W220 Airmatic / ADS Harsh Damping (HD) Problem: Help please?!

[markben]

Greetings all. Apologies for this long post, but please read-on & you might understand the reason for my latest enquiry?

I have a long-term ‘mystery..’ ADS Hard Damping (HD) issue with my otherwise immaculate & well maintained (regardless of cost) 7-year owned now 140k mile 2004 W220 S320L cdi.

The HD Symptoms:

In ‘Comfort’ mode, the ADS seems (correction: IS!) ‘Stuck’ in any or all of Sport 1, Sport 2 or even Level 4 Hard Compression & Rebound ‘Driving Safety’ setting at all 4 struts & damping valves 95% of the time, with a rare, random, momentary but dramatic softening (‘Magic Carpet’ - as it should be). The ride / damping quality is usually truly atrocious over even minor road ruts & ridges at low speeds (HARD BUMP / THUMP - OUCH!). Otherwise, the car maintains an even ride height & level with never any ‘dropping’ at any corner (so leaks ruled out?).

Investigations & Repairs to date:

4 x new Mercedes supplied Reman struts, Valve block, Airmatic compressor + relay + air filter, 3 x level sensors, rear axle ABS sensors & reluctor rings (all new OE at massive expense). Plus.. the Airmatic ECU swapped twice for used / tested units. But ALL with ZERO improvement.

(Before you ask!: the car runs on near perfect un-damaged OE 17” Mismar alloys with new 225/55 x 17” 94 rated Continental tyres (not run-flats) at the correct pressures, never any Mods, drives perfectly straight, all other suspension components (arms, bushings etc) recently replaced with OE, full Romess alignment done).

Various local MB Indies (un-named for obvious reasons), my main dealer, and an intrepid (but terminally puzzled) local Auto Electrician in SW England have failed to identify the cause of nor fix my HD problem despite my ‘cost no object’ approach. Worse still, a couple of Indies claim ‘It rides ok’ after ‘No faults’ stored on Dx kit (e.g. SDS). I won’t comment further..

My Best Guess & Suspicion (after all of the above being eliminated): the HD problem is most probably due to an intermittent (but catastrophic in terms of damping softness) electrical fault in the wiring harness or connections in the Airmatic / ADS circuitry - which is probably due to something as simple as a corroded / burned / shorted connection somewhere… whereby the ECU defaults to Level 4 ‘Hard Compression & Rebound’ setting at all 4 struts simultaneously as a safety precaution to maintain even & level ride height (i.e. very / too stiff). Another Clue: when I first owned the car, there was a one-off, brief but strong 'burning' (electrical shorting?) smell inside the cabin when switching-off the engine. But the cause was never investigated nor diagnosed by Indies nor my AE despite my mentioning it. Again...

So, my Big ‘Ask’: can anyone here recommend an MB Indie and / or specialist Auto Electrician who:

• Has specialist knowledge & experience of working with these types of ‘mystery’ electrical problems on similar Airmatic / ADS equipped cars?
• (As / more Important!): has the expertise, patience & tenacity to ‘Dig Deep' into my HD problem?

As mentioned: ‘money / expense no object’ for a dedicated & interested Indie and / or Auto Electrician who is willing & able to take-on my ‘mystery’ HD challenge - and FIX IT (!) after 7 long years. If it means having my car for a week / stripping down & forensically testing / examining the relevant electrical parts / my travelling across the UK to him / them, I’m prepared to do it.

But.. as you might understand.. I need to be absolutely confident in any recommended Indie and / or Auto Electrician after so many disappointments with others.

Thanks for patiently following my HD saga, looking forward to your thoughts & suggestions.

Mark B. (Bristol area).

 

[markben]

Greetings all. Apologies for this long post, but please read-on & you might understand the reason for my latest enquiry?

I have a long-term ‘mystery..’ ADS Hard Damping (HD) issue with my otherwise immaculate & well maintained (regardless of cost) 7-year owned now 140k mile 2004 W220 S320L cdi.

