That's interesting that with two axle air it uses doppelt front and back.

I wonder why they have dual sensors but maybe it works better to have a non linear resistor or reverse ramp for one system versus the other.

I have seen the voltage of the height sensor for air spring but never have seen the output of the headlight sensor option on my scanner.

[QUOTE=Clavurion;1210001]Like said xenon leveling uses right side front and rear sensors.

If the vehicle has EHC2 + xenons there is a sensor on every corner and both right side sensors have two circuits ("doppelt" = double).


Thanks for this info, I didn't realise this was the case, and also explains the 6 wires to the plug on the Rh rear. On mine, EHC1 + Xenons, replacing the front right sensor last winter instantly resolved the headlight issue. Thanks for the picture, almost identical to my original, although the number on mine ended 700.

The sensors are wired directly to EHC and LWR module which are located on opposite ends of the vehicle so it's reasonable that both systems have individual sensor circuits.

These sensors are hall sensors not potentiometers.

With BMW diagnostics (INPA, DIS or ISTA) you can see the headlight sensor voltage the same as EHC.

So just a brief update. Yesterday after filling up with diesel (yes it's true, don't believe everything you see in the media) I noticed the error cleared on the dash and started working. Stayed ok until today when it was a bit hit and miss. So I convinced myself it must be a connection issue and replaced the plug to the sensor. I left enough cable so I can take it all the way back to the ehc unit later on if need be. But sadly just the same. I was a fool really, while I had it apart I should have stuck the meter on the 5v feed to the hall sensor to see if that is as I suspect being dropped when the engine is turned off, pointing to a faulty ehc unit. Will delve deeper tomorrow but to me it's looking more likely now that the fault is indeed with that. Will stick some photos up in the next few minutes.

No access to those attachments.

Interesting, give me a moment and will check settings in drive

https://drive.google.com/file/d/1O4V...ew?usp=sharing

https://drive.google.com/file/d/1OFX...ew?usp=sharing

https://drive.google.com/file/d/1Nvd...ew?usp=sharing

https://drive.google.com/file/d/1O5s...ew?usp=sharing

Try this

So assuming the 5v to the right sensor is cut when the engine is stopped, as per the video yesterday, I am thinking next to use the 5v rail where it leaves the ehc from the left sensor to power the right side. Will let you know how it goes. Don't really want to buy a second hand ehc unit just yet until I have done everything I can to determine that's the likely issue.

Like you see on the lower right corner of the live status page the supply voltage to sensors looks OK the whole time. AFAIK the voltage to both sensors is produced by same components on EHC module so unlikely to be a module problem.

I am pretty confident your plan is a solid one. I would do the same thing. Also, if the right side is getting power for the headlight you may even have an easier fix; power from the headlight power.

Unless that is only powered when headlights are on, so back to power from the left side.