EHC issues and 2nd intro
 

Hi, although this is going to show me as a new member posting for the first time, in fact I joined a few years ago, but its so long since I logged in, I have since left the job I was in and dont have access to that email address to retrieve my account. Had a few e53s now, all diesel and all manual.

So, on to my latest problem with my current X5 that has me a bit baffled. its a 2004 6sp manual diesel, M57 with Air on the rear, shocks on the front. I started getting the "Self levelling Susp inactive" message and by using INPA discovered that the RH rear sensor was not providing a meaningful output, INPA reported it was about 3.3v and didnt vary with conditions, Left hand side was fine. Fault code logged was something along the lines of no valid info within the prescribed time period. I replaced this sensor, probably foolishly, with a cheap ebay unit. This produced no output at all and I got the 0V error for the right side with an instant fault code generated, unlike the original sensor that took a short while after clearing to re-appear.

I bought a Febi sensor and this time it all looked great, could move the sensor arm and see the output vary on INPA, great I think, chucked it back together, cleared the codes, went for a drive with lap top hooked up and all looked great.....until I switched off the engine and bong, there it is, the 0v message back. Start the engine and I can see the output and working correct, clear the code, go for a drive and its fine right up until I back the key off when the code appears and the car starts to jack up to max, as it does when its inactive. Now, what's odd, when I back the key off, the left hand sensor still provides a meaningful output, however the new RH sensor drops to zero immediately the engine stops and the code is generated. I have pulled the EHC module and checked for dry joints, made sure the plug/socket looks ok. Do I have another rubbish sensor maybe. Anyone know what should be on what pin of the sensors? I have a scope and the ability to delve deeper if someone can point me to the sensor pin outs. Sorry for the long post, just trying to get as much info over as possible. Thanks in advance. Shane

Are the left and rear sensors the same? If so swap just like you would to root out a problem with abs sensor or an ignition coil.

I don't know where the sensors go but if you can determine if the problem is at the sensor or upstream is the first step.

It's very likely a worn wire or connector upstream off the sensor.

Swap the sensors if you can if the problem stays right it's upstream on the right side if the problem Swiss sides it's in the sensor.

New ≠ fixed. Follow the symptoms regardless how new the part.

Also: contact xo about possibly recovering your old account if you had a valuable history on xo.

Thanks Andrew, they are the same yes, and I have considered awapping them, a little weary purely because the bolts and brackets to the sensors are a little tired, as was the case of the faulty RH sensor and don't want to kill a tired but functioning sensor. It its certainly worth a bit more thought, oddly, I have juat been out to collect my daughter and its currently clear and staying clear, sort of pointing as you suggest to a connection issue. I know that the sensor end of the loom on the L322 range rovers that share the same platform as our e53s suffer from cable failure and a section of loom and plug us available as a repair kit. I guess as they are so similar in design, it's logical to assume it could well be the case with the x5s. Will report back, when I have something to update the thread with.

Intemittent and drop to zero hints at a broken wire that touches most of the time and opens at just the right conditions.

I had to refurbish the joints of both my rear level sensors and I recommend you do the same (or replace the arms that contain the joints). It's a defective design that will rust solid and will self destruct eventually.

The balls will pull out of the socket you can spin them in a drill to remove the rust and pack the joint with thick grease when you pop back together.

The bolts that hold the sensors are hardware common parts so don't be too concerned about breaking one.

If you have xenons with auto leveling the rear right sensor has 6 wires and separate circuits for both EHC and xenon leveling. The left side sensor has only one circuit so you can't swap them like that.

Nice catch that kind of sucks for testing


Sent from my iPhone using Tapatalk Pro

I suspect that may be the case for 2 air axle vehicles, but not on mine. I have Xenons yes, but there is a separate level sensor for those, RH front. How do I know? Because it failed last winter and needed replacing before I could get it through the MOT as the beam was way out for the test.

In the meantime, here's a short video that possibly explains the EHC problem better.
https://drive.google.com/file/d/1MJF...ew?usp=sharing

Edit: Just found this and it could bre just what I need: https://www.pngegg.com/en/png-hkiqr Will take another look tomorrow.

Xenon leveling looks at the front and back sensors both axles affect the headlight aim.

It's more common for faults on the front sensor (such as the arm getting flipped sideways vs. down) to cause the headlights to aim almost straight down but fault in the rear can cause similar problems.

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).

https://www.railwayautospares.com/pu...img_2863_1.jpg

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.

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.

Hi Andrew, one of them was branded "Dream", there's a certain irony about that! One was meant to be a Febi, but it was identical to the Dream, with no markings whatsoever, and not for a second do I believe it was a genuine Febi part. Not sure on what brand the one from Amazon was, will take a look and let you know. They will work, so long as pins 1, 4 and 5 are the only ones required, maybe that's why your one is ok. Pins 2, 3 and 6 are used for the ehc, so if yours had been done away with for springs then that could explain it.

Used it quite a bit today and so far so good. But...all that driving around with the suspension jacked up has killed something on the back and I have a nasty knocking that needs looking at. Sounds like drop links, but I have only just replaced these. So next job is to identify where my knock is coming from.