Disconnecting Oil Pump Solenoid gives me CEL
 

First I'd like to extend my appreciation to members who contribute to this thread https://mbworld.org/forums/w212-amg/...solenoids.html
kevm14 pointed out that the engine oil pump could potentially cause catastrophic results if it stuck at the "low pressure" position at high RPM.

S-prihadi and CaliBenzDriver did a very rigorous study on the M276 platform https://mbworld.org/forums/e-class-w...en-passed.html

And the take away is disconnecting the engine oil solenoid is beneficial in many aspects. Members in w212 platform who disconnected the solenoid reported positive feedback without a CEL. Everyone has fault code P06DA00 but none of the w212 throw CEL.

However, for my 2015 S63 Coupe (C217 chassis, M157 engine, pre-face lift), disconnecting the solenoid triggers CEL. Since it's a different chassis, that leads to two questions:

1. Why is there a CEL? (while w212 won't show CEL on P06DA00)
2. Will disconnecting the solenoid do any harm to the engine?

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.
However, the P06DA00 Code does throw the CEL in my dash. Which is extremely annoying.
It's the only fault code that relates to the engine from obd scan.
If I cleared the codes and turn on the engine, the CEL won't show up. But once I restart the engine, the CEL will pop back on.
The scanner I used is Foxwell NT510 Elite. Bought it from Amazon for like $180

One thing I could try is buying another solenoid and connecting it to the original cable. It might trick the ECU but it can't answer my second question.

Hope this thread can bring the oil pump solenoid issue to more members as almost all MB engines from 2009 to 2023 use this solenoid (Part #: A2781800415)

Many thanks!

charting the unknown ...
 

Okay, we are going to address the specifics of your chassis that flags an active CEL when the oil pump solenoid is disconnected to produce only normal pressure.

This thread is an addition to W212-AMG without CEL issue.
​​​​​​
> Default means Pressure
-- My first concern with a different engine was to validate disconnecting the pump control would default the dual-rate pump to normal pressure.

-- Your road test pretty well identified that right away. Inactive shut solenoid equals normal pressure: Great!

> Optional Oil Gauge:
You have pretty much proven normal pressure tracks up with RPM from 15Psi to 60Psi.
Different oil grade, temperature, age directly affect viscosity thus pressure.

-- The pump output is absolutely not regulated. It's not a bad idea to glance at what your engine is working with.
The VVT Phasers are tasked with setting camshafts timing regardless of oil pressure variations.


> Canceling CEL:
Let's fool the ECU to not detect a open solenoid circuit.
Here comes a dummy-load, be it a spare solenoid, a spare 12VDC Relay coil or a small side-marker bulb #194.

-- Use a pigtail harness extension (same as VVT Electro-magnets coil) + dymmy-load plugged into the car harness.

-- Zip-tie harness, connector and load to your liking so nothings flies into nearby moving serpentine belt. Use generous amount of RTV on connectors, they are hardly waterproof.


> Reported effects about...:

1. Firm throttle pedal response
2. TCU shifting relearn after >1k to 1.5kMi
3. Break pedal improved sensitivity
4. Engine strong linear response from 800.RPM.
5. Gradual engine improvement over 1000Mi
6. Homogenous heat spread through piston oiling
7. Radical idle sound transformation 1kMi.
8. Smooth quiet heads and HPFP operation.

I'd recommend to stay below 4k.RPM to let your engine relearn new improved timing maps.
No point in beating your over heated tranny clutches while they are still shifting late. Patience, tranny is the last thing to fall into place once the engine setles down.

:zoom:

The S63 appears to be the only model with a factory oil pressure sender. All other engines have a plug where the sender attaches on the oil filter housing. Therefore, other models do not monitor the oil pressure. They do not even have a wiring harness connection to where the sender is located.

Do you mind posting your VIN. I'd like to put it into XENTRY in simulation mode to see where the oil pressure is monitored by the ECU. That will at least identify where the oil pressure is observed and what the values should be. It might also help us understand how the ECU uses the information.

And here is what I wrote as my prognosis for you regarding the ability to stay unplugged but get rid of the CEL:

Furthermore, I'd be contacting the BenzNinja to see if he can work any magic in Xentry Dev mode wrt this code.

You may also get away with using a simple bypass resistor.

I'm actually on the fence now. On the one hand, I did feel the snappier low RPM response, on the other hand, I have 0 information on the actual oil pressure and corresponding consequences and I'm not a fan of uncertainty.
My thinking process is:
1. I need to hook up a pressure gauge to make sure disconnecting means high pressure all the time

2. If disconnecting = low pressure then we're done here. If disconnecting = high pressure we go to the next step

3. I need to figure out high pressure does not do harm to the engine. Will it stress out oil pump? Not likely. Will it lead to worse leaking? I don't know. What's the effect on VVT and other components? I need to study as I don't know much about them.
4. Once I have an understanding of all those topics, I need to sample data points, check possible leakings and other stuff. It will be an extensive amount of real-world testing. Sounds like a Mercedes Engineer's job:rolf:

5. 3 and 4 is based on the assumption that ECU does not monitor the actual oil pressure, it simply just sends out a command to the solenoid by preset RPM map. Given the S63 M157 has pressure sensor, what if the ECU relies on the feedback of the actual oil pressure and adjusts the solenoid accordingly? Will disconnecting affect the stability of the drivetrain?

