Recently I brought my car in for some issues with the sound. The sound would "bounce" or "cut in and out" from side to side and front to back in the car by itself (not anything related to the VSS/Speed Sensitive). As well as the door trunk button rattle, and rear speaker grill.

The dealership said there was a COMAND/NAV and AMP update for my system (Harmon/Kardon) that updates the MOST fiber system and some other things. Since then the sound quality in the car is terrible, here are the issues.

2005 C55 AMG

1. Mid thru Bass seems lacking now (mid's and bass were perfect before update)

2. Highs seem to be over powering and ear piecing (prior to update everything was balanced)

3. Sub woofer seems very low and lacking now (was getting strong bass response prior)

4. I have and error code in the COMAND "DTC135,count 1,pas" does that mean anything?

I have tried tuning the sound back to the settings I had for Bass, Treble, fade, and sound in the system and it still sounds "empty" or lacking. Is here something else I can check? And Fuses that might have blown?

I checked COMAND Service menu. I also tried playing with the EQ via COMAND "Flat/Active", and the LOUD setting "on/off" both of these items dont really seem to do anything. What does GAP do in the COMAND?

Also How do I adjust the VSS or Speed Sensitive volume setting, and is there any where else I can adjust the EQ? On the AMP, Via STAR?

Could the amp or another piece be broken?

Is there a way to stop the rear grill and trunk button rattle.

I had a BOSE system in my prior car C230 and it was awsome , this Harmon/Kardon system does seem as great.

Any help is appreciated.

Try and perform an initial startup on the amplifier or also the headunit.

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www.benzmodz.com .... putting the Me into Mercedes.

I suspect dealership updated the firmware in the Harmon Kardon amplifier and then did not code it to tell it what car it is in (they have some sound equalisation paramaters that are set for the car since the amp is used in multiple models but each is a different interior shape, even the old COMAND 2.0 has these)

Ask them to check the coding, or better still go through the initial startup sequence on the amp and the COMAND.


Richard

[edit, sorry, duplicated what Benzmodz advised]

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Of course i'll take it apart.

www.mercupgrades.com
http://www.comandonline.co.uk

How do I go through the initial start up sequence on these? Is that the option to reboot in the service menu? or is this something else?

Or is this something the dealer can only do? I get some bass from it but i have to turn the bass from 0 to all the way to the right to get something decent, the audio all around sounds terrible.

Is there a way to back out the updates they made???

What does this error code mean in the COMAND - Error code in the COMAND "DTC135,count 1,pas" ????

The Diag screem shows W203 is that what you are referring too?

It has to be done from Star Diagnosis ..

You can not back the updates out.

So, I'm afraid its "get the dealer who updated it to fix it" - suggest that they do initial startup on the HK AMP and then check the HK amp coding, and check the coding of the other MOST units.
(They should understand that)

Richard

__________________
Of course i'll take it apart.

www.mercupgrades.com
http://www.comandonline.co.uk