Check Engine Oil At Next Refueling
I changed my oil yesterday and within 2-3 minutes of driving (not sitting idle), I get the message Check Engine Oil At Next Refueling. I did this on my M276 3.0 liter biturbo. I drained about 6.7 liters and filled back in 6 quarts and figured I would top off once the oil was well circulated. I did check the oil level and added ½ quart to put the level toward the top of the measuring area. I have NEVER had this happen in the 3 years and nearly 30,000 miles I have owned the car. I did, however, use a new oil filer housing, so I may put the old one back on.
There's been discussion about this in the C63 forum, but the discussion was inconclusive. The odd thing about such a message is that there is no sense of a real emergency. If I had a full tank, next refueling could be a week or so.
There were no STORED or active (CURRENT) codes when I ran a scan. The message disappeared when cycling the car. So, my question is, should I be worried? What do we know about this message?
EDIT: To save folks from having to read multiple pages of comments, I am providing a summary.
The official reason for the message is that the oil level sensor switch has not been activated (i.e., the oil level is below the minimum measurement on the dipstick). The oil level switch is a simple single wire open/close switch activated by a float inside the oil pan. When the float raises to a certain point, it closes the circuit to ground. The ECU determines that there is sufficient oil in the engine. If the engine runs for a short while without closing the circuit, the ECU determines that the oil is low and displays that message. The problem is that you may have the correct amount of oil in the engine and still get the message. The next step is to assume the oil level switch is bad. I went and replaced the oil level sensor switch and still had the problem. I then checked the wiring to the switch by doing a ground continuity test on pin 13 of the connector X26 #4. Connector X26 #4 connects the wiring harness for the switch (and other components) to the ECU. I tested on both sides of the connector. By accident or coincidence, I discovered that testing pin 13 for continuity to ground on the ECU side actually reset some condition in the ECU that was causing the message. Since then, no more message. (There are pictures below showing the X26 #4 connector and its location.)
Last edited by JettaRed; Sep 8, 2024 at 05:45 PM.
I changed my oil yesterday and within 2-3 minutes of driving (not sitting idle), I get the message Check Engine Oil At Next Refueling. I did this on my M276 3.0 liter biturbo. I drained about 6.7 liters and filled back in 6 quarts and figured I would top off once the oil was well circulated. I did check the oil level and added ½ quart to put the level toward the top of the measuring area. I have NEVER had this happen in the 3 years and nearly 30,000 miles I have owned the car. I did, however, use a new oil filer housing, so I may put the old one back on.
There's been discussion about this in the C63 forum, but the discussion was inconclusive. The odd thing about such a message is that there is no sense of a real emergency. If I had a full tank, next refueling could be a week or so.
There were no store or active codes when I ran a scan. The message disappeared when cycling the car. So, my question is, should I be worried? What do we know about this message?
Strange that it happened after changing the oil and using a new oil filter cap/housing.
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I have only seen the oil level sensor on EPC parts diagrams.
Save your new oil jugs, you may reuse them to drain new oil out . This is an invitation to go remove the middle belly pan and add a magnetic drain plug while at it.
+++++ HEAVY RAIN...
I recall recently JR saying he was driving in a heavy summer storm... Here!
I know MB harness connectors seals are ineffective at stopping water (BlindSpots radar killer!).
Here I bet 80% chance the oil level connector got soaked. This read like an invitation for all of us to be proactive.
This is also what causes odd connection failures located down low :
- A/C compressor duty-control valve
- A/C pressure sensor at condenser
- Electrical Steering Rack (silicone!!)
- (rusted main GND strap)
- Exposed front bumper connector on right side
- Headlight connectors
- Winshshield washer tank
- .....
I also bet the oil level data is going to be heavily doctored by ECU to prevent false trigger for up-hill/down-hill variations. So may not be easy to correlate scanner datastream.

Last edited by CaliBenzDriver; Aug 24, 2024 at 02:54 PM.
As mentioned, I installed a new oil filter housing (the black upside-down cup thing that holds the filter element). Nothing was wrong with the old one but thought it might be prudent since the car is 10 years old. So this morning, I checked the oil and it was full to just a little above/touching the max level. But once starting the car, turning off, and letting it sit an hour or so, the oil was at the bottom of the dipstick. I removed the new housing, swapped the new filter over, and put the old one back on. My wife and I took a drive on both the highway and back roads, making several stops. We probably put about 100 miles on the car. NO MESSAGE. I'm beginning to think it was the new housing, but not sure why. Maybe the anti-drain valve was too stiff? Gonna keep an eye on it.
Last edited by JettaRed; Aug 24, 2024 at 06:18 PM.
As mentioned, I installed a new oil filter housing (the black upside-down cup thing that holds the filter element). Nothing was wrong with the old one but thought it might be prudent since the car is 10 years old. So this morning, I checked the oil and it was full to just a little above/touching the max level. But once starting the car, turning off, and letting it sit an hour or so, the oil was at the bottom of the dipstick. I removed the new housing, swapped the new filter over, and put the old one back on. My wife and I took a drive on both the highway and back roads, making several stops. We probably put about 100 miles on the car. NO MESSAGE. I'm beginning to think it was the new housing, but not sure why. Maybe the anti-drain valve was too stiff? Gonna keep an eye on it.








