S-Prihadi

The post here willl explain what I meant : Post #5 and #6
https://mbworld.org/forums/e-class-w...ml#post8467416

I think the program was originally for a Y77/1 transducer from other engine/s which need more force to close the wastegate or from different supplier and has different characteristic of the solenoid. M276 3.0TT and M278 call this device a Y77/1
Y77/1 if I google, usually I get MB diesel engine . https://mbworld.org/forums/mercedes-...als-fault.html


I shall update this thread when and if I found other issues.

I am planning to chase the VVT ( variable timing ), some of the data presented by Xentry does not make sense.

Senecat

You're like, a Mercedes detective. Is this your full-time job?

S-Prihadi

I would like to make sure my scan/diagnostic tool won't screw me up.
I don't trust scan tool a 100% too anyway, hence I done the duty cyle confirmation and it bring rewards, I just educated myself and my friends at MB forum

Something else.
Xentry is very information stingy and has errors too in its guided test. WIS is also quite information stingy when it comes to explanation of component level workings 101.
I think there is another real classroom education for authorized MB technician by MB HQ, this way they can keep their know-how to smaller active in-house group.

See below :


The above information for guided test is garbage : MUST BE 11 - to 14 volts ( battery voltage without and with charger) Ignition ON, engine OFF
The power sent out by the ECM ( and fuse #22 ) to the 2 wires Y31/5 ( Y77/1) is a PMW signal square wave and not a simple full analog voltage.
During ignition ON-Engine OFF, one will not get even 11 volts from a good charged battery, it will be 9ish volts. 9ish volts because regular DMM voltage reading can't read PMW true voltage and will average it.





Only a scope can read as 12ish volt. I set scope capture memory/sampling too small at 16Ks, so the square waves don't look nice.... LOL

Xentry did not mention to measure using a SCOPE, so DMM is then the default choice.



.



What happen to a newbie techie who does not know about PMW ( duty cycle ) ? Declare high resistance and start messing around with engine wire harness ? .... as per Xentry guided test


I looked at the solenoid manufacturer data sheet. Pierburg.


Yes, 11.4 ohms is what I get. Many official repair manuals I had in the 90s to early 2000s has Ohms data for sensors/motors/etc where applicable.
See the 300Hz information, that is why I also try to verify for the 2nd time with a Fluke DMM and the Picoscope too.







Now I know the complete operational parameters of the boost transducer solenoid.
A good time to learn or collect database is when we have a known good aka engine/system is still healthy.

With so many duty cycle operated components in our cars, example the GDI high pressure fuel pump metering valve, if one day say my ECM went a little banana not on the duty cycle output
but at the frequency output.... say it goes too low Hz and causing less precision control somehow.... such an issue is a nightmare to troubleshoot if I do not know the frequency & duty cycle assigned for it.

If one likes to read on solenoid duty cycle and effects of the assigned frequency, this is quite a good one : https://www.researchgate.net/publica...75986/download


It all started actually due to my desire to learn more of my car and while using Xentry and the Pico scope, then I spot the whacky side of Xentry
Plus, my itchy fingers need to do something ...always.

.

Senecat

It's good to have you around, Prihadi

You're into stuff that's way above my pay-grade, but it's interesting/educational nonetheless. Much appreciation for what you do and contribute!

CaliBenzDriver

Master Surya:
You've opened another very interesting can of worms in your relentless quest for performance.

When you mentioned replacing your TT control valve... I thought hopefully this problem is not caused by a flakey up signal... you know.
- Now there you are scoping that line to double check it.
👍


DVM are last century tools! They can not read high frequency voltages, only DC and 50/60Hz sinewaves.
When you ...:

• set your input trace over the zero value
• with "DC coupling" selected
• short out the lead to GND for calibration
• ​​​​​​Then you can read the min and max values of your signal.

floating traces

Right now it's a bit all over. You need to be able to trust the 12v trace is at 12volt DC.


good references settings = trusted useful values

That being said , always make sure the min and max values are near where you expect them to be: near GND reference and ALT voltage +/-0.5VDC

Thank you for leaving no stones unturned.
👏

S-Prihadi

Yes Cali I notice the "ground" is not zero volt for the square wave ( Blue channel A )

This ground is the signal of the ECM to the solenoid not chassis or battery ground. This is a 2 pin solenoid.
I think being an inductive coil the solenoid is, the -0.81V might come from the coil's back EMF.
Below is how I connected the blue channel A to the solenoid.



It is also a monitoredground ( ECM pin 31 ) and when that 2 pin connector removed from solenoid, ECM will flag it as DTC.


I did not use Pico suggested connection method, where the scope negative goes to chassis/battery ground.
I am adding the pico link : https://www.picoauto.com/library/aut...olenoid-valve/



High Res image :

I also have to learn more of how ECM uses bias voltage to monitor status of sensors. Some cars I read can be 2ish volts , some can be much lower at 0.45V
https://www.techtips.ie/Autobiz/unde...or-sensors.pdf

CaliBenzDriver

[QUOTE=S-Prihadi;8489110]Yes Cali I notice the "ground" is not zero volt for the square wave ( Blue channel A )

This ground is the signal of the ECM to the solenoid not chassis or battery ground. This is a 2 pin solenoid.
I think being an inductive coil the solenoid is, the -0.81V might come from the coil's back EMF.
Below is how I connected the blue channel A to the solenoid.



I did not use Pico suggested connection method, where the scope negative goes to chassis/battery ground.




