Oil Level Sensor - Inactive

[Ghostbear]

Hello folks,

yesterday my Coupe decided to warm up much quicker than usual. I wanted to look up the engine oil levels, the process took its normal time but then just quit.
Repeating the process now always delivers the "INACTIVE" Message instead of the level and miles to next Service have instantly gone down from 25000km to 3500km.

Today the car was almost 7km short on reaching 90°C. And instead of hovering at 100°C/110°C it hovers near 120°C. Which I only experience when going 120+mph for longer distances.

Has anybody seen this behaviour?
Is going into the garage on 10th of August early enough?

Oil has been switched to Castrol Edge Formula RS 0W-40 at 18.000km and I am now near 28000km Oil Levels haven't dropped since exchanging.
I am open to any suggestions

[Citizen Z]

Take it to your dealer, have them diagnose it.

[Ghostbear]

Dealer is booked until 10th of August

[The Cthulhu]

Get a Bavarian Technic tool for ~$300 and plug it into a laptop, post codes. I hate not having a dipstick...

[jeremyc74]

The oil temp sensor is integrated into the oil level sensor, which is in the bottom of the pan. The oil level sensor calculates the level buy monitoring how fast the oil temp changes (don't ask me to explain this, I'm just repeating what the documentation says), so it makes sense that if the sensor is screwed up, the oil temp isn't accurate. The obvious answer is to get the dealer to replace it, but it's interesting to me that the oil temp display is a symptom of a failing sensor. I'm really concerned about this system over the long haul, but at least there's an indication if it's not working properly.

[GtiGyver]

0W-40?

Is it REALLY cold where you live right now? 0W is a very bad choice of oil weight on a turbocharged engine, especially in hot weather.
Could lead to premature engine wear or worse.

[deamon32]

Originally Posted by Ghostbear

Dealer is booked until 10th of August

Thats some BS if you ask me.

[mad chemist]

Originally Posted by Ghostbear

Hello folks,

yesterday my Coupe decided to warm up much quicker than usual. I wanted to look up the engine oil levels, the process took its normal time but then just quit.
Repeating the process now always delivers the "INACTIVE" Message instead of the level and miles to next Service have instantly gone down from 25000km to 3500km.

Today the car was almost 7km short on reaching 90°C. And instead of hovering at 100°C/110°C it hovers near 120°C. Which I only experience when going 120+mph for longer distances.

Has anybody seen this behaviour?
Is going into the garage on 10th of August early enough?

Oil has been switched to Castrol Edge Formula RS 0W-40 at 18.000km and I am now near 28000km Oil Levels haven't dropped since exchanging.
I am open to any suggestions

Ghostbear,

Sounds like oil level sensor fault.

If you check with BT cable there will be an obvious code(s).

Mad.

[Ghostbear]

No BT scanner available sorry. I talked to the chief engineer, they do not think its critical. I know that this car does not lose much oil and it was full a week ago

I will update this thread after the car received treatment.

Edit: Damn Sensor started to work again on its own

[Ghostbear]

Update:
It seems that the water pump is working full time, and has to be exchanged. Will post further updates if more changes.

[jeremyc74]

Originally Posted by Ghostbear

Update:
It seems that the water pump is working full time, and has to be exchanged. Will post further updates if more changes.

Interesting!

The fact that the oil level sensor won't work properly when the water pump is running all the time might answer a question I had about how it actually works.

The oil level sensor is supposed to be able to tell how much oil is in the engine by how long it takes it to change temperature. I can understand how that would work when the car was below normal temps, but I was having a hard time figuring out how it could check it while you're driving down the interstate on a road trip.

This problem you're seeing would seem to suggest that they're altering the engine temperature using the water pump speed so the oil level sensor can take a reading. If the pump's running full speed all the time, the engine temp is probably just riding the termostat and there isn't enough of a change in the oil temp to get a level reading.

The more I know about this system the more it scares me, and the more I miss a simple dipstick.

[Ghostbear]

Okay here is what the service tech said, water pump was indeed running full time. Normally Oil Temp is a indicator for the engine when to engage the water pump, therefore messing up the temp readings and the oil level indicator.

New Pump everything works fine again, did have to drive around with a 90PS Clubman Mini for two days

Concerning the dipstick I was told that the techs miss it too, when sensory readings are messed up they normally drain oil and look for the filters etc.

[JB4Jonnie]

Im running into this problem right now and would just like to ask a few questions hopefully someone will be able to help with! I have an inactive oil level sensor right now but it wasn't like this before I brought this car to the dealer a few weeks ago due to what I have concluded was a bad alternator. The dealer said I needed new alternator and new DME lol. So after this I went to check my oil and it says inactive now what Im hearing here is that it could be the water pump running at all times which is what I believe shot the alternator only because in my JB4 I was running Maxcool and I think that was to much for the alternator to keep up with. My question now is do I have a bad pump or sensor???

[josephfarghal]

I have a 128i and ran into the same problem. I did what every video said to do and replaced the sensor and afterwards it still said inactive. This led me to think that it was the wiring harness and sure enough it was. Before you go out and spend a $100 on a sensor check your wiring. Now I have an extra sensor if anyone needs lol.

[Joseg0715]

Joseph farghal, what wiring did you check and replace?

[Bob128i]

Hello, enjoyed all questions and response. I just replaced my oil level sensor and still getting Inactive. Wiring was mentioned and does anyone have any input to what was done regarding the wiring/connector?
Thank you

[Pnalli]

Originally Posted by JB4Jonnie

Im running into this problem right now and would just like to ask a few questions hopefully someone will be able to help with! I have an inactive oil level sensor right now but it wasn't like this before I brought this car to the dealer a few weeks ago due to what I have concluded was a bad alternator. The dealer said I needed new alternator and new DME lol. So after this I went to check my oil and it says inactive now what Im hearing here is that it could be the water pump running at all times which is what I believe shot the alternator only because in my JB4 I was running Maxcool and I think that was to much for the alternator to keep up with. My question now is do I have a bad pump or sensor???

I know this post is ancient but for those reading it now.. My n55 135i had an alternator go out on the way to work a month ago. Seeing as bmw is a different breed in it's own one thing also means a thousand others. So I got a shop local to replace the alternator. Car cranks runs good for the most part,but oil level sensor reads "inactive" and bumps up to 1000rpm in and out at idol (in park/at stop). Had oil level sensor replaced. No fix. Turns out water pump is causing this issue according to tech. So I just ordered a water pump and will be replacing this weekend. If it doesn't fix the issue then I'll be back here with an update. A new alternator that was bad could've also been the culprit but my mechanic confirmed it was good. Good luck guys!