JettaRed

iTrader: (1)

And this on AliExpress if you want to wait. Far cheaper than the CPS pigtails. You can shop around.



https://www.aliexpress.us/item/32568...21877770170%21

JettaRed

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@kevm14 I was able to find the same screens in XENTRY. However, the test procedures don't help understand how the sensor is used. I wonder if the logic that uses the pressure sensor causes the CEL (which should only be emissions related) to illuminate when the solenoid is absent from the circuit.

zk2004mb

Thanks folks! I'll be out of town for next week.

Will buy a cheap knock off solenoid and test when I'm back
Happy new year!

CaliBenzDriver

That's fantastic research material

-- Where we at is that we are suspecting the ECU could be flagging the optional oil pressure sensor as a sort of "unexpected pressure" condition.

-- Such as:
- ECU commands pump solenoid idle pressure.
- Sensor reads normal pressure.
- ECU flag this as sensor discrepancy fault.

It gets more complicated because if the ECU is scrutinizing actual pressure it will expect variations acording to solenoid.
We can't just set a fixed dummy pressure resistor, it has to track up/down.


> 1+1 = Eureka ??
We already were thinking about a relay coil as dummy solenoid, right?

Now, use actual relay contacts to switch between set pressure sensor decoy resistors!!
​​​​​​
Perfect??
Let measure two pressure sensor values in Ohms:
1- Low pressure: .....
2- Normal pressure: ....

These will be the basis for switched values.
We use paralleled resistors so when relay togles there is no open gap.

-- A high R. value gets a low R. value paralleled by switching so it is seemless!

To every problem its solution!

kevm14

P06DA isn't even a code that will bring up advanced code setting criteria. It's just not in the last of codes to examine. Since it is the same code with or without an oil pressure sensor, I would wager that the oil pressure sensor is not used as part of the routine. Additional evidence for that is I believe OP said his CEL sets immediately upon engine restart, just like applications that do not have an oil pressure sensor. If it were using the oil pressure sensor I'd think it would take at least a few seconds (or minutes) to finally determine that the feedback it is expecting is not present.

Still, that doesn't explain the CEL.

Xentry will tell you when a code sets the CEL or not by an icon. I will dig back into that and compare to my E63 in simulation mode .

JettaRed

iTrader: (1)

We've got two very similar threads going at this point; this one and one in the W212 AMG forum, https://mbworld.org/forums/w212-amg/...enoids-28.html

Post #698, @jcarsnz states, "Confirming my W166 (2015 ML63) does not throw a CEL with plug disconnected.. also, no oil pressure sender." So it would seem that the CEL appears only on cars with the factory oil pressure sensor installed and connected to the ECU (N3/10). I wonder what code appears if disconnecting the oil pressure sensor (B42).

CaliBenzDriver

We split the threads to try understand the specifics of CEL cars and how to deal with the elusive pressure sensor.

It seemed there was a direct link between having a pressure sensor and triggering CEL upon unexpected normal pressure.

Now things are getting mixed up.... unclear does not help solve anything, you know like the SA desk....

The whole exercise is to FIGURE WHAT TRIGGERS THE CEL so we can make good for the ECU.

-A- we can fake dummy solenoid load
-B- we can fake target pressure with dummy sensor
Both solutions are similar +/- 50¢ resistors

If dummy solenoid is not enough on car with pressure sensor then we wire the pressure dummy circuit to existing dummy solenoid relay.


> THE MEAT:
Now we come to the interesting part of things we don't know!

- What does the ECU computes using the real pressure sensor??

- I don't think they have a true pressure regulation with sensor feedback

- We interested to understand any embrio of logic there have built around sensor to fake sensor appropriately.

-- is sensor for attractive display only: possible!
Possible because few cars share this firmware so we know it's super skinny cheap.

Two ways of dealing with CEL/Sensor:
1- We can say "don't worry, it may be the same".
or
2- We can say "we don't know let's find out what's involved".

???

