the gas pedal down for 5 seconds.
Turn the key to "off", then release the gas pedal.
Wait 2 minutes.
Then drive car normally.

Anziani
 
#22 ·
Steve,

Get your eta squared away first, if you are dealing with the steering too and priming of the powere steering pump. Then raise the front of the car in the center, so both wheels are up( no weight on them) turn the steering wheel to left and to the right, but do not bang each end, bu wait a second or two at each end, and do it about ten times.

The transmission, their are no adaptations to deal with, or set up procedure. It will just get smoother over the next few thousand miles.
Now, most of the times they start shifting really late - do not worry about this. If you have to let of the throttle pedal to shift gears - no worries either It is important you get all the gears. Now, if you driving along and it shifts to nuetral after a gear( which will be probably third gear) You "F'ed up "inside the tranny, so what may have happened is you either crushed the two teflon seals at the back , or your governor stripped a gear, oorrrr sheared the pin to lock that gear in. If your 2-3 shift is short the dog bone pin is eather to short or too long, so the B2 piston will have to come off.

When you start every thing. The car will smoke like crazy in the engine bay. Just get on your hands and knees, look for sustained leaks. Watch your temperature and oil pressure. If you can prime your car with oil by disconnecting the fuel pump fuse and crank the engine for 30 seconds to avoid the knocking on a cold start up as the car has not had any kind of oil flow in it. These old trannies like to leak at the dip stick o-ring at the bottom, so have a strong flash light. I suggest you start the car on a shaded or overcast day only, so your vision stays acutely sensitive to the same light outside the car as under the car, so it is not adjusting from high contrast to low contrast as the result of a bright car.

All the best

Martin
 
#23 · (Edited)
Thanks Martin. Your detailed and to-the-point response, as always, is much appreciated.

Engine was cranked for over a minute with no spark plugs, I verified that oil flows and all is good in this Department.
Drained the old fuel and have fresh premium too. Fuel line purged and pressurized.

Transmission and steering/suspension are second and third on the waitlist.
I need to check for coolant/oil/transmission fluid leaks before I continue with the disassembly. Not to mention that I rebuild all harness wire by wire and I am 99.99% certain all wires go to the correct places. But that is 99.99% and not 100%, which also needs to be checked on the to-do list.

To sum this thread up, the prevailing opinion is to just start it and see what happens.

Steve
 
#24 ·
To sum this thread up, the prevailing opinion is to just start it and see what happens.
I strongly support this approach. those re-adaptation and re-learning procedures are mildly said questionable in my mind. namely, you found out on your own that it is not about reprogramming a chip inside the management computer. So whatever it is, if not this, it cannot be crucial. I read some articles written by people who left impression that they know what they are talking about, that best relearning method is time&drive. I can upload this article here if there will be a wish, it is about adaptation (fuel and air) procedure in our cars. Secondly, when I mounted my remanufactured ETA (at BBA reman) I was lucky and got comment by forum member Bayhas; he also suggested that time will make everything what ETA needs. In my opinion Bayhas has a lot of knowledge about w140s. Once again, conclusion is that you cannot do a crucial mistake if you neglect so called relearning method. Even if it is a mistake it is not irreversible.
 
#27 · (Edited)
I would not worry about the SRS light....You can deal with it later. My buddies S600 Coupe has had it for three or four years on... I drove with it on for about few months too..

Martin
Thanks Martin.
I will take your word on that, although Mercedes Mechanix (you are familiar with this member, aren't you/) advises to take it seriously.

http://www.benzworld.org/forums/w140-s-class/1387600-srs-light-going.html

I would at least like to know what causes the light. Don't want the airbag to knock me out while trying to get it going...
Steve
 
#28 ·
Steve,

Yea, the bags may not deploy, Then take it seriously... I'm just telling you what has occurred in my circle.

Yea Yea Yea....engineers want to know everything.....I'm engineer too. I just go with the flow of things...

Reset it with Star, and see what happens... My buddies case he just un plugged the air bag with the battery connected...Dumb, yes... We both have just not reset it-We forget..

You are wearing the pants you decide?

Martin
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top