Mercedes COMAND Diagnostic ( � Service � ) Mode

 

Version 1.6 10 Dec 2008 – Add more info about interlocks

Version 1.5 7th October 2007 – Add info about Comand 2.5

Version 1.4 12th May 2007 – Correct links for new mercupgrades website

Version 1.3 25th March 2006 – correct CTEL2 value

Version 1.2 25th March 2006 – tidy up

Version 1.1 25th March 2006 – add �exit� instructions

 

 

Introduction.

 

Mercedes� COMAND 2.0 (i.e. CD based COMAND) system has a whole set of hidden diagnostic menus.

 

Diagnostic mode is also available on COMAND 2.5 (the original S/CL class COMAND version with a tape deck) but will be subtly different to those described below.

 

These menus are useful when trying to ascertain if there is a fault with your COMAND system, however, nothing can be altered from these menus.

 

To enter diagnostic mode, press SYS and then select the AUX input by turning the right hand rotary knob to highlight Aux and pressing the rotary knob.

 

Then hold down the following 3 keys for about 10 seconds. MUTE, 1, 3

 

(NB, on the Comand 2.5 do this in TV mode as there is no AUX mode)

 

You will then see the following screen: -

 

 

 

On COMAND 2.5 (old S-Class/CL units), it may be possible to enter this menu if you select TAPE input as there is no Aux input.

 

The rest of this document describes what information is in the various screens/menus that can be access in Service Mode.

 

The RET key acts as a �previous screen� key – so to exit service mode, just hit the RET button when the menu above is showing.

 

 

VERSIONS menu

 

Entering this menu allows you to see the software and hardware versions of COMAND.

Select the menu you want with the right hand knob, and use RET key to go back to the previous menu list.

 

Here is an example from the Processors menu, this is a COMAND 2.0 E class unit with the MY2001 software update applied

 

 

The most useful screen here is �Infos� as it tells you if the vehicle is seeing the speed impulse and how many satellites are being received. If you have a different looking Infos menu, it is because you have not applied the MY2001 software update to COMAND – which you should so.

 

 

 

 

TUNER menu

 

This returns you to the FM/AM main screen, but also shows an extra line showing the currently tuned stations frequency and signal strength (0-10). Remember that in Europe the main line normally shows the RDS station name.

 

 

DIAGNOSIS menu

 

This allows you to see various configuration items, including the error list, to reset the COMAND system, and to look at the D2B status.

 

 

 

The Error list initially shows the list of errors that the dealer�s Star Diagnosis machine would see, holding MUTE and 1 switches to the internal list. MUTE and 4 returns to the original list, MUTE and 0 clears the error list.

 

 

The meaning of the SAE-Code in the error list can be found at: -

 

Mercupgrades.com COMAND error codes

 

The Type field is part of the error code, and in the list of error codes is shown after the / in the error code – For instance B1912/8 would have B1912 in the SAE-Code column and 0x0008 in the Type column.

 

The Cnt figure is useful as it tells you how many times an error is occurring. The State value tells you whether the fault has happened Previously or if the fault is currently Active.

 

Selecting System Reset resets the COMAND unit.

 

The D2B components list shows what is Actually found on the fibre optic bus, and what the system is Configured on the bus. If the unit has

been properly configured by the Mercedes dealer, then these should match each other, and match what extra options you have in the vehicle.

 

 

The 3 digit numbers shown are: -

1C8 COMAND

108 Digital BOSE AMP

190 CD Changer

0F0 Phone

0F1 CTEL2 (e.g. 2nd phone in S class)

1F8 Voice Recognition

1B0 Satellite Radio Module (USA)

0E0 Teleaid Control Module (USA)

 

 

CONFIGURATION menu

 

This shows how various options are configured on the COMAND system.

 

 

There are various tickboxes,

TV-Tuner TV tuner is enabled – enables TV button on US units

Telephone (expand) Enables SMS functionality on phones

Telematic Enables TCS (nothing to do with TMC)

Telematic over D2Bditto

Analogue Bose Tells system analogue bose amp connected

Combi-Self-Aligned Tells COMAND whether the instrument cluster will self centre any text that is sent to it or not

 

And, on the bottom line is 6 alpha-numeric digits (hexadecimal) (20 6D 04) in the above case - The last digit (4) in the above example configures which interlocks are in place to prevent the TV being watched whilst the vehicle is in motion – the other digits control various features, some of which are in the tickbox list.

 

Here is a table of what some of those interlocks mean.

 

First Byte (20 hex in above)

Bit 7 (MSB) Analogue BoseBit 6 SMS Sending disabledBit 5 Always SetBit 4  Bit 3  Bit 2  Bit 1 Telematics (EU) / Starguide (USA)Bit 0 (LSB) TV tuner

 

Second Byte (6D hex in above)

Bit 7 (MSB) Telematic via D2BBit 6 Telephone with expanded functionsBit 5 Instrument cluster with self centering

text (combi self aligned)Bit 4  Bit 3 Always SetBit 2 Always SetBit 1  Bit 0 (LSB) Always Set

 

 

Third Byte (04 in above)

Bit 7 (MSB)  Bit 6  Bit 5  Bit 4  Bit 3 TV disabled at speeds > 10km/h

Bit 2 TV disabled at speeds > 2km/hBit 1 TV disabled if not in Park / NeutralBit 0 (LSB) TV disabled if handbrake off

Also on the bottom line is the setting telling the COMAND how many impulses per wheel rotation the car will send the COMAND unit, this is also in hexadecimal, so 30 means 48. Remember that with some cars the speed is sent over the car�s network (CANbus) rather than with a speed signal wire, so in some cars this can be set to 0.

 

Here is a list of the DTC (error) codes that COMAND can generate. These can be seen via the hidden diagnostic menu.