S-Prihadi

Speaking from marine engine :
In older engines , very analog one, sometime they use an oil pressure switch and oil pressure sender...BOTH.
The oil pressure switch is spring type , simple one ..rated at low value 'X" psi to trigger.
Hence on older engines where you can see oil pressure warning light + buzzer, that light and buzzer will sound a few seconds after engine start and then goes away
as oil pressure build up. The buzzer is no joke, it is loud. Sometimes a boat builder will use those bell like school bell type...very loud, so that over roaring loud engines and strong wind,
we still can hear the alarm.

The oil pressure sender back then is more visual info for driver/captain only, and does not offer any intervention mechanism to engine control...heck there was no engine computer back then,
our eyes and brain is the computer...LOL.

I remember gasoline engine inboard racing boats using analog round dial gauges on purpose will install all their gauges as such when in proper operating parameter, the needle is at 12 o'clock.
So the driver and/or co-pilot at a fast glance does not need to see values on the gauges, but a fast sweep of which needles were not at 12 o'clock...smart actually.

Later on in like 1995, Detroit diesel started using "advance" electronic controls on their jurassic 2 stroke diesels, they call it DDEC. Detroit Diesel Electronic control.
I got their gen-1 engine in 1995, a V6 one at 625HP.
In their literature, they wrote about dynamic engine oil pressure alarm trigger setting.
The engineer will define what is the minimum engine oil pressure for this engine at various RPM, as to detect earlier engine oil pressure loss when at crusing RPM which is 1,900 to 2,100 RPM.
This is a 2,300 RPM max engine. Idling is 600RPM.
I really like the idea of engine oil pressure warning being dynamic or RPM based, can save us lots of $$ and trouble.

======

Back to our cars....
So, if a M157 using a B42 engine oil pressure, it could possibly be using dynamic engine oil pressure warning setting...maybe. I would do that if I were the MB engineer in charge.
Or, if the engineering is lazy, they may use that B42 sensor simply as an oil pressure SWITCH equivalent.

Either way, the ECM needs to see a "pressure value" from the B42, or else it will trigger the CEL.

It is SO FREAKIN' stupid this Xentry page



Engine OFF ignition ON and engine oil pressure if read higher than 0.1 BAR/ 1.45PSI, that meant a stuck or drifted oil pressure sensor already...hahaha.
It should be near zero BAR/PSI when engine is off and been off for simply a few minutes. How can up to 1.5 BAR allowed ???

This is not the first time though for me to see Xentry specified value which does not make very much sense.
Some value can be shown with RED color like its bad, but actually it is not bad....it is normal.
Case to note is M276.820 3.0 Turbo turbo boost solenoid PWM/duty cycle signal in %.

If anyone need to do dummy load for oil solenoid, you can also use my method, the 2 x 3 watts bulb with diversion switch to bring it back to normal state when needed.
I go this route to maintain operational "visibility", as such from bulb brigthness I know when and if the ECM was commanding oil solenoid at OFF 10% or ON 50-90% duty cycle.


===========================

ZK wrote:
Based on my experience, disconnecting the solenoid does help at the lower RPM. The throttle response at 800-1500 rpm is much better. The power comes more directly. I usually have a little hesitation around 1200rpm, just feels like the gas paddle is mushy, but now it's gone.

Looking at ZK M157 engine torque, no wonder he can feel its poor "response" under 1,200 RPM if the oil solenoid is plugged IN as is.
https://mbworld.org/forums/attachmen...matic-m157.pdf




.
I wonder what is the torque between 900-1200 RPM ?
I mean 900-1200 RPM is pure VVT territory for response benefit and decent oil pressure is gold for this low RPM operation of VVTs.
Less waiting of VVT to function to its best.... is the actual benefit felt as faster response.

If anyone here is intimate with carburator days and is a throttle heavy person, did you guys remember that we actually loose engine reponse if we open throttle too big too fast
at certain lower RPM. We benefit from modulating the thrrottle to be just right...it was the fun art back then.