6. If we're lucky enough to get over all the obstacles, then we can focus on how to disable the CEL. I could certainly try to piggytail a solenoid or find a technician to write codes. But I don't feel comfortable to just disable the CEL and call it a day. Too many uncertainties.:)

Like you said we're going into unknown territory, maybe I should wait for more empirical data points?

WDDXJ7JB6FA010304 have fun:rolleyes:

Yeah, I'm sure coding can get rid of the CEL. It's the difference between S63 M157 and E63 M157 that concerns me.

1. You will not have high (max normal) pressure all the time. Pressure will be dependent on engine speed, so you will have a linear increase in pressure until the max at ~ 4 bar, which is where it is limited.
2-4. Please read the XENTRY TIPS topic document.
5. Non-S63 engines do not have an oil pressure sender. As I stated above, post your VIN so we can look at what the pressure sensor does when simulating XENTRY, or get your own XENTRY and do your research.
6. CELs are primarily limited to emissions related faults, not warnings that a non-emissions part is about to break. There are other warnings for such things as brakes, airbags, autonomous braking, traction control, Distronic radar, etc. If you have lean codes or rich codes, you will get a CEL. If you have a malfunctioning A/C, you will get a CEL (because it is somehow related to emissions). If your secondary air pump is faulty, you will get a CEL. If your brake pads need to be changed, you WILL NOT get a CEL.

I posted the vin above. Eager to see what Xentry can tell us.

Working on it.

Well, that was a bust. Unless the oil pressure is used somewhere besides the ECU (control module N3/10), there are no entries for its use.

Does the Foxwell scanner tell you which ECU version you have?

MED177_M278LA_VC15

That's the one I used.

The ONLY possible connection I saw was MAYBE the intake and exhaust cams adjustments, though there was no specific reference or value I could enter for oil pressure. There was no oil pressure parameter presented in XENTRY.

The oil pressure data/tables for factory equipped oil pressure sensor M157 might only be accessible via WinOLS. Still don't understand why MB included it for this specific application. Maybe due to this being the highest state of tune (torque) for the M157?

I assume someone has already used this VIN to scour WIS for new info? If not I will later.

I don't think there's anything different about the valve operation on the S63. Other than the CEL.

I used it in XENTRY Simulation, but not WIS.

Update of today:
Jack up the car and plug back the solenoid with sacrificial harness. CEL gone. Now we can confirm unplugging is the reason behind CEL.

Did the CEL just turn off or did you have to clear the code?

need to clear code.
The first ignition after reconnect still shows CEL.
Clear the codes, restart several times, none of them showed CEL.

Dig some digging in Xentry. Haven't looked in WIS but that's next. Found that B42 is the oil pressure sensor and here is how it is wired. Also found the screen to display the value. B42 is not present in my E63 using simulation mode (as expected). Anyway, the check for the S63 is engine off, ensure displayed oil pressure is below 1.5 bar. Not a very sophisticated check. I guess I could have simulated a good and bad condition to see what it tells me...

https://cimg1.ibsrv.net/gimg/www.mbw...808899bece.png
https://cimg2.ibsrv.net/gimg/www.mbw...6cc44ac32b.png
https://cimg3.ibsrv.net/gimg/www.mbw...60a632e232.png

https://cimg4.ibsrv.net/gimg/www.mbw...a148cd217e.png

I couldn't find anything different as far as the code for why it throws a CEL on the S63 and not others.

Excellent work!

Did a short drive today to drop a package. Temp 50f outside. Engine was cold as it's only 2 miles.

With the solenoid plugged back on, I can feel the hesitation at low rpm. Gas peddle feels mushy, definitely some lag there around 1200rpm.
:nix:

That sux for you, man. Maybe some black electrical tape over the CEL symbol and unplug.

@kevm14 , did you find XENTRY takes a really long time to run with that VIN? Did you change any of the settings, such as location? I changed the tranny to 7-speed and the location to USA. Did you change any other values for the modules? B42 doesn't pop up.

Quick fix...
 

I am glad you took the chance to experience normality. Now you're experiencing withdrawals by comparison :nix:

We'll help you build a perfect dummy load harness to get full time joy again.


> BOM need :
1x pigtail donor harness
1x cheapo spare relay coil (AMZ, eBay, AutoZ...)
3x zipties to keep things tied down


> Prime goodness:
You can get this or similar at your door step tomorrow for less than $10
:y

https://cimg1.ibsrv.net/gimg/www.mbw...4eca1b92b5.jpg
SEARCH QUERY: "12VDC RELAY"

I tried to link this item but no-go :rolleyes: