W211 Bluetec - Check Engine Code Question - PeachParts Mercedes-Benz Forum

WaarrEagle · #1 07-13-2021, 08:52 PM

What a great forum! I recently acquired my FIL's E320 Bluetech (OM642) with 230k miles and am trying to get it tuned up. This is my first diesel so I am drinking from a fire hose. An oil leak appears likely to be the oil filter housing gasket (oil cooler has been addressed), so that is on the to do list.

It also has a check engine light and my generic code reader is pulling:
P0544 - Exhaust Gas Temperature Sensor Circuit
P2000 - NOx Trap Efficiency Below Threshold

Is there any value in buying a MB specific code reader? Looking at the iCarsoft MB II. Or am I getting all the info I can get?

engatwork · #2 07-14-2021, 05:51 AM

If you plan on keeping the car get one.

Does it use oil?

WaarrEagle · #3 07-14-2021, 11:00 AM

I plan on keeping the car if the oil leaks and CEL are not big $$$ repairs. I am pretty capable at DIY and the oil leak appears manageable.

Any intel on those codes? The ~$150 for the iCarsoft is not a big deal but curious how much more info it will give me vs what i already have.

Unsure on oil use. It has leaked for so long and my FIL was always topping it off. He gave me an unopened gallon of Mobil1 0W-40 that is not MB diesel approved, so that concerned me. Hopefully his oil change place was using the right oil.

dieselbenz1 · #4 07-14-2021, 11:53 AM

I much prefer the foxwell scanner for Bout the same money. It has a lot of self test functions in addition to reading all their edges specific codes.

engatwork · #5 07-14-2021, 03:02 PM

Uh oh, that engine is supposed to use the ESP rated oil only. Reason I asked is I had one in shop that had received the wrong oil for 250k miles and it was using a qt every 300 miles.

jay_bob · #6 07-14-2021, 06:28 PM

I’m afraid he didn’t pay heed to the label right next to the oil fill. That little label that says use only the proper oils in this engine or it will cause emission damage.

The particulate filter is probably wrecked from the ash content in regular oil. It is the one under the vehicle about under the passenger’s seat. But before you condemn it double check that the differential pressure sensor across the filter is not clogged up. There are 2 tubes coming out of the filter that go to rubber hoses that go to a sensor underneath the car. Make sure the filter ports are clear, the hoses are clear, and the sensor ports are clear before shelling out $$$$ for the new DPF.

The oil filter housing can be resealed, there is a Dorman kit on Amazon
https://www.amazon.com/Dorman-926-365-Filter-Housing-Mercedes-Benz/dp/B08K1LXKWQ

You get both the middle of the neck gasket as well as the flange to head gasket.

OM642 oil filter gasket

EGT probe is in the base of the turbocharger. You may not be able to get it out without pulling the turbo

OM642 VNT Turbo actuator issues

And the mother of all threads on the oil cooler seal replacement on the 642 (step 1 is pull the turbo so you can swap the EGT probe while it’s out)

A journey into the the infamous Om642 oil cooler leak!

I have had tons of experience with mine, fire away with the questions and I will try to help. I fixed mine up and handed it down to my son and now he’s driving it. He has about 230 k on his too.

engatwork · #7 07-14-2021, 06:37 PM

The car that came in had been serviced by the dealer all that time using the wrong oil. Once I pointed it out to owner they approached dealer and came back with some kind of settlement that they did not disclose. Anyway, it had plugged the dpf and the dealer changed it and then it plugged again within just a few hundred miles. I suspect it had issues with the rings and never heard back. The dealer did start using the appropriated ESP oil during servicing in the bluetecs from there on though.

WaarrEagle · #8 07-23-2021, 11:43 AM

Appreciate all the input! I changed the oil filter housing gaskets this week and it greatly reduced the oil leak but unsure if it 100% stopped. I may have some other small sources, but it no longer drips when parked.

As to the codes, I reset the CEL with my basic code reader several hundred miles ago and it has not come back yet.

I bought a Foxwell NT510 elite and pulled the attached report from the car. This is my first time using a non-basic code reader. It looks like very few of these are "current", so i think they are old codes. So I should reset and see what comes back?

dieselbenz1 · #9 07-23-2021, 12:19 PM

The report looks not bad. Yes clear all codes and reread in a week. While you are connected maybe preform an engine check where the foxwell runs it up and checks the turbo charge and preforms the various other diagonistic checks.

jay_bob · #10 07-28-2021, 09:14 AM

Agreed this car will set codes if you fart in the drivers seat.