Some of you probably know that BMW engine does not use throttle body to control air into engine .... it uses its VVT / VANOS.

Using electric motor as the prime mover of the air intake system of the BMW as explained in the video, it does not need much waiting time like our oil/hydraulic based VVT.


So anytime our VVT can be made more ready at low RPM, we benefit from a less delayed response.
Even say MB engineers uses throttle pedal commanded opening ( our foot ) if above "X" value...........to increase the oil pressure before 3,500RPM , there will be delay in the actual increased hydraulic flow to arrive
at the VVT :
Oil pump>>>oil filter>>>oil cooler>>>oil gallery>> furthest away VVT sprockets would be Bank 1.


What Cali explained in many post about give the engine time to do its adaptation for the abundant* oil pressure ( *oil solenoid defated ) at low RPM, that is very correct.
My engine I were on a long run Jakarta-Bali-Jakarta, the first few hours the car coming back to Jakarta super bad traffic jam, even in E mode it felt overly agressive
for extreme snail pace creeping traffic which my engine would not experience the past 2,500KM long distance trip. Of couse by some hours later the engine would
adapt again to Jakarta miserable traffic jam.

Since ECM is the King of driveability decision making, the VVT decent oil pressure goodness can be felt all the way to tranny reponse, more so at fine modulation low RPM where
it is tough to accurately modulate with beauty and precision from 7th gear to 3rd gear when car at under 50MPH or under 80KM/H. I mean using our foot to drop to 6-5-4th gear of your choosing is
not so easy when and if VVT is not fast responding. Kickdown for lowest gear is and has been easy of course, may not be the fastest in terms of milliseconds but do-able at all time.

Tranny can't shift gear without ECM authorization, that is a fact.
So I think this higher oil pressure or better word is NORMAL OIL PRESSURE.... from no-more manipulation by oil solenoid..at lower RPM simply made your engine more ready and hence
allows you to get its response a tiny bit faster. There is no horsepower gain, just less lag or delay, at lower RPM.

Again it is up to the engine owner to decide if he/she wants the oil solenoid to be defeated or not.

S-Prihadi

Dang... I forgot to ask ZK.
Having an oil pressure sensor B42 from MB as standard, does the instrument cluster or ECM PIDs show an oil pressure value ?
As fas as I know, OBD2 official PIDs does not even include engine oil pressure.

JettaRed

iTrader: (1)

Makes me think that the corporate lawyers are telling the engineers to squeeze out just a little more MPG, even if drivability needs to suffer. Is the lag unacceptable in a 5-speed tranny? Well, build a 7-speed tranny. Is it still unacceptable in a 7-speed? Build a 9-speed. And, along the way, give the driver options for how the tranny shifts because we will measure our fleet fuel economy based on impotent E/C settings. Give them S or S+ because those fuel numbers don't matter. Add something stupid like Eco Start/Stop even though the engine will suffer and drivers will be scared to death to pull out in traffic or across a cross-road--they'll become a more careful driver and the planet will become a better place. And when it is finally discovered what we have done, meh! Don't worry because we will have gone total EV by the time it makes an impact on sales. And don't worry about those few crackpots over on MBWorld. What do they know?

So, folks, here we are. For me, I'm old and I want to spend my last few driving years ENJOYING my car!

kevm14

More digging in Xentry.

I have additional observations. First, you cannot use Xentry Simulation to determine if a code should trigger the CEL. That is part of the actual code in the ECU. Rather, in Simulation mode, you get to manually choose whether to flag a code as "turn on CEL" which is the opposite of what I wanted. I fiddled around with it and it didn't tell me anything more interesting.

I also searched again for a way to modify the value of the B42 oil pressure sensor. It is simply not there. I cannot even input a value in all of the stimulation parameters. I guess this checks because the codes (along with the original 06DA) have no advanced diagnostic info. The check of B42 is accessed directly, not recommended as a test due to a code.

I did, however, dig further into the test for the oil pressure as well as oil pressure related codes. NONE of these codes are in the list for detailed diagnostic information.



