Headlights are too low, I suspect level sensor issues

Palmetto Fellow

Palmetto Fellow

Member
 South Carolina
WARNING:
Wall of text and stream-of-consciousness below. Read at your own risk :LOL:

My 2016 Z4 headlight beams are very low. Like, maybe a car length or so from the front of the car.
I've determined that I likely have an issue with the level sensors. In doing research, I can't find anything on them in the Service Manual I've been able to download online. Searching keyword "headlight" did not produce anything meaningful on these sensors. Searching "ride level sensor" brought one hit for the bracket fastening torque of 8Nm, but nothing on the sensor itself.

So I then looked for videos or other resources like Youtube, and it's hard to find anyone who is going over the procedures for both front and rear. So I've decided that I'll need to figure a lot of this out on my own. I vaguely know what they look like and about where they are on the vehicle. Can I apply the same procedures as an E85? So far, all pics or videos I've found are closeups which do not give much context like how/where to position myself and reach the components.

RealOEM insinuated that it would be on the driver's side, but I couldn't find anything. I found the rear one on the passenger's side. I then realized that realOEM is likely giving examples from a RHD car, and not LHD :giggle:
I took off the rear wheel and was able to see the sensor (barely), but I determined that being under the car was the best approach angle for replacement.

37146853753 - Front Sensor
37146784697 - Rear Sensor

I didn't see anything immediately wrong with the rear sensor. I was able to manipulate it though. Almost like its position had changed, and I was able to get it back into place. Moving it to the other resting position didn't fix the issue like I had hoped. It's hard to descripbe how the sensor moved as I still don't exactly know what parts it's connected to and how it gets its input. I have yet to look at the front sensor but I assume it's also on the passenger side. This may be something for tonight.

1. How can I check the sensor voltage being produced by these sensors in real time? I've learned that it should be 0.5-4.5V
2. Can I code the car to ignore the sensor input for the purposes of aiming headlight? I found these two possible code adjustments. Will they possibly help me?
AUTO_LWR_ENABLE nicht_aktiv
DYNAM_LWR_ENABLE nicht-aktiv
3. Do any other systems use data from the level sensors?
4. What happens if I unplug them, will the headlights go to a neutral position?
5. On startup, when the lights move around, am I seeing the full range of motion? If I see them dip after the self-test, is that a clue?
6. Do I need to remove the wheels for sensor replacement & viewing angle or can i entirely find and replace from under the car?

I plan to eventually replace the sensors if they're the issue, but I am wondering how to best troubleshoot. If unplugging them will cause a neutral aim, then that would be sufficient proof that the issue is the sensor and not a need to aim the lights with adjustment screws. One goal is to avoid using the adjustment screws before ruling out any sensor issues.
 
Have you used a good code reader. It they are faulty it should indicate with fault codes. You should also be able to get live data from each sensor.

I would try this before you go any further as if it’s just a sensor you could mess all the physical settings up and enter a world of pain for a simple fix.
 
Reamesy said:
Have you used a good code reader. It they are faulty it should indicate with fault codes. You should also be able to get live data from each sensor.

I would try this before you go any further as if it’s just a sensor you could mess all the physical settings up and enter a world of pain for a simple fix.
Click to expand...
What's a good code reader? I've emailed BimmerLink, but they don't monitor these sensors, they specialize in engine sensors.
I have both the MHD Universal and VeePeak OBD2 interface modules at my disposal as well as Foxwell NT301, but I fear the Foxwell is mainly for check ingine lights.
Is there a phone app that will leverage the hardware I own to give me the sensor values I am looking for?
 
That’s what I do. No sim. Only use it for diagnostics. It’s worth the money.
 
Palmetto Fellow said:
What's a good code reader? I've emailed BimmerLink, but they don't monitor these sensors, they specialize in engine sensors.
I have both the MHD Universal and VeePeak OBD2 interface modules at my disposal as well as Foxwell NT301, but I fear the Foxwell is mainly for check ingine lights.
Is there a phone app that will leverage the hardware I own to give me the sensor values I am looking for?
Click to expand...
Bimmergeeks Protool is the gold standard app for taking an app as far it can go in coding /diagnostics/programmimg …next stop full bmw toolset
 
Let's say I get the Protool and read my voltages. What voltage on the front and rear sensors would you expect to see for the lights to be lowered to their max? I don't expect to see the sensors with faults. I expect the sensors to throw out valid values, just values that would tell the car to aim the headlights down. Will Protool allow me to see the level sensor values in real time?

Also with the Protool, I can try to use those codes I mentioned for telling the headlights to ignore the level sensors. Anyone have ideas on this efficacy? Would changing these codes be relatively minimal in negative impact?

AUTO_LWR_ENABLE nicht_aktiv
DYNAM_LWR_ENABLE nicht-aktiv
 
Palmetto Fellow said:
I didn't see anything immediately wrong with the rear sensor. I was able to manipulate it though. Almost like its position had changed, and I was able to get it back into place. Moving it to the other resting position didn't fix the issue like I had hoped. It's hard to descripbe how the sensor moved as I still don't exactly know what parts it's connected to and how it gets its input
Click to expand...
You shouldn’t be able to manipulate the sensor, the connecting rod should be fixed at both ends and the sensor should only move as the suspension height moves, from your description it sounds like the rod is disconnected or missing
 

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Palmetto Fellow said:
Let's say I get the Protool and read my voltages. What voltage on the front and rear sensors would you expect to see for the lights to be lowered to their max? I don't expect to see the sensors with faults. I expect the sensors to throw out valid values, just values that would tell the car to aim the headlights down. Will Protool allow me to see the level sensor values in real time?

