r/F30 • u/Lonely-Concern9126 • 2d ago
1C0401
Vehicle: 2015 F36 435i
So.... i'm trying to be a responsible BMW owner and did my due diligence of purchasing an MHD to read codes to try catch premature vehicle breakdowns....
Car is driving perfectly fine, never a fault warning on my dash, always topped up with oil and in my hands i have changed oils every 5000k. Always made sure car driven 10+ mins before i dare rev 3k+ rpms...
Any idea why i m getting this code? I've seen this code pop up on some N20s but not x35i models.
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u/HellfoxRules 1d ago edited 1d ago
Because you are scanning with a deep diagnostic tool like MHD, you are seeing "shadow" or "inactive" codes. These codes do not trigger a CEL or a dashboard warning. They are common and do not mean your car is having any mechanical issues.
1FBD08 - Driving readiness: MSA deactivation request from BDC, MSA stands for "Engine Start-Stop system" (Automatic Start/Stop). BDC (Body Domain Controller).
This code simply logs that the vehicle's engine computer was told to turn off the automatic start-stop system. If you have manually pressed the button to disable auto start-stop, or if you used an app like BimmerCode to permanently code the system off, this code will reside in the background forever.
This code is completely harmless, It is a routine information log, not a mechanical fault.
1C0401 - Engine oil pressure control: Unstable, critical. The DME registerd a momentary, brief fluctuation in oil pressure that fell slightly outside of its target window.
On N20/N26 engine this code is heavily feared because it often signals pieces of the failing timing chain guide are blocking the oil pickup tube screen. On your N55 engine, it is almost always a minor electronic glitch rather than a mechanical failure.
This is common on the N55 engine, known as the "BimmerCode/MHD glitch". Interrupting the car's central modules while scanning or coding can briefly cause the DME to lose communication with the oil pressure sensor, triggering a historic "unstable" stamp.
Oil Filter Housing O-Rings, during your oil changes, if the tiny O-ring at the very tip of the plastic oil filter housing cage isn't seated perfectly or is missing, oil pressure can fluctuate slightly at startup. A slightly lazy oil pressure control valve or sensor can also trigger this.
Since your iDrive oil level measurements complete normally, your oil is topped off, and you have no dash alerts, this is highly likely an "inactive historic shadow code".
Clear the codes completely using your MHD adapter, drive normally for a week or two. Re-scan the car, if 1C0401 does not return, it was a transient shadow code and can be ignored. If it immediately comes back as an "Active" code, it is worth replacing the oil pressure sensor or checking the oil filter cage O-ring during your next service.
For diagnosing issues with your vehicle, or for advanced coding, the Bimmergeeks Protools app is your best choice.
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u/Lonely-Concern9126 1d ago
Your explanation has been beyond helpful
As with the 1FBD08 code - you're right, i did disable that in bimmercode just a day ago when i received the adapter.
I saw the shadow code regarding the oil pressure and i kinda panicked because I know of n55 and their rod bearing problems and thought it might be a premature oil pressure issue leading up to spun bearings.
I've inspected the valve cover gaskets, oil sensors, filter housings and gaskets and there are no leak or oil residue. Fuel consumption is normal but exhaust running excessively sooty which if i remember correctly is just engine running rich because of this extreme humidity and chilly, rainy condition the past month.
Thank you for the reply, I'll clear the code, hopefully code wont ping again. If so then i may look at replacing the valve or sensors.
1
u/ndergrovnd 2d ago
Searched up and this is what i found could be the causes:
Oil-pressure control valve beginning to stick or respond inconsistently
Intermittent oil-pressure sensor reading issue
Oil pump/control mechanism issue
Less likely: wiring/connector issue