Just wanted to highlight that activation is supposed to make a click sound. I guessed that originally but it's written in Xentry below.


Zero oil pressure should have a nominal sensor voltage of 5V (I assume almost open circuit). I also assume that if you checked resistance across the signal pins, it should be very high (engine off).


This is the second oil pressure sensor diagnostic screen that I found. 2.5 bar @ 2500-3500 is what they want.


I still see no evidence that the oil pressure sensor is somehow involved in the CEL. I don't think I understand what makes a 06DA emissions related on a car with the oil pressure sensor but not emissions related on a car without it (most of them).

Perhaps the proof of this would be to install a dummy load (or another solenoid) on the oil pump solenoid plug and see what it does. If my theory is correct, there will be no CEL, because I don't think it is using the oil pressure sensor to determine anything here. It doesn't even have an "oil pressure too high" code to set (which is a possible condition when the solenoid should be activated and dumping pressure but oil pressure is still normal). It does have P0521 but if it was using B42 to determine P06DA, I would theorize that this code should have already set.

Conclusion 1: There are 4 oil pressure related codes and OP's vehicle set none of them when he unplugged the solenoid.

Conclusion 2: try a spare solenoid and see what happens. I think it will be 100% satisfied. If it didn't set an oil pressure code already, it shouldn't set one with a dummy solenoid plugged in.

JettaRed

iTrader: (1)

So, I set a couple of the P052 codes to F to see what would come up. They showed as faults and when I picked one and selected Tests, this is what came up. Not really useful.

kevm14

Yup, I saw that.

JettaRed

iTrader: (1)

Running a Test on P052100, and answering Yes to the expected oil pressure readings at the specified RPMs, we get, "All is A-OK. Ignore and erase." (Or something like that.)

JettaRed

iTrader: (1)

Makes me wonder if the whole thing is bogus. Kinda like the developers started off wanting to use the pressure sensor and then decided it wasn't worth the trouble, so they just put in a nonsensical test to wrap up the code delivery to get paid. I mean, really, "Check oil pressure" and "...erase the error code". That doesn't even offer next steps if the pressure is out of range. (That's for P052400. P052100 does have a few more steps, but basically coming to the same recommendation: "Ignore and erase".) I would have thought something more technical would have been provided, such as replace sensor, replace oil pump, replace engine.

kevm14

I agree. They didn't run oil pressure sensors for the longest time. So when they attempted to add one, they clearly didn't know how to do it and just gave up.

CaliBenzDriver

Look at the fault setting criteria to understand what conditions are checked. Each fault is based on a different set of criteria.

Reading the translated definition is often times vague. The criteria give you straight ECU truth

S-Prihadi

.
This value of or greater than 2.5BAR ( 36.25PSI ) at 2,500 - 3,500 RPM is not as low as M276.820 with oil solenoid control in operation. ( not defeated )
This is very interesting.
.



BASED ON CAR IN NEUTRAL GEAR, STATIONARY .
M276.820 3.0Turbo, at warm oil temperature when at 2,500 RPM is still within the regulated zone by the oil solenoid and will be at 27.xPSI or 1.86 BAR.
By 3,000 RPM, which is still within the regulated zone by the oil solenoid and will be at 27.xPSI too, or 1.86 BAR.
If one do slow throttling, up to 3,500 RPM , it is still within the regulated zone by the oil solenoid and will be at 27.xPSI or 1.86 BAR.
Only at 3,550RPM the oil solenoid is being de-activated by the ECM and oil pressure will shoot up to 55-60PSI or 3.8 - 4 BAR.



Duty cycle above 70% means oil solenoid is in ON mode, reducing oil pressure.




.



So, if that spec of M157 S63 oil pressure test as below is a true designed value :
value of or greater than 2.5BAR ( 36.25PSI ) at 2,500 - 3,500 RPM
There is a good chance that indeed this specific engine could have a slightly higher oil pressure setting, approx 10PSI compared to M276.820 3.0 Turbo.

The easiest is to get the Xentry as logger and do stationary warm engine , oil pressure test from idle to 4,000 RPM.
Do a screen video record.

We need someone with M278 and regular M157 and increased performance M157 from S63 to do similar warm oil pressure test as I did to have a good database.
If one's engine does not have Xentry accesible oil pressure data/sensor, one can use the Banks Gauge Data Monster type ,
also to show other OBD2 parameters from the engine....while having one of fastest logger ( non racing use ) in the market with its own display and massive expansion capability.
A bit under US$1,000 will get the Banks Data Monster and still have 3 extra analog channels one can add other* pressure sensors or temperature ( *buy separately)
.


HAPPY NEW YEAR GUYS

JettaRed

iTrader: (1)

NOTE: This is with the solenoid disconnected.

In my videos with a brand new external Oil Pressure gauge attached to my M276.825 engine, upon start, it takes about 6 seconds for the gauge to begin moving. I suspect that is because the gauge is new and/or there was air that needed compressing in the timing cover/oil filter housing (or at least I hope so). Then while at idle (~600 RPMs) the pressure rises to 20+ psi. As I raise the engine speed to 1500 RPMs the pressure rises to ~45 psi and stays there, maxing out at ~50 psi upon deceleration. Then the pressure seems to rest at 30 psi -- I should have continued recording. Maybe when I get a chance, I'll do this again. That said, the behavior was a little unexpected as I thought I would see 60 psi.

In the second (short) video, the engine is already running. The behavior appears to be the same, with max oil pressure ~45-47 psi. However, with the car in Park, I was not able to get the RPMs above 5000 (is this normal?). Even at 5000 RPMs, the oil pressure stayed at ~45-47 psi.

CaliBenzDriver

this is with "normal pressures", right?
Your engine sounds like the heads run pretty smooth now - That's a good sign for HPFP work, tensioner and VVT pin's life👏.
Twin dry HPFP kill the whole set down to the stretched chain. VVT compensates for late timings✌️

We see there is not a lot of difference at 1k.RPM between limited and normal pressure. That's what makes the engine VVT happy or perhaps what upsets VVT Phaser is to manage low pressures and get a shot of wildly different pressures on a simingly random basses.
This could be what drives the VVT ECU logic nuts!!!!

That would highlight the need for a VVT code development to rework the VVT control under switched pressures.

Currently the VVT magnetic adjusters are sayed to have fast response. How fast does the ECU senses the CPS saying the camshaft is going too far away and reduce the VVT PWM to adjust position from changing RPM and changing pressure???
ALL we clearly prove is... THAT'S NOT WORKING!!

- What we show is working is a linear rate of pressure increase linked to RPM increase.
- The difference with limited pressure is a different slope rate of increase.
> Switching between the two slope maps is the Bosch fix for performance loss (JAN 01 - SW FIX!).


Anyways, we personally can not recode broken firmware logic.
Instead we use what works rith now.

zk2004mb

No it does not. The cluster only shows temps. I also went through every corner of my scanner trying to find the live oil pressure, no luck.

zk2004mb

Another observation that might not be relevant:
The oil pressure sensor is not just a toy. Last year when I did the oil change, I messed up the oil filter cap not knowing it. The seal was not tight. When I started the car, the dash poped out a red message says engine oil pressure low.

Feels like I'm an idiot because it took me 3 hours to clean the engine bay thoroughly......

But it does tell me ECU is monitoring the oil pressure, at least by some threshold.

ImolaSix

This is some really good info. Too bad they did not install this across the board on all models/engines. Oil pressure sensor is such a vital component.

JettaRed

iTrader: (1)

That is VERY interesting. You're talking about the housing that the filter element fits into, right? Can you post a picture of the sensor and the cable attached? Does the operator's manual discuss that as one of the warnings in the IC?

What year is your car again?

EDIT: Never mind. 2015.

JettaRed

iTrader: (1)

No, it does not, unless there was a supplement or addendum added later. I got a pdf copy and searched the whole thing for every time oil was mentioned.