The HD Symptoms: In ‘Comfort’ mode, the ADS seems (correction: IS!) ‘Stuck’ in any or all of Sport 1, Sport 2 or even Level 4 Hard Compression & Rebound ‘Driving Safety’ setting at all 4 struts & damping valves 95% of the time, with a rare, random, momentary but dramatic softening (‘Magic Carpet’ - as it should be). The ride / damping quality is usually truly atrocious over even minor road ruts & ridges at low speeds (HARD BUMP / THUMP - OUCH!). Otherwise, the car maintains an even ride height & level with never any ‘dropping’ at any corner (so leaks ruled out?).

Investigations & Repairs to date: 4 x new Mercedes supplied Reman struts, Valve block, Airmatic compressor + relay + air filter, 3 x level sensors, front body vertical acceleration sensors (2), rear axle ABS sensors & reluctor rings (all new OE at massive expense). Plus.. the Airmatic ECU swapped twice for used / tested units. But ALL with ZERO improvement.

Before you ask (!): the car runs on near perfect un-damaged OE 17” Mismar alloys with new 225/55 x 17” 94 rated Continental tyres (not run-flats) at the correct pressures, never any Mods, drives perfectly straight, all other suspension components (arms, bushings etc) recently replaced with OE, full Romess alignment etc.

Various local MB Indies (un-named for obvious reasons), my main dealer, and an intrepid (but terminally puzzled) local Auto Electrician in SW England have failed to identify the cause of nor fix my HD problem despite my ‘cost no object’ approach. Worse still, a couple of Indies claim ‘It rides ok’ after ‘No faults’ stored on Dx kit (e.g. SDS). I won’t comment further..

My Best Guess & Suspicion (given all of the above): the HD problem is most probably due to an intermittent (but catastrophic - in terms of damping softness) electrical fault in the wiring harness or connections in the Airmatic / ADS circuitry - which is probably due to something as simple as a corroded / burned / shorted connection somewhere… whereby the ECU defaults to Level 4 ‘Hard Compression & Rebound’ setting at all 4 struts simultaneously as a safety precaution to maintain even & level ride height (i.e. very / too stiff).

Another Clue: when I first owned the car, there was a brief but strong, one-off burning / electrical? smell in the cabin when switching-off the engine. But the cause was never investigated nor diagnosed by various Indies nor my AE - despite my repeatedly mentioning it. Again..

So, my Big ‘Ask’: can anyone here recommend an MB Indie and / or a specialist Auto Electrician who:

• Has specialist knowledge & experience of working with these types of ‘mystery’ electrical problems on similar Airmatic / ADS equipped cars?
• (As / more Important!): has the expertise, patience & tenacity to ‘Dig Deep' into my HD problem?

As mentioned: ‘money / expense no object’ for a dedicated & interested Indie and / or Auto Electrician who is willing & able to take-on my ‘mystery’ HD challenge - and FIX IT (!) after 7 long years. If it means having my car for a week / stripping down & forensically testing / examining the relevant electrical parts / my travelling across the UK to him / them, I’m prepared to do it.

But.. as you might understand.. I need to be absolutely confident in any recommended Indie and / or Auto Electrician after so many disappointments with others.

Thanks for patiently following my HD saga, looking forward to your thoughts & suggestions.

Mark B. (Bristol area).

 

[DSK]

I see this is a new thread. I am sure I saw one recently for the same issue on this forum where the problem was solved by (iirc), some new electrical connectors of some sort near the top of the of the suspension struts.

HTH


Sent from my iPhone using Tapatalk

 

[DSK]

I posted the same in your duplicate thread;

I see this is a new thread. I am sure I saw one recently for the same issue on this forum where the problem was solved by (iirc), some new electrical connectors of some sort near the top of the of the suspension struts.


Sent from my iPhone using Tapatalk

 

[markben]

I see this is a new thread. I am sure I saw one recently for the same issue on this forum where the problem was solved by (iirc), some new electrical connectors of some sort near the top of the of the suspension struts.

HTH


Sent from my iPhone using Tapatalk

Thanks DSK, apologies for the duplication.

 

[V6Matty]

Here’s the thread, looks like you’d been following it too,
Post in thread 'W220 Airmatic continuing HD (‘Hard Damping’) problem / Help please?!'
https://forums.mercedesclub.org.uk/...ping’-problem-help-please.198784/post-2078844