/QUOTE]

Shared Reference to... circuit vs. GND!
Very well so long you keep in mind the scope reference input is shared amongs all inputs. You can set it were you want.
When set to Ref GND, you can not see solenoid ECM lead unless you use a 2nd channel or check it once and switch input to scope other circuit side.


Computer saver...:
I like the way you have it connected using only one channel on both sides of solenoid but then you can not use other channels because scope Ref/GND is already hooked to ECM solenoid pin.

Try to always keep that detail in mind... I remember blowing up a x10 probe to learn that!
My scope GND is directly connected to the 120/220VAC GND pin.
Pico likely ties its GND to the laptop USB GND and in turn, GND is referenced through the AC power cube or USB Hub extension supply... beware when you have a 40Amp var power supply hooked up what the BATT(-)/GND gets referenced to vs. your Pico probe GND.
. .

kajtek1

I always admire people's devotion to hobbies, what seems to be on decline in USA. Sad part of life that better wealth kills devotions and family ties.
Still remember when Turkish member made pictorial how to repair $50 core temperature sensor with 30 cents thermistor.
The above is above my paygrade as well. Even I learned to deal with scanners and spend money on Chinees SD hack one time, I could not make it working.
Fellow MB owner bought better version, but not being software inclined like I am, he had to ask for lot of help from SD guru we met on other forum. Than when I needed help with resetting transmission code, his SD clone could not find it. Finally master key code clearing did the trick, but the experience is steering me away from spending time & money on buying the stuff.
My MB run good for last 2 years (knock on the wood) and Bluetecs afer AEM do have 4 years warranty on most of engine parts, what sure is big relief.
You guys have fun.

S-Prihadi

Yes Cali, the baby low cost 2 channel 2205A pico scope SHARED ground is the danger zone. my fear no 1.
That is why I also bought the automotive one 4 channel Pico 4425A because it is floating ground, I think max 30V though. My bad luck, it arrived and 4th channel had a cold solder joint/bad contact...DAMN !!!
I am discussing with AESwave on how to fast warranty claim it, while a friend of mine is till in USA till 16th Jan and is then coming back to Jakarta and is able to carry home a new 4425A.

From Pico on the 4425A automotive variant :
Independent floating inputs
A major innovation on these new scopes are the independent floating inputs; think of it as 4 separate 1-channel oscilloscopes in a box all sharing the same timebase and control.
This means that all inputs can be used in differential mode (e.g. CAN High and CAN Low signals), or across non-grounded components such as 12 V injectors,
or for voltage drop testing using a single input (maximum 30 V common mode voltage difference between channel grounds).
=====================

You are right on the :
Pico likely ties its GND to the laptop USB GND and in turn, GND is referenced through the AC power cube or USB Hub extension supply... beware when you have a 40Amp var power supply hooked up what the BATT(-)/GND gets referenced to vs. your Pico probe GND.

I once got a DTC because I was using Xentry Pass thru which uses USB to the clone Tactrix dongle and Pico being a PC based also uses the USB. My baby low cost Pico 2205A is a common ground unit.
Since this turbo boost solenoid is ground switched by ECM, I am sure the Tactrix dongle connected to OBD2 port and also USB, shares the common car chassis/battery ground from the OBD2.
So the ECM detected a "short" on the turbo boost solenoid...LOL. Solution was to use the Autel MS906BT because it is wireless blue-tooth at the OBD2.

Yes, I did take the pre-caution to not use the AC power supply/charger of my laptop when doing the solenoid test, as you cautioned .... my power maintainer for the car is a 33amps power supply and
I dont want my laptop to share car's ground too via the power maintainer. So i also did not connect my 33amps power maintainer to car battery during actual test.
This 33amps power maintainer is not super clean anyway, 200 millivolts ripple at 15 amps load if I remember correctly. This 33amps unit comes from my drone days.
These two power supplies I am sure are switching ones, so no true isolation transformer used.

S-Prihadi

K,
I am a confirmed IT stupid, I feel it is a strong lacking in today's era with so much computer control in our cars and daily life.
Initially I wanted to buy the Chinees SD hack/clone and locally a ready to use unit with old gen suitable laptop included , will cost me US$2K and 1 year warranty.
Instead I choose the dumb down Xentry pass-thru version ( much cheaper too ) as I want to avoid any potential mistake a more powerful/able Chinees SD hack/clone can do.
Next choice is the Autel MS906BT which cost US$1,500ish locally , 1 year warranty and 2 years free all available car models software updates . I have to have a proper 2nd scanner, as 2nd opinion so to speak.
It so happened the MS906BT being a blue-tooth based OBD2 dongle, it is a good thing for ground isolation towards my Laptop when I am scoping using a non floating ground baby pico 2205A.

Language is another barrier for me, I mean technical English language. Xentry is originally a German program and I think some of its translation to English is too literal and with my dumb IT know how, it is a risk.
I don't need to modify my car in anyway super duper, all I want to know is how it actually works in the electronic or signal side of things. So I am happy with the naughty Xentry pass-thru and I hope when the
original Tactrix OBD2 dongle arrives, it can do better in terms of speed and certain communication issue I have for M271DE2.0 engine computers found on M271.860 EVO engine of C200/E200 - C250/E250.

kajtek1

Translations are another subject. Typical is "pilot bushing" - common part on 5G transmission who can be never understood by English-speaking mechanics. . We had a topic about it and concluded that manuals had to be translated by engineer's WIFE as supplemental income for the family.
I learned some German and it does have unique logics. For example "26" in spoken language translate to " six and twenty"