MB Medic Mercedes-Benz Repair Guides, Service, How To DIY
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This article will show you how to remove the COMAND Stereo Radio and CD player/changer, which is necessary if you want to replace, upgrade or install a new head unit (HU). If your stereo stops working, replace it with another OEM head unit or install an aftermarket stereo that features DVD, a rearview camera, Bluetooth, and Navigation. A list of alternative head units that you will find on Amazon that will fit your Mercedes-Benz E-Class W211 / CLS W219 is listed at the end of this DIY article.
Note that if you go with an aftermarket route, you may lose a few features, such as controlling your stereo with the steering wheel buttons. If you must have steering wheel controls to change the radio, you need a CANBUS module. Because Mercedes-Benz uses a D2B fiber optic bus, installing an aftermarket unit is slightly more complicated than in other cars.
Instructions apply to:
Mercedes Benz E Class W211
Mercedes Benz CLS Class W219
Tools & Parts Needed
- Replacement Head Unit (see List of Recommended Alternatives Below)
- Torx Bit Set
Instructions on how to remove the COMAND Stereo Head Unit
Disconnect the battery before you start. The head unit, the fiber optic ring and the switches in the console are all live with the key out, and a dropped Torx bolt or a slipped trim tool across a connector is a lot cheaper to fix if nothing is powered.
Step 1
Remove the shifter handle and the wood trim on the center console. You can remove the trim by lifting it. It is easier with the shifter knob off, but you can do it either way. The trim will not clear the lever while it is in Park, so the shifter has to be moved down to D with the engine off. Before you move it, understand what that does: out of Park the transmission is no longer holding the car and the parking brake is the only thing that is. Do this on level ground, set the parking brake firmly, and chock a wheel before the lever moves.
Step 2
Remove the ashtray. You may have two screws or a locking tab holding the ashtray. On the back of the ashtray, you will see electrical wires behind the cigarette outlet. Unplug the electrical connector. 
Step 3
Remove the CD changer or storage compartment if you don’t have a CD changer. If your car has heated seats, this part has your Hazard Button, door lock/unlock switch, ESP, and heated seat buttons.
Step 4
Once you remove the CD changer, you can access two bolts at the bottom of the COMAND head unit. These two bolts have Torx heads. You must get the bolts loose; they can not be removed completely. Unscrew them until they stop rotating. They are long, and you must turn them over 30 times to unlock the HU. Pull out the HU and unplug the fiber optic cable from the back of the COMAND A40/3 unit.
If you are replacing or upgrading with an OEM Mercedes-Benz head unit, the dealer’s Star Diagnostic (XENTRY) can retrieve the settings from the old unit and transfer them to the new unit. If you don’t have access to it, you will need to set the new settings manually. Either way, a full system scanner such as the UCAN-II Pro will read and clear the fault codes a head unit swap leaves behind and show whether every module on the D2B fiber optic loop is communicating.
Video on how to remove the COMAND, Stereo Head Unit
The fiber optic ring, and why the rest of the system can go quiet
The point the intro makes about D2B fiber optics is worth expanding, because it is where most of these jobs come unstuck. The optical bus is a ring: the signal leaves the head unit, passes through every other device on the bus in turn, and comes back. The amplifier, the CD changer, the phone module and the voice control module are all links in that chain. Break the ring at any point and the devices on it stop talking, which is why pulling the head unit out and leaving the two fiber ends hanging can leave you with no sound at all rather than just no radio.
Two practical consequences. If the head unit is coming out and not going straight back in, the ring needs closing again, either with the replacement unit in place or with a loop that joins the two ends so the rest of the devices still see a complete circuit. And if you fit an aftermarket unit that is not on the optical bus at all, the other modules on the ring have to be accounted for rather than simply abandoned, which is the part of an aftermarket conversion people underestimate. That is a separate job from the removal described here and worth settling before the console is in pieces.
Handle the fiber ends carefully while they are out. They are glass or plastic optical fiber, not copper, so a tight bend, a scratched end face or dirt on the tip degrades the signal, and the fault that follows looks electrical and is not. Leave the caps on if the connectors came with them, and keep the ends off the carpet.
COMAND Head Unit Alternatives
If you want to upgrade your head unit, consider the Mercedes E-Class CLS W211 W219 Comand APS NTG 2.5
. This unit has: a single CD/DVD player, a high-definition LED display model, Bluetooth built-in, and an SDHC card with up to 32GB compatibility.
Detailed Description:
- Widescreen format 16:9 6,5″ TFT HD LED High definition color screen (much better & higher resolution, much better picture quality)
- Internal 40GB Hard Disc drive for navigation maps, MP3, and other media
- Single CD/DVD Player
- Bluetooth for the phone
- Linguatronoc ((voice control, voice recognition))
- DVD movie, MP3, audio CD Player
- DOLBY DTS sound processor
- 2D, 3D LIVE map display with TMC and POSTCODE search, Split-Screen-Function
- Possibility of connection for mobile, amplifier, TV-tuner, DVD/VIDEO-player, PlayStation, etc.
- Supports an external Harman Kardon amplifier
Recommended Aftermarket Head Units for E-Class E211 and CLS W219
If you are replacing your COMAND head unit with an aftermarket stereo, here are a few alternatives you may want to consider. Any of these stereos can be purchased on Amazon; links are provided.
For a clean-looking install, you will need Frame DVD Dash Installation Surrounded Trim Kit for E-Class CLS-Class.
Application
E-Class W211 with any of the following head units (HU):
-COMAND APS with CD Player, DVD, or Navigation
-COMAND Head Unit without navigation and CD Changer
The COMAND system may also be referred to as unit A40/3.
COMAND System / Navigation / Stereo / Radio / Head Unit Part Number
| A 2118276342 | A 2118700289 | A2118204397 |
Before you buy parts, scan every control module, not just the engine. It shows the root fault behind the warning lights and tells you whether the problem is still active. See how to do a full health check.
