Thanks fellas. So my thinking Clavurian is that inpa probably looks at the 5v sensor output from the point where it's being regulated, wherever that may be, and not specifically at the sensor outputs for ehc. Most vehicles I have had experience of, have a 5v rail generated from a central point and that same rail is used for all the sensors and I am expecting this to be the case here. I will come back later with my findings.

So the old line, "buy cheap buy twice" has never been so true in this case, except you could replace twice with thrice here!

I end to end checked my connections today, from the EHC to the senser, all good. I then monitored the 5v rail leaving the EHC and regardless of ignition status the 5v was present.

The output of the sensor was then checked at the EHC unit end and the output was present only if the engine was running. the 5v rail to the sensor was then disconnected and with the engine running, the output was still there. The penny dropped..

Both times the problem appeared to clear the lights had been involved, first when I collected my daughter at night time, and when I filled up at the filling station where under the canopy it was dark and the lights had kicked in. with the 5v rail from the ehc disconnected the lights were switched on manually and there it was, output from the sensor.

5v to the other half (light position) to the sensor is present when the lights are on and when the engine is running. I am guessing the sensor has a fault and that the ehc side is getting its 5v only when the 5v is there at the lighting side.

So 2 dodgy sensors it looks like. I could link the constant 5v from the ehc over to the lighting side of the sensor I guess and in theory that should work, so long as the headlight system doesnt complain about seeing an output from the sensor when it shouldnt. Or I could just go to bmw and buy an OE part.

https://drive.google.com/file/d/1P-v...ew?usp=sharing

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

If you lose power to one side when voltage applied to the other it suggests a grounding or wiring problem (which can be internal of the sensor). Open ground that somehow grounded though the disabled hot (though it's usually rare to ground a hot when off, not that uncommon when you want to eliminate noise on disabled lines).

Is the 5v to wiring grounded when off? Test for good ground on any leads and end to end continuity before replacing the part.

Else cut the hot to the level side and power from the left as described above. Waterproof phone tap connectors are great for this type of connection.

Thanks Andrew,

I wasn't clear earlier, apologies. It's not about losing power on one side, its more that irrespective of whether the 5v from the ehc is applied to the height side of the sensor or not, there is no output from this side of the hall sensor. The only time you see output from the height side of the sensor is when 5v is applied to the lighting side of the sensor. To put this to the test, my original oe sensor had 3.4v or so coming out regardless of arm position, I today connected that back but only on the ehc side, and bingo 3.4v coming out of that with the -ve and +5v from the ehc module, working as it should in terms of not needing the lighting side of the sensor to be powered up. Yes, I use gel filled phone connectors often for this sort of thing, they lend themselves perfectly. Mini Wago connectors are great too.

Ah so you tested the sensor directly. If you are getting power from the wiring to the height as supposed to can't you cross power from there to the lighting side so there lighting side is always powered?

Also: warranty on the part? It does sound like part is defective. New ≠ fixed. Even more than once you can get a doa part.

Sounds like the cheap sensor is not dual. Only one single sensor internally connected to both pin pairs. Just out of interest you could test this with a multimeter.

I was thinking this, but not sure how the lighting side will feel about seeing an output on its side of the sensor when it wouldn't normally.

Yes, I may pull it out again and take a look. Car is back together now though, my other car (Supra) is currently on a SORN and dont want to tax it until the 1st of October and need to use the X5 for the next couple of days, will just leave lights on:dunno:

So just to conclude this episode, I ordered another sensor which this time had the same part number as the original, 1 093 700 instead of the newer type 1 093 697, sadly this gave exact same symptoms. Sensor output lost when engine not running or lights off. Leaving the lights on when starting and stopping is fine, but not practical in everyday use, as the EHC system monitors the height regardless 24/7. so even if you have the lights on when you finish your journey and get out without the error message being displayed, as you walk away from the car and the EHC doesn't see an output from pin 6 from the rear rh sensor, the compressor kicks in and jack the car up to full height and logs a fault. You could change the wiring so the ehc used pins 1,4,5 of the sensor instead, but seems a bit pointless when I dont know what effect that will have on the LWR module seeing a constant output, I am sure the 5v feed to pin 5 of the (LWR)sensor was switched for a reason.

I dug out the oem sensor, pulled it apart and verified that there was absolutely no electrical connection between the 2 halves of the sensor (pins 1,4,5 & Pins 2,3,6), by contrast the Chinese sensors have internal connections between these 2 sensor circuits.

Here's a video which shows that. Reluctant to spend any more money on this and to buy a new oem sensor from BMW until I knew for sure (lets be realistic here, the price of the oem sensor is about the same as a spring conversion kit!), I managed to get the old sensor freed off and put back together. Stuck it on this morning and everything is working as it should. Made this post and videos to help others in the same boat, I am sure there has been many people who have replaced the sensor, not fixed the problem and then ended up moving the car on or converting it to springs. I know of a 04 Range Rover near me that had endless issues, and the guy gave up and sold it in the end. I am now sure this was his issue.

To sum up. You may get away using the much cheaper chinese sensors on the other corners, but go for a oem on the rear right, or be prepared to at least change the wiring.


https://drive.google.com/file/d/1U5y...ew?usp=sharing

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

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

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

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

That's some amazing feedback. Do you remember the brand of the knock off? I happened to replace wife's right rear with AIP brand but coincidentally she didn't have air suspension.