Also with the Protool, I can try to use those codes I mentioned for telling the headlights to ignore the level sensors. Anyone have ideas on this efficacy? Would changing these codes be relatively minimal in negative impact?

AUTO_LWR_ENABLE nicht_aktiv
DYNAM_LWR_ENABLE nicht-aktiv
Click to expand...
That won’t fix the problem only mask it. Would you not be better fixing the root cause? Try Chippies suggestion. It could be a very easy fix.
 
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Reamesy said:
That won’t fix the problem only mask it. Would you not be better fixing the root cause? Try Chippies suggestion. It could be a very easy fix.
Click to expand...



Taking off the wheel and reaching in there blindly to play with the sensor is one thing. Determining the proper rod attachment will require Jack stands and some underbody investigation.

I’d also rather turn this feature off if it means instantly being able to drive at night. Technology is cool until it stops working.
Replacing both sensors with OEM parts is nearly $400 and more than a week.
Coding this feature off (if it returns the headlights to neutral) is almost instantaneous.

I’ll try to get the car lifted tonight after my walk and really put eyes on the rear sensor assembly. I couldn’t get my camera into the area to take decent pictures from the wheel well.
 
I had this on my 2016 e89 back in the day.

The sensors were not faulty per se and didn’t show a code, but the lights were pointing on the floor.
In my case, it was the rear level sensor bracket had bent possibly when I hit a bump and it went past its point. I don’t recall if they replaced the entire sensor or just the bracket. If you’re doing it yourself, just make sure you mount it the right way round.
 
Palmetto Fellow said:
Taking off the wheel and reaching in there blindly to play with the sensor is one thing. Determining the proper rod attachment will require Jack stands and some underbody investigation.

I’d also rather turn this feature off if it means instantly being able to drive at night. Technology is cool until it stops working.
Replacing both sensors with OEM parts is nearly $400 and more than a week.
Coding this feature off (if it returns the headlights to neutral) is almost instantaneous.

I’ll try to get the car lifted tonight after my walk and really put eyes on the rear sensor assembly. I couldn’t get my camera into the area to take decent pictures from the wheel well.
Click to expand...
It’s illegal in most jurisdictions to operate HID headlights without automatic self levelling and a headlight cleaning system….FWIW
 
My first guess would be that one of the sensors is out of position, I'd be looking at the front one on the lower(?) control arm. Can probably inspect it without the need for lifting the car if you're agile enough.
 
tiglon said:
My first guess would be that one of the sensors is out of position, I'd be looking at the front one on the lower(?) control arm. Can probably inspect it without the need for lifting the car if you're agile enough.
Click to expand...
The front ones seem to break off their mounts quite often..
 
All the advice is telling you to do visual checks for any obvious damage to one or both sensors. This would literally take around an hour max including wheel removal to get a good look.

It could just be a bent bracket.

I personally would listen to the advice and at least rule it out before making mechanical adjustments and coding.

Just a thought 🤔
 
Reamesy said:
All the advice is telling you to do visual checks for any obvious damage to one or both sensors. This would literally take around an hour max including wheel removal to get a good look.

It could just be a bent bracket.

I personally would listen to the advice and at least rule it out before making mechanical adjustments and coding.

Just a thought 🤔
Click to expand...
I fully agree that a mechanical inspection is the best option. It's ridiculously hot in my garage though and very hard to motivate myself to get under the car right now. I'd much rather save this repair for the fall.

Rather than jacking the car up and using jack stands (I do have all the hardware needed to do this), I am considering just using Rhino Ramps on the rear wheels. I believe my exploratory session had determined that accessing the sensor from the wheel well was not helping and that I need to get under the car. This will let me at least put eyes on the rear sensor which if you recall, I was able to move around to some degree. Chippie made it clear that this should NOT be the case. I am hoping it's just a bracket issue or connecting bar problem that I can fix without parts. This was one of my motivations to obtain the actual voltage output of the sensor. I hoped to manipulate the arm of the sensor and see the voltage change, indicating to me that the sensor itself was properly functioning. I did buy ProTools, but wasn't able to find a way to monitor the ride level sensor voltage in the time I tinkered with it. If anyone can point me to the part in the menu where I can find this, it would be great.

Based on what Chippie said, I know I have a problem with the rear. The sensor shouldn't have moved, but mine was able to move. A clear picture of the orientation of this area would be great. I haven't been able to find anyone who's shared their experience with pics or a video, so I am going to have to use my best mechanical judgement. One concerning thing to me is that I often see people warning about isntalling the sensor upside down. I can't wrap my head around how it can be put in the wrong way. For me, it either fits, or doesn't. The fact that it can fit multiple ways gives me pause. How can I tell if it's on correctly without a diagram of what "correctly" looks like. Without pics of a proper system, I am just guessing, and another excuse to delay the endeavor of getting under the car and getting it done.

We have rain coming in, so maybe the temps will not be 100 degrees this afternoon. If my garage is any cooler, I'm going to back onto my ramps and try to put my eyes onto the sensor and find out why it is able to move. I do see that this weekend will be nearly 20 degrees cooler than it was yesterday.
 
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