 

B1000 Control Unit A40/3 (COMAND) is faulty

B1002 Internal CAN databus error (RB Can)

B1003 Interior CAN databus error (CAN B)

B1010 The supply voltage of the control unit is too low

B1730 Excess temperature of CD player

B1734 No speed pulses from traction control module

B1736/1 Fault in reading CD-ROM drive – general CD read error, navigation CD unreadable

B1736/2 Fault in reading CD-ROM drive - CD data block read fault. (may not need to replace unit)

B1736/4 Fault in reading CD-ROM drive – read error CD timeout reading data block

B1736/8 Fault in reading CD-ROM drive – Check CD in player (may not need to replace unit)

B1736/16 Fault in reading CD-ROM drive – Check CD in player (may not need to replace unit)

B1738/1 Navigation Fault: GPS report not received

B1738/2 Navigation Fault: GPS aerial short to positive or ground

B1738/4 Navigation Fault: GPS aerial open-circuit

B1761 Cable fault: short circuit of switching line Ant ON

B1762 Fault in CAN communication with A40/3n2 (Navigation processor)

B1765 Component A40/3 (COMAND) is faulty

B1766 Lost Navigation data

B1767/0 Navigation parameter missing – number of teeth of ABS pulse rotor not configured

B1767/1 Navigation parameter missing – wheel size / height ration

B1769/4 Internal traffic data memory: Function software – Fault

B1769/010 Internal traffic data memory: Fault in communication with CTEL or Teleaid

B1779 Fault in CAN communication with TV Tuner

B1780 Fault in CAN communication with Instrument Cluster

B1795 Fault in CAN communication with EIS control module

N1111/x No data transfer between D2B master and D2N component. The component at location x reports a fault in the D2B ring

N1112 No data transfer between D2B master and D2B predecessor component possible

N1113 No D2B data transfer possible, position can not be located

N1114 Address initialisation of the D2B master faulty

N1115/x A D2B component could not be integrated in the system – The component at location X reports a fault in the D2B ring

N1116/x Failure of D2B component in position X in D2B ring

N1132 At least one button is sticking for longer that 120 seconds

N1141 Set/Actual configuration of D2B ring differs

N1204/1 Telephone fault with dynamic navigation -No GSM signal detected

N1204/2 Telephone fault with dynamic navigation -No portable recognised

N1204/4 Telephone fault with dynamic navigation -No PIN entered

N1204/8 Telephone fault with dynamic navigation – Directory fault

 

Note, N1204/xxx errors are only logged if TCS has been enabled (i.e Telematic Via D2B in the configuration register), and will be logged if the phone has been disconnected etc.

 

 You need to firstly remove the wood (or metal) centre console trim,

The pictures below are for the pre MY2005 facelift, however the procedure is the same on newer cars except that you must open the cupholders, remove the front piece and close them again.

On MY2009 cars to remove the COMAND you must also remove the airvents above to access the screws that hold the top of the COMAND unit.

 

Firstly remove the trim either side of the centre console.

Lower the seats to the lowest and most rearward position to give best access, and then remove the trim which just pulls off from the centre console and then slides out from the dashboard. Put your fingers under the trim (above the carpet) in the middle and pull gently to release the middle clips, work your way backwards until all the clips are released and then pull the trim out (pulling to the rear of the car away from the dashboard).

Here is a picture of the trim removed, circled are the hooks that hook into the dashboard, you can also see all the clips that hold the trim to the centre console and the other two metal clips that lock it into the dashboard.

Now unscrew the 3x TORX TX20 screws on each side that hold the wood/metal trim to the centre console. The screws are quite long and the screw at the rear end is recessed so a torch / flash-light is useful.

Once that is removed, remove the gear selector knob - move the gear selector to N (ensure the parking break is on and the wheels are chocked), pull up the leather gaitor, rotate the knurled nut 90 degress anti-clockwise and pull the gear knob upward. If the

car has keyless go you must not twist the gear knob or you may break the pins from the start/stop switch that plug into the top of the gear selector shaft. On non-keyless-go cars, twisting the knob as you pull upward helps.

On MY2005 onward cars, open the cupholders and remove the front panel and close them again - this allows the two tabs at the top of the centre console trim (that cover the cupholder screws) to come forward without hitting the cupholders.

Ensure that the ash-tray is closed (remove the insert), and you can then pull up the trim, from the rear, by pulling on it through the hole left by the gaitor.

Pull the whole trim out further by pulling it away from the audio/COMAND unit, the ash-tray does intefere with the gear selector surround, so take care.

Once the whole trim is released you should disconnect the 3 cables (one pulls straight out, two are on rotating clips) from the airconditioning unit, the cigarette lighter power (pulls out at 90 degress to the body of the cigarette lighter) and the purple connector on the gearbox mode selector (W/S, W/S/M button). Also disconnect the two plugs to the roof / mirror selector switch if you want to remove the whole trim, but you can just lay it to the side if just removing the audio system.

You will now see one screw (red in picture below) each side of the cup-holder which hold the cupholder to the frame the COMAND sits it. You will also see two screws (blue) each side of the audio unit which you should undo and remove to remove the audio unit.

On MY2005 - MY2008 the COMAND is held in by the blue screws which also hold the mounting frame in place.

On MY2009 onward COMAND is held in by the cupholder screws and there are two additional screws that screw into the top of the COMAND. To access these screws the vents above COMAND must be removed. This is done by removing the speaker grill above them exposing two screws, undo those screws. There are then two hook catches (one at the bottom of each vent) which can be seen through the vents - these are best released with the Mercedes pulling hook tool which will release and pull the whole vent forward. You can then access the screws that hold the front of the COMAND in from above.

When re-assembling ensure that the wiring does not get caught in the ash-tray mechanism, and that all wires are plugged back in again.