The SAM codes are most likely burnt out light bulbs in the past. Yes a burnt out headlight sets a code.

Mirror heater, that’s a common problem, the glass has a heater in it that dies. New glass about $100 or so and easily changed. By your handle I am guessing you are in the southeast so that’s something that may be handy if you park outside a lot.

Drill down into each category and make a note of what it finds. Clear all and see what comes back.

WaarrEagle · #11 07-28-2021, 08:48 PM

Lots of good progress to report! After some final cleanup, I believe the oil leak is 100% solved. No drips of any kind.

It currently has Mobil1 Turbo Diesel Truck oil so I have some ESP appropriate oil arriving this weekend.

On the codes, I reset everything and drove for several hundred miles. I checked the codes again and all were gone except for:

2940-002: Boost pressure control via throttle valve Negative control variation CLOSED MAJOR - Stored
3149-008: Characteristics of NOx storage catalytic converter Oxygen sensor upstream of NOx storage catalytic converter (negative signal edge)- Stored
930C: Knowledge base configuration incomplete.- Stored and Current

I did not check freeze frame data before, but freeze frame for the top 2 codes has the mileage and frequency. Both with a frequency of 1 and mileage is in the 71XXX km range. The car currently has 230k miles so that confuses me. I reset those codes again, verified they were gone, and plan to run it some more.

Any intel on why the freeze frame mileage is so off?

jay_bob · #12 07-29-2021, 10:30 PM

Boost pressure control is the turbo VNT actuator. See VNT thread I linked above.

The other one is your O2 sensor upstream of the cat (the vertical cylinder on the right side of the rear of the engine bay, in between the turbo outlet and the exhaust pipe under the car).

I have seen date/km weirdness in the freeze frame data like that too.

WaarrEagle · #13 08-01-2021, 01:48 PM

Thanks Jay for the info on the codes. I am going to watch them a bit more before replacing anything. See how many times they trigger and if the CEL comes on.

I also figured out the KM reading in freeze frame. It is the # of KM since the last even 100k km. So in my case: 231k miles = 372k km - 300k km = 72k km, which matches the freeze frame data.

My top priority at the moment is the significant oil leak that came back from the oil filter housing. It appeared to be coming from the top bolt of the charge air duct, the one that screws into the oil filter housing. (see #3 on the attached engine diagram, and the red circled hole on the housing) I recall when tightening it that it "stripped" and would not tighten further. I figured oh well, it would still hold and left it. The car was drip free for several hundred miles but that changed this week.

After a bit of research, it dawned on me that perhaps I installed the wrong (too long) bolt and punched through the bottom of the bolt hole into the pressure envelope of the oil filter housing. To test this, I removed the bolt and started the motor. Oil shot out everywhere!

So, I now need a new oil filter housing. Not a big deal. I'll compare bolt lengths when I get it off to make sure this doesn't happen again.

jay_bob · #14 08-03-2021, 09:39 PM

Yeah you got to be super careful with bolts on this engine, they like to mess around with mixed bolt lengths to trip you up. Also always use a torque wrench and the WIS spec torques for *anything* threading into this engine block or head as it is aluminum and you *will* strip out the threads in the engine if you over torque it.

Good to know on the freeze frame km calculation.

The filter housing is available from the dealer, you will get a new flange to head gasket and a new oil filter already installed!

WaarrEagle · #15 08-08-2021, 11:14 PM

Installed a new oil filter housing and the oil leak is 100% resolved, hopefully for good. I also changed the oil to something MB approved.

I then took a 500 mi road trip and the CEL is back. Cleared a couple times and it returns. I had a 0299 Turbo Underboost code the first time. It has not come back, but now I am getting the same 2 codes from earlier (3149 O2 sensor, 2940 Boost pressure control). Oddly, while pulling those codes, a 3rd started appearing after my initial data scan: 2592 - Check component Charge pressure positioner .Positioner signals fault Y.

I am reading through the turbo VNT thread and whoa, that does not sound fun. I guess this week's project will be to explore that linkage further and see what is going on.

I also noticed I still have the old style PCV. Could that be crudding up the turbo and causing these problems?