Check engine oil at next refuelling
Seems no urgency at all
Since this/our engine has no oil pressure sensor from MB, it must have meant oil level..... but not a LOW OIL LEVEL warning.
Our oil level sensor is a dummy one, it is either ON ( Low oil ) or OFF ( oil level OK ). It is not the true oil level & quality sensor like in M157 ( smartest ) or oldie M271.9 ( decently smart ).
Did you reset the oil change days/mileage counter after the oil change ?
What I think what may have happened is below :
You have your engine key ( assumed manual key in use ) in the slot, thus engine computer never really goes into deep sleep.
Or you use the PUSH TO START button, and your key in inside the car, also engine computer never really goes into deep sleep.
When you drained the old oil, ECM recorded Low Oil Level and when you refil with new oil, ECM detected normal oil level.
Above and not resetting the oil change days/mileage counter.....Maybe this is why that non urgent warning appeared : Check engine oil at next refuelling
I do not use PUSH TO START button, I hate that. I use manual key insert.
When I do oil change, I put my key FOB far away from the car, I want to make sure my ECM goes to deep sleep mode.
------------------
If you have not done resetting the oil change days/mileage counter, please do so and re-install the new engine oil filter housing.
See how it goes from there.
M276.8 Turbo is a 6.5s liter engine oil with new oil filter. 6.7 liters is OK, 7 liters is too much.
I'm not sure where the key was. I always use the start button in normal circumstances. But the car may have been ON (not running, of course) because I was checking the emissions readiness for an upcoming emissions test. But I have owned the car since December 2021, approximately 29,600 miles, and eight oil changes, and have never had this happen before. All my oil changes have been at 3000 and 5000 miles intervals. There is the possibility that I missed resetting the reminder a couple of times, but why isn't this a more common thing here? Searching the entire site, I would think this issue would have shown up often with most people following factory intervals of 10,000 miles.
Lastly, the warning message seems to have been reset by cycling the engine off and on. When doing a full car scan, there were no DTCs detected. When live streaming data to the ECU, the oil level showed NORMAL. But that was after the message was off. IF it happens again, I will try to scan for any codes before turning the car off. In the meantime, I have ordered a new oil level sensor (genuine Mercedes) from FCP in case this happens again. The message may be harmless, but it is disconcerting.




Do you remember when you last pluged-in your tune uploader dongle ?
Your CGW does: read freez-frames stamps.
> Random oil sensor fault...
Go inspect sensor connector for oxidation crusties or oilyness armed with silicone RTV for no-repeat protection.
At least the engine has a viable dipstick for eyewitness sanity!
> .... "Could Not Reproduce" : CGW GETS A FIX!
The Bosch CAN is resilient enough to keep running with detuned output when CGW is bugged out.
I still can't believe Bosch networking is proven to impact the performance of both engine + tranny error-free.
Simple chassis reboots FIX NOTHING but really help. I am going to share this reboot how-to pics.

Last edited by CaliBenzDriver; Aug 25, 2024 at 03:23 PM.
Apologies if I am stating the obvious.





95% chance these are STORED.
These are not transient faults.
This trully happened when DLC was used by dongle.
DLC open diagnostic port is not too robust to support additional payload.
Last edited by CaliBenzDriver; Aug 26, 2024 at 02:58 AM.
Do you remember when you last pluged-in your tune uploader dongle ?
Your CGW does: read freez-frames stamps.
> Random oil sensor fault...
Go inspect sensor connector for oxidation crusties or oilyness armed with silicone RTV for no-repeat protection.
At least the engine has a viable dipstick for eyewitness sanity!
> .... "Could Not Reproduce" : CGW GETS A FIX!
The Bosch CAN is resilient enough to keep running with detuned output when CGW is bugged out.
I still can't believe Bosch networking is proven to impact the performance of both engine + tranny error-free.
Simple chassis reboots FIX NOTHING but really help. I am going to share this reboot how-to pics.

@BenzNinja spent about an hour looking at my car yesterday and could not find any errors using both XENTRY and DTS Monaco (which apparently can dive much deeper than XENTRY alone). Since my oil level was good, he believes the message concerns oil quality, not quantity (i.e., 229.5 vs 229.3). But we checked and it seems the software always defaults to 229.3. The oil quality setting is used to determine the travel intervals (mileage) between oil changes. Everything was reset to zero.
My conclusion at this point is either it's a bad connection (as Cali suggested) or a failing oil level sensor. The car also just turned 50,000 miles and probably actually 10 years old. I have a new sensor on order. It's about $50 for a Mercedes Genuine part from FCP.





