All Command devices unavailable???

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RobS280

New Member
Joined
Feb 8, 2014
Messages
13
Location
Morecambe Bay - UK
Car
2005 S280
Hi folks, didn't think I'd be pestering for help so soon after joining but I'm about ready to start tearing my hair out :confused:
The Command system on my 2005 S280 tells me none of the devices are available (Radio, CD, DVD, SatNav etc.) then promptly shuts down. This began yesterday after I had to check all the fuses (one by one) because I discovered that the engine cooling fan was failing to operate at high engine temp. In the event, I found that all fuses were ok so the cause of my original problem lies elsewhere. It was immediately after this that I discovered the problem with my audio/video system. When checking fuses I only removed one at a time, then replaced before removing the next. I'm sure this problem with Command (device unavailable messages) is directly related to the fuse check I did, but can't understand why or how to fix the problem?

This afternoon I disconnected the battery for a half hour hoping that this might restart or reset the system, but no luck.. The problem still remains :fail
 
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Recheck your fuses. You may have reinserted one into the space between the correct holder.

Sent from my iPhoney Wonie using MBClub UK
 
Would be great if it turns out as simple as that.
I was very careful replacing them, but I'll double check them all tomorrow.
I also noticed that there's no power to the CD changer in the boot, although there is power to the Nav CD drive above it.

Thanks for the suggestion :cool:
 
The lack of power to the CD changer means the entire fibre optic network is down which is causing your symptoms. As already suggested to you, check the fuses. Start with the one for the CD changer ;)
 
Well fellas, I've done as you suggested.. Double checked all fuses for correct fit, but still no power to eject CD changer and Command says all devices not available, then shuts down. Command was working perfectly up until doing the initial fuse check. Can't understand it and I'm stumped :fail
 
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Since the CD changer Eject button doesn't work, would you think that this is where the fault lies? I'm only now starting to understand a little about MB's fibre optic loop system, but it seems to me that if there's no power to the changer, then the whole system will fail due to the loop being broken. I wonder if anyone has a diagram of the various fuse boxes for the 2005 S series? The complete toolkit is still in the boot, but the fuse box reference card is missing.
 
Have you checked ancillary fuse boxes ? I still think it maybe a fuse related issue.
You really need a multimeter on the job , sometimes visual inspections of fuses can be deceptive. ( not telling you how to suck eggs Rob ).
 
Thanks and no worries Ash, every suggestion is gratefully accepted. I do have a knowledge of electrics/electronics and, but for the awful weather here yesterday and today I would have broken out my Fluke meter. Instead, it was a careful visual inspection. I wish I had a fuse layout so that I could home in on likely areas.

The fuse boxes I've checked are those both sides of the engine bay, and the fuse box under the right rear passenger seat.

I'm puzzled as to why there seems to be no power to eject the CD cartridge yet the SatNav box above it happily ejects and accepts the Nav CD. I half expected both units to be on the same fuse.. Then again, maybe not.

Oh what I'd give for a fuse layout diagram ;)
 
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I'm puzzled as to why there seems to be no power to eject the CD cartridge yet the SatNav box above it happily ejects and accepts the Nav CD. I half expected both units to be on the same fuse.. Then again, maybe not.

Oh what I'd give for a fuse layout diagram ;)

Ahh, let's rewind,

Seen as you have no fuse diagram. If you can remove the changer & check two things

1) 12v & ground present at the power connector
2) is there a red light present at the fibre optic connector ? This will be a two way connector with normally orange coloured hard plastic casing , ( Do not crimp or strain these ) . They will have arrows on the connector one arrow going into to cd changer ( this is the one that should have a red light ) & the other arrow out of the changer to make the most ring.

If you have no led ... Then fibre optic source is broken somewhere else.

Hope this helps Rob.
 
Ahh, let's rewind,

Seen as you have no fuse diagram. If you can remove the changer & check two things

1) 12v & ground present at the power connector
2) is there a red light present at the fibre optic connector ? This will be a two way connector with normally orange coloured hard plastic casing , ( Do not crimp or strain these ) . They will have arrows on the connector one arrow going into to cd changer ( this is the one that should have a red light ) & the other arrow out of the changer to make the most ring.

If you have no led ... Then fibre optic source is broken somewhere else.

Hope this helps Rob.
Sounds a good plan. I'll go do that tomorrow morning and report back.

Thanks Ash :cool:
 
If all else fails give Richard or Alfie a call at Comand (forum sponsors), pretty sure they will be able to sort you out :thumb:
 
Before re-checking the fuses with a meter and ripping the CD changer out, I just thought to check battery voltage. Oh dear.. 9.6 volts standing is obviously WAY LOW! I started the engine and with 1,200 rpm volts rise to 12.4 and gradually more with increasing revs, although Command still reports all devices unavailable, then shuts down.

Is there some kind of under volt protection in these cars that would disable the Command system on battery low volts? But then why am I able to eject the Nav disk yet not able to eject the CD changer?

I've disconnected the battery and stuck it on charge. Whilst that's running, I'll go check the fuses again with the meter as you suggested Ash.
 
