Many of you know I have had issues with the car and my Variable Damper system. This has been going on for 11 months. I knew a week after buying the car that something was off, it just didn't feel like a BMW and had vibrations and instability in the rear especially.
The seller helped me with cost at BMW for 6 months but as they kept saying no issue he eventually stopped once I was outside his warranty (we didn't fall out over this) I bought ISTA and a cable and investigated myself while learning all about the cars system. I changed items that BMW told me to (totally waste as the alloys and tyres were not the issue as I suspected) or that I felt were the issue.
In summary don't let BMW try solving a VDC issue as they haven't a clue how it works and tend to just blame tiny buckles or tyres or tracking or anything else. They didn't even check the VDP module as standard. Other issue is no fault codes are kicked for malfunctioning VDP or ACSMs.
The ACSM is a very sneaky piece of kit, seems it is noted as only to do with the air bags etc, but it also had the huge job of controlling the entire flex ray system and all sensor feeds to every module in the car, hence if it malfunctions it can cause all sort of issues.
I'm convinced BMW messed up my VDP and ACSM when I had them do a full IStep software update a week after purchase.
Thank the gods for KUBAX on here he was the person who helped me change the VDP recode it and recode my ACSM today which finally has the car fixed.
Next steps are to get it remapped and ceramic coated as I wasn't willing to do either until I fixed the Variable Damper issue.
For anyone interested to date in sequence with cost in euros
Car unstable ride in town over uneven surface
• Refurbished alloys (500)
• Changed tyres non-RF (1170)
• New alloys and tyres with RF (3600) (old alloys were 759Is and had manufacturing defect BMW refused claim as I refurbished them but only because BMW had dented one of them go figure)
• RFB on alloys (100)
• Changed tyres to MPS4S (1200)
• Multiple trailing arms and rear subframe inspections incl. RSF bolts replaced by BMW (500)
Vibration on highway now added to unstable in town
• RFB on tyres (100)
• Changed VDC cable front left (50)
• Changed VDC shock front left with used one (350)
Noticed that VDP voltage was 6ma to front left and all other zero makes no sense
• Changed VDP module and had coded (300)
Most of instability gone vibration remains and all shocks get 2 ma but front left gets 3 ma.
• Changed back to original tyres (100)
• RFB on tyres (100)
Vibrations gone was related to the MPS4S tyres being defective but seems like one shock rear right feels harder than all others in town and front left gets 3ma still.
• Michelin refunded me to a credit note at BMW (1170)
• Changed rear ARB drop links (220)
• Changed rear left bearing (200)
Scoped all shocks while driving over bumps seems they are fluctuating wildly when going slow, video on you tube. Higher amps = harder shocks. 2ma seem to be rest state but changes in Ma don't correlate to the shock that hits a bump.
Decided to have ACSM recoded and VDP (100) FINALLY FIXED::
So spent Euro 8590 and received Michelin credit back to BMW at 1170 total = EURO 7420
If BMW had identified the issue, it would have cost me for new alloys and tyres and a new VDP plus ACSM and VDP coding = EURO 4100
Wasted Euro - 3320 because of BMWs inability to understand their own cars and refusal to properly diagnose even when told to do so and paid.
ACSM recode solved the issue thank the gods and Kubax!!!