markben
Senior Member
- Joined
- Feb 12, 2017
- Messages
- 227
- Reaction score
- 305
- Location
- Bristol UK
- Your Mercedes
- w220 2004 S320L CDI
Greetings all
Has anyone here had problems with overly-hard damping in their S class? Despite 4 new Mercedes Reman OE air struts & valve block, numerous 'No Fault' SDS reports & many other more obvious causes eliminated, my Adaptive Damping is 'stuck' either in Sport 2 or Level 4 Hardest / Safety mode. The car rises ok on the dash switch, never 'drops/ sags' and the ride height is always even. BUT... the Adaptive Damping is as hard as a rock / effectively rigid in 'Comfort' mode even at sub-30 mph speeds in town over minor road undulations, ridges & ruts, speed humps etc. Ouch! .
Even my local specialist auto electrician is stumped after live-streaming voltage to the struts with an oscilloscope: they all appear to be actuating (so in theory the solenoid damping valves are fully Open for Soft Compression & Rebound Level 1 setting?): but in reality they aren't. Also: no signs of water ingress / dampness under the carpets where many of the electrics are routed.
Before you ask: the car is an immaculate, cherished 135k mile 2004 facelift S320L cdi running on standard 17" alloys with newish OE 225/55 94W rated Continental tyres at the correct pressures. It drives perfectly straight, has new OE front suspension arms etc, connectors to struts checked for corrosion, airmatic ECU swapped for a used / tested one, sensor readings all within range etc. - I could go on & on. Only to say that after 5 years the problem persists. Another clue: the new OE suspension arms have been replaced AGAIN after only 14k miles since last done due to being 'mashed' (my helpful local Mercedes Indie says they should last approx 40k miles in normal driving conditions, and I'm a gentle driver). Evidence enough that I'm not imagining the problem? (I know S Classes well as a former MB sales exec & latterly head office training consultant on many Ride & Drive events - 'Magic Carpet' Ride & all that?) .
John Daly (here - thanks) kindly suggested that a 'hidden' bad connection to / from a relay, SAM or other electrical component in the ADS system might be causing the ECU to shut-down the ADS into Hardest / Level 4 Safety mode - but without throwing a code on SDS or any warnings on the instrument cluster. When I first had the car there was a brief 'burning rubber' smell in the cabin: never to be repeated, but at the same time the cause has never been never found. Strange or what?!
All thoughts & suggestions welcomed from any W220 owners who've had similar 'mystery / hidden' (i.e. no SDS fault codes) electrical problems - or any Mercedes Techies who might be tuning in? Or.. would anyone in the South / South West with a 'healthy' (airmatic / ADS wise) W220 of any variant like to meet-up and drive my car / give me their opinion on the hard damping problem? (I'll be happy to travel to you & buy lunch in appreciation).
Thanks all
Mark B. (Bristol area)
Has anyone here had problems with overly-hard damping in their S class? Despite 4 new Mercedes Reman OE air struts & valve block, numerous 'No Fault' SDS reports & many other more obvious causes eliminated, my Adaptive Damping is 'stuck' either in Sport 2 or Level 4 Hardest / Safety mode. The car rises ok on the dash switch, never 'drops/ sags' and the ride height is always even. BUT... the Adaptive Damping is as hard as a rock / effectively rigid in 'Comfort' mode even at sub-30 mph speeds in town over minor road undulations, ridges & ruts, speed humps etc. Ouch! .
Even my local specialist auto electrician is stumped after live-streaming voltage to the struts with an oscilloscope: they all appear to be actuating (so in theory the solenoid damping valves are fully Open for Soft Compression & Rebound Level 1 setting?): but in reality they aren't. Also: no signs of water ingress / dampness under the carpets where many of the electrics are routed.
Before you ask: the car is an immaculate, cherished 135k mile 2004 facelift S320L cdi running on standard 17" alloys with newish OE 225/55 94W rated Continental tyres at the correct pressures. It drives perfectly straight, has new OE front suspension arms etc, connectors to struts checked for corrosion, airmatic ECU swapped for a used / tested one, sensor readings all within range etc. - I could go on & on. Only to say that after 5 years the problem persists. Another clue: the new OE suspension arms have been replaced AGAIN after only 14k miles since last done due to being 'mashed' (my helpful local Mercedes Indie says they should last approx 40k miles in normal driving conditions, and I'm a gentle driver). Evidence enough that I'm not imagining the problem? (I know S Classes well as a former MB sales exec & latterly head office training consultant on many Ride & Drive events - 'Magic Carpet' Ride & all that?) .
John Daly (here - thanks) kindly suggested that a 'hidden' bad connection to / from a relay, SAM or other electrical component in the ADS system might be causing the ECU to shut-down the ADS into Hardest / Level 4 Safety mode - but without throwing a code on SDS or any warnings on the instrument cluster. When I first had the car there was a brief 'burning rubber' smell in the cabin: never to be repeated, but at the same time the cause has never been never found. Strange or what?!
All thoughts & suggestions welcomed from any W220 owners who've had similar 'mystery / hidden' (i.e. no SDS fault codes) electrical problems - or any Mercedes Techies who might be tuning in? Or.. would anyone in the South / South West with a 'healthy' (airmatic / ADS wise) W220 of any variant like to meet-up and drive my car / give me their opinion on the hard damping problem? (I'll be happy to travel to you & buy lunch in appreciation).
Thanks all
Mark B. (Bristol area)
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