[DJMATTB2005]

Hello all,

I purchased my 328i 2010 n51 back in November of 2023, upon purchase everything was great besides oil leak but I was able to read oil level until about a week after purchase (OFHG and Valve Cover). With the oil icon reading "inactive" I went ahead and replaced the sensor itself since I had the funds and assumed it would fix the issue, it did not, but the car did show "add 1Q" one singular time and never after. I voltage tested the wires leading to the connector and they were all receiving voltage. The next course of action recommended to me was to replace a ground strap, so I went ahead and replaced the ground strap from the frame to driver side engine mount arm. This ended up frying my FRM module, so that is now a issue, there is a local shop that I plan on taking a new module too once I purchase one (any reliable sellers??). My problem is still not being able to read the oil level (assuming it is not FRM related), I did an oil change and filter in late January 2024 at 7Q and added about 0.1Q of oil recently. Any advice would be great, so far the only next steps that I myself came up with are to get the battery and alternator tested at Autozone, and to repair my FRM issue. I have very limited garage space and funds as I am an average college student. I do have access to Carly, and INPA but my INPA always has issues opening up specific modules showing the "DATA TRANSMISSION" errors, hence why I have been using Carly Universal Scanner. Thank you for any comments.

Edit: Carly live data has been showing a 60V battery draw and codes I have after replacing the ground strap are 2E7C (BSD data bus Communications fault), A3B4 and A3C1 (FRM)
previously before the ground strap (I cleared codes) I had codes 2E84 (Electric Coolant Pump Missing), CDAB, 2E8B (IBS missing), 2ECC (alternator missing)
These are obviously from some sort of electric issues I am just not sure what or where.

[Hoody007]

Could be the other two modules on the BSD bus: the water pump, oil level sensor, and alternator. Frayed wires/ cheap components could be your issues here.

Regarding INPA problems: check the latency for your COM port. Make sure it’s set to 1.

Hope that helps!

[DJMATTB2005]

Originally Posted by Hoody007

Could be the other two modules on the BSD bus: the water pump, oil level sensor, and alternator. Frayed wires/ cheap components could be your issues here.

Regarding INPA problems: check the latency for your COM port. Make sure it’s set to 1.

Hope that helps!

I have only bought genuine parts, a lot of the wires look to covered in oily soot but not frayed or damaged, I also have set the com port to 1, with the same issues persisting.
Thank you for your help

[Bims328i]

That is honestly strange to hear replacing the sensor did nothing. I've watched a lot of stuff regrading replacing it while doing the OPG so I would think it has something to do with another module not behaving correctly perhaps.

I would be surprised if it is something like the battery or alternator as it is just the sensor and if you have a new sensor and it is still not working then it might be what then interfaces with the sensor that is having issues. Hope you get it sorted out!

[Hoody007]

Originally Posted by DJMATTB2005

I have only bought genuine parts, a lot of the wires look to covered in oily soot but not frayed or damaged, I also have set the com port to 1, with the same issues persisting.
Thank you for your help

What is the part number of your oil level sensor? I had the dealer replace mine with a part which supposedly superseded the old one - and it caused the same issues. If you have your old part it's worth cross-referencing those two p/ns.

[DJMATTB2005]

Originally Posted by Hoody007

What is the part number of your oil level sensor? I had the dealer replace mine with a part which supposedly superseded the old one - and it caused the same issues. If you have your old part it's worth cross-referencing those two p/ns.

I conveniently threw the old sensor out just this weekend after a month of holding onto it I'm surprised that didn't cross my mind. If I do recall correctly, the P/N's were slightly different. I won't be able to check the new sensors P/N until tomorrow when I get it on a jack.

[mictang]

Hoody007 is right, Bad water pump or connection can cause inactive oil level reading.

My water pump once shorted the BSD bus and fried a brand new oil level sensor (luckily it was not a BMW one).

More recently, I even had a water pump code (a few years after the above issue) due to a very loose water pump connector, bought a new plastic plug, de-pinned the old, put it back together, and problem solved.

Water pump electrical is easy to test, there are only 3 or 4 pins and there is a specified voltage to ground, worth checking out.

[DJMATTB2005]

Originally Posted by mictang

Hoody007 is right, Bad water pump or connection can cause inactive oil level reading.

My water pump once shorted the BSD bus and fried a brand new oil level sensor (luckily it was not a BMW one).

More recently, I even had a water pump code (a few years after the above issue) due to a very loose water pump connector, bought a new plastic plug, de-pinned the old, put it back together, and problem solved.

Water pump electrical is easy to test, there are only 3 or 4 pins and there is a specified voltage to ground, worth checking out.

I have read about this in other forums, but it is not something I am confident in doing myself without a more specific DIY process. If there is another forum you think does a good job at explaining a link would be appreciated.
Thank you for your help!

[DJMATTB2005]

Here is a picture of the writing on the new oil level sensor, as well as the attached link I purchased the new sensor from.

https://www.fcpeuro.com/products/bmw...er-12617607910

[sabino56]

Originally Posted by DJMATTB2005

Hello all,

The next course of action recommended to me was to replace a ground strap, so I went ahead and replaced the ground strap from the frame to driver side engine mount arm. This ended up frying my FRM module.

I’m curious how you fried the FRM by replacing a ground strap? Did you disconnect the battery to replace the ground strap?

[Hoody007]

Originally Posted by DJMATTB2005

Here is a picture of the writing on the new oil level sensor, as well as the attached link I purchased the new sensor from.

https://www.fcpeuro.com/products/bmw...er-12617607910

Interesting- that’s the part number of the sensor that ended up working for me (my N55 is a very late production E90, both part numbers were listed but the later p/n ending in 780 didn’t work for me).

Have you verified the IBS is present and plugged in?
You’ll need to go through the BSD system 1 by 1 to see which one is taking down communication. That’s the alternator, water pump, oil level sensor, and IBS.

Someone else had issues here and it turned out the PO had cut some of the lines going to the BSD system from the DME - I’d also check wiring for continuity as a last resort.

[DJMATTB2005]

Originally Posted by sabino56

I’m curious how you fried the FRM by replacing a ground strap? Did you disconnect the battery to replace the ground strap?

Yeah precisely, disconnected negative terminal before touching the ground, then re-attached the terminal after the new ground strap was on, started up and the FRM was not happy.

[DJMATTB2005]

Originally Posted by Hoody007

Interesting- that’s the part number of the sensor that ended up working for me (my N55 is a very late production E90, both part numbers were listed but the later p/n ending in 780 didn’t work for me).

Have you verified the IBS is present and plugged in?
You’ll need to go through the BSD system 1 by 1 to see which one is taking down communication. That’s the alternator, water pump, oil level sensor, and IBS.

Someone else had issues here and it turned out the PO had cut some of the lines going to the BSD system from the DME - I’d also check wiring for continuity as a last resort.

The IBS is plugged in, but reads missing (code:2E8B), will try to unplug all of them 1 by 1 soon and update the thread. Thank you again.