Update on my Self Level Suspension (SLS) issues

My issues started when the front right air strut deflated. Dealer replaced front right air strut. Cost £1000

A couple of months later we could hear a "flapping" noise from the front left on occasions when travelling over bumps. Car was checked by various mechanics and no one could find anything. Noise was very intermittent and when it happend, if you used the brakes whilst going over an uneven road surface the ABS kicked in way too early!

This went on for months with the symptoms developed very infrequently.

A few months later the dreaded SLS inact. warning came on the dash again.

Car was left into the Auth. BMW dealer who was asked simply to read the diagnostic memory and report as other than the message on the dash there were no obvious defects. Several days and £400 later the dealer said they couldn't find a fault. They had only been asked to read the memory!

Light stayed off for about 6 weeks then came back on. There was no way I was going to go back to the dealer at those costs so I dove with the light on whilst I made enquiries re an independant specialist who had the equipment to read and programme the EHC2 control unit.

A couple of months later I found someone who had previously worked for the Auth. BMW dealer. He reset the system but could find no obvious causes. The errors read from the module were CAN bus errors.

The light only stayed out for a couple of weeks. More CAN bus errors.

This went on for a while resetting and lights staying out for days or weeks. Errors were CAN bus errors and constant request for filling. But when the test cycles were run, everything tested OK.

Then one day the car was sitting low on the front left when I came back to it but as I unlocked the car it raised up to its normal height. Still no faults found.

Eventually the voltage reading on one of the ride height sensors was reading lower than the other three so wiring and sensor was replaced. This improved the voltage but otherwise made no difference. £120 sensor plus labour to fit rewire etc.

One day the back of the car was raised way up, much higher than the raised position. A rear ride height sensor was replaced and the car returned to normal height. Another £120 sensor + labour

The orginal SLS inact. message was still displayed on the dash.

The car then kept going down on the front left whilst parked. Usually overnight. Then it stopped going back up when the doors were unlocked but when the car was driven it went back to normal ride height. Still no component could be found at fault!

Eventually, months later, the front of the car dropped, both sides down to the bump stops!

Independant specialist could find no new fault, reactived the system and the car return to normal height. Just the usual CAN bus and constant request for filling errors registed in the control module but when tests were run, they were all passed.

I decided to change the front left air strut but when the old one was taken out there was no leak found! It was inflated whilst off the car and placed in a water bath. No leaks were found so the original air strut was placed back in the car.

It kept going down, now more frequently, on the front left corner. Now if it was down, it only went back to normal height when the car got over 50MPH!

Front left strut was replaced at nearly £600 but the SLS inact. message still remained.

The CAN bus errors disappeared but constant request for filling errors kept appearing. But now the car remained at normal height.

It seemed that the intermittent leak from the front left air strut may have gone on so long it knackered the air supply. There went another £600 to replace it.

Now not only was the SLS inact. showing on the dash but the tyre monitor light was now showing amber!

I was at this stage loosing the will to live. We were now 1 yr on since the deal charged £400 for the diagnostic and about 2 yrs since the first air strut had been replaced. But now we were getting a new error on the control module! Constant request for filling error had now been replaced by unexpected ride height.

The Control module which costs £670 has now been replaced and the car has now driven 250 miles with no messages on the dash.

We're hopeing that this is the end of it.

On an up side, the car hasn't handled like this since the very first air strut deflated!

It will be a very long time before I purchace another car with air suspension and although when it's working, the car handles a dream, it seems the system they have put in the 4.8is X5's is way too unreliable and too costly to maintain.

The reason I have put all of this on here is to hopefully guide some of you through your SLS issues. To put it bluntly, if your car goes down on a corner, first check the ride height sensor, if it's not that replace the air strut, even if you can't find a leak as if you don't it'll knacker your air supply too