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Different model in my case, but slightly similar. Day 2 of ownership (at 7.30am on top of the A66 :crazy:) the car went into progressive shutdown. Comand was first (followed by ABS and then the one that got my attention - red brake about to fail). Turned out the boot battery was completely shot and had obviously been on mega charge the afternoon before when I collected it.

New battery fitted, all was well again, so from what you say, good chance it's the battery
 
Different model in my case, but slightly similar. Day 2 of ownership (at 7.30am on top of the A66:crazy: ) the car went into progressive shutdown. Comand was first (followed by ABS and then the one that got my attention - red brake about to fail). Turned out the boot battery was completely shot and had obviously been on mega charge the afternoon before when I collected it.

New battery fitted, all was well again, so from what you say, good chance it's the battery
Top of the A66 with that load of faults.. I bet that was a fun experience :eek:

Given what you describe, it's looking like the battery might be the culprit. It's a long time since I last saw a battery produce such low volts. Hadn't heard of "progressive shutdown" before, but it now makes some sense.

I'm beginning to wonder what the normal current draw on the battery should be with the ignition key removed. I don't want to buy a new battery only to find there's a short somewhere :(

Best case scenario for me would be.. battery is DUFF and all else is ok. "PLEASE" :wallbash:

Listen fellas.. Thanks for all your input so far. It's good to have help, advice, and ideas in a situation like this. I'll try the re-charged battery tomorrow and get back to you :cool:

Rob
 
Something has just occurred to me. On many MBs there are fuses behind the panel on the end of the fascia, with a fuse diagram neatly folded inside it.

Open the driver's door and look at the end of the dashboard. If there is a removable panel there, remove it and you may get lucky.

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Thanks for that (and the photo) Stratman. I can't seem to be able to prize the end cover off and was afraid of cracking or breaking it, so perhaps there's no fuse box on this model (2005 S280)

I've failed miserably so far. I charged the battery overnight and it's sitting at 12.9 volts now. Then I reconnected it, but still have no Command ("System unavailable"). Fuse 61 under the right rear passenger seat supplies the CD multichanger and the fuse is fine (tested with multimeter).

Just to clarify how this problem started..

1. All Command devices had previously been working perfectly.

2. I discovered that the engine cooling fan wasn't running, even at high engine temperature, and so thought I'd check the fuse before anything else.

3. Had no idea which fuse supplied the fan, so I had to visually check all the fuses in the box under the bonnet (driver side), and the fuses in the box under drivers side rear seat. I removed each fuse in turn, then replaced each before moving on to the next.

4. After re-fitting the last fuse I started the engine and noticed right away that the Command system was displaying the message "Sytem Unavailable" and after about 10 seconds, it shut down. I also found that I couldn't eject the CD Changer in the boot. It's been this way ever since.

How could simply pulling a fuse then re-fitting it result in all of this?
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Ash suggested, I pull out the CD changer and check for 12volts and ground, and also check for optical signal to and from the unit. It's the logical next step I think, but not sure how to go about removing the bugger?
 
From what your saying ,my guess is you've possibly caused a spike in the electrical circuit when you was checking fuses.

1)So have you checked each fuse @ every fuses box location for your car with a multimeter? How are you checking? With ignition off or on?
2)I'm not a Mercedes mechanic but if you have an auxiliary battery fitted which I know the latter S class do , is that still feeding the command system when you have disconnected the main battery?
My thinking on this is, I know the Aux battery is there for the likes of electric handbrake but is it still feeding circuits like the command system , where the gremlin lies? So when you think you've reset the command by disconnecting the main battery you haven't really?!... I'm only assuming here so if we have anyone with further knowledge then please correct me on my post to help Rob.

Ideally get a star diagnostic check that can point the direction of communication breakdown & can clear an error.

Your changer should either come out with special stereo type removal keys or the Glovebox requires removing .

Go through the logical steps above Rob, as you say everything was working fine before you fuse checked . That multimeter is a good start. I've got a feeling it's something simple that is getting overseen here. ( something I've seen happen to me endless times ).
 
From what your saying ,my guess is you've possibly caused a spike in the electrical circuit when you was checking fuses.
Yep, a "current spike" occurred to me too Ash. Since the head unit obviously has power, but the Multi-CD changer in the boot doesn't, my suspicions point to the changer. On my car, fuse 61 supplies the changer. If it also supplies the NAV unit above it which still has power, then perhaps there might be an internal fuse in the changer which might have blown due to a spike. That would explain fuse 61 still being ok, and also the NAV unit still being ok. Sheesh! I hope that makes sense.

As you said earlier, it's not always obvious that a fuse has blown so I've tested them all with a continuity test.. they're all fine.

I'm not aware of the car having an auxiliary battery, and certainly can't see one. There's no mention of one in the Owners manuals either.

I'm 40 miles from the nearest MB dealer and I don't know if Star diagnostics cover the Command system. If absolutely necessary then I'll just have to try the dealers. Just so frustrating because, as you say, it's probably something obvious I'm overlooking :confused:

Going to have to get that Multi-changer out and have a look at the cables etc.

Thanks for your ongoing help Ash, it's much appreciated :cool:
 

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