Rear SAM
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Junior Member
Joined: Dec 2013
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W221 S600
Rear SAM
My Comand has no sound, had car scanned, test shows fault Rear signal acquisition and actuation module, Communication on the MOST bus is faulty, MOST bus reports open ring, the software release of control unit "Rear SAM" is not up-to-date.
is this the Harmon amp, i know rear SAM is in the boot but how do i access rear SAM to check fuses.
thanks
is this the Harmon amp, i know rear SAM is in the boot but how do i access rear SAM to check fuses.
thanks
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From: Europe
223.168 & 213.012 & 906.633 & 214.005
Rear SAM is the fuse box behind the arm rear armrest. See your owner's manual.
The MOST communications issue cannot come from the rear SAM, the MOST fibre ring does not pass the rear SAM. Of course if the rear SAM does not provide power to some of the MOST devices, you could get that error.
If the car has been diagnosed with a Star tool, it would be good to have the exact fault codes.
The MOST communications issue cannot come from the rear SAM, the MOST fibre ring does not pass the rear SAM. Of course if the rear SAM does not provide power to some of the MOST devices, you could get that error.
If the car has been diagnosed with a Star tool, it would be good to have the exact fault codes.
Out Of Control!!
Joined: Jul 2003
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From: North Scottsdale, AZ
'71 Pinto
You can check f122 (COMAND controller) located behind left trunk panel http://workshop-manuals.com/mercedes...ar/page_14823/ if fine, as DB suggested for definitive diagnose have someone pull fault codes with MB DAS.
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From: Grays Harbor
S550 2012 & 2011 E550 4Matic
Out Of Control!!
Joined: Jul 2003
Posts: 15,901
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From: North Scottsdale, AZ
'71 Pinto
Components (radio, amp, etc.) are arranged within a closed MOST (fiber optic) loop. D104 = position (device) 4 so you need to identify this unit. Xentry (MB diagnostics) will should give device. DIY, you will need a fiber optic bridge (bypass) to remove each device one at a time from loop to confirm which is malfunctioning.
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Junior Member
Joined: Jun 2014
Posts: 42
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From: Grays Harbor
S550 2012 & 2011 E550 4Matic
Components (radio, amp, etc.) are arranged within a closed MOST (fiber optic) loop. D104 = position (device) 4 so you need to identify this unit. Xentry (MB diagnostics) will should give device. DIY, you will need a fiber optic bridge (bypass) to remove each device one at a time from loop to confirm which is malfunctioning.
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MBWorld Fanatic!
Joined: Aug 2014
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S500
I'd caution against updating the rear SAM... it brings in bugs as they flash with facelift software that they shouldn't. My diagnostics also complains its not suitable (autel) if it wasn't for the bugs I'd say autel are wrong but sadly it seems a third party understands the car better than the manufacturer
if you have an issue with no station names or frequency displaying on the radio when you lose sound, its always a dead amp (its a more reliable failure than expecting the sun to come up tomorrow)
if you have an issue with no station names or frequency displaying on the radio when you lose sound, its always a dead amp (its a more reliable failure than expecting the sun to come up tomorrow)
Junior Member
Joined: Jun 2014
Posts: 42
Likes: 2
From: Grays Harbor
S550 2012 & 2011 E550 4Matic
I'd caution against updating the rear SAM... it brings in bugs as they flash with facelift software that they shouldn't. My diagnostics also complains its not suitable (autel) if it wasn't for the bugs I'd say autel are wrong but sadly it seems a third party understands the car better than the manufacturer
if you have an issue with no station names or frequency displaying on the radio when you lose sound, its always a dead amp (its a more reliable failure than expecting the sun to come up tomorrow)
if you have an issue with no station names or frequency displaying on the radio when you lose sound, its always a dead amp (its a more reliable failure than expecting the sun to come up tomorrow)
Thanks for the pointers.
Junior Member
Joined: Jun 2014
Posts: 42
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From: Grays Harbor
S550 2012 & 2011 E550 4Matic
Thanks Botus, I really appreciate the communication.
Junior Member
Joined: Jun 2014
Posts: 42
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From: Grays Harbor
S550 2012 & 2011 E550 4Matic
Cheers Mate.
Junior Member
Joined: Aug 2020
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From: Hyderabad, Telangana
EQC, S Class Extended, Grace CVT.
Components (radio, amp, etc.) are arranged within a closed MOST (fiber optic) loop. D104 = position (device) 4 so you need to identify this unit. Xentry (MB diagnostics) will should give device. DIY, you will need a fiber optic bridge (bypass) to remove each device one at a time from loop to confirm which is malfunctioning.
Newbie
Joined: Feb 2024
Posts: 2
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Mercedes S550
Thanks Botus. Yes indeed, I used an Autel scanner which gave me the D104 position 4 code. And when I lose sound the radio station identifier / frequency and name do disappear. I have ordered the MOST jumper and will check the other components, which seem to work when I do have sound. I guess my next option is to get it checked by a Star scanner before I start changing or getting pars repaired.
Thanks for the pointers.
Thanks for the pointers.
MBWorld Fanatic!
Joined: Aug 2014
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S500
the dealer needs shooting - with the trim out the way - it takes seconds to loop out a Sirius module to test their wrong theory
dead modules give issues - but a dead amp give no sound and no station display on FM - a dead amp is as likely as a empty fuel tank - a dead lingatromic or sirius module is as likely as your 7th puncture
dead modules give issues - but a dead amp give no sound and no station display on FM - a dead amp is as likely as a empty fuel tank - a dead lingatromic or sirius module is as likely as your 7th puncture
Newbie
Joined: Feb 2024
Posts: 2
Likes: 0
Mercedes S550
the dealer needs shooting - with the trim out the way - it takes seconds to loop out a Sirius module to test their wrong theory
dead modules give issues - but a dead amp give no sound and no station display on FM - a dead amp is as likely as a empty fuel tank - a dead lingatromic or sirius module is as likely as your 7th puncture
dead modules give issues - but a dead amp give no sound and no station display on FM - a dead amp is as likely as a empty fuel tank - a dead lingatromic or sirius module is as likely as your 7th puncture
MBWorld Fanatic!
Joined: Mar 2005
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From: Wash. D.C.
'20 S63
I’m currently having a similar problem with my s550, I have no sound, or no station list. I recently took it to the dealership, the diagnosed it with error code D104, the told me it was most likely the satellite radio module. I replaced the Sirius satellite radio module, and nothing. I’m thinking about ordering a new amp but I’m also curious as to what other possibilities it could be?
https://www.ebay.com/itm/223136521415
