Comand 2.0 map position error

[Mad Mike]

New to the forum, I'm hoping one of you Comand experts out there can please advise me on a problem I now have with my Comand DX in an '03 W203.

When stationary and switching on the Comand from cold, my position on the map is roughly right, but the direction the car is facing is usually wrong on the map. When moving, again my position on the map is roughly right, but the car direction shown on the map is varying all the time, taking excursions off road and randomly in all directions. This scenario continues for about an hour and a quarter of driving and then after this "warm up time", the Comand starts to work properly - back on road and the given position is correct to road junctions.

If switch it off and back on again after a short time, the Comand still works normally. Leaving it switched off for longer periods and I seem to have to go through a warm up time before it works properly.

Typically it receives between 5 and 7 satelites and has, I guess, the latest firmware (MB star display on start up, etc.).

I'm an electronics engineer by profession, working with instrumentation, but not Sat Nav units. My uneducated guess is a fault with the electronic compass/gyro. I'm confident that I have the skills to replace such a component, but am not sure if my diagnosis is right. Also I don't know the make/model of the gyro and where to purchase one. Trying to minimise the length of time the Comand would be out of the car, to have everything prepared beforehand would be helpful. (And not to have to open the unit up initially just to get part numbers etc).

Any advice greatly appreciated.

Kind regards,

Mike

 

[Alfie]

New to the forum, I'm hoping one of you Comand experts out there can please advise me on a problem I now have with my Comand DX in an '03 W203.

When stationary and switching on the Comand from cold, my position on the map is roughly right, but the direction the car is facing is usually wrong on the map. When moving, again my position on the map is roughly right, but the car direction shown on the map is varying all the time, taking excursions off road and randomly in all directions. This scenario continues for about an hour and a quarter of driving and then after this "warm up time", the Comand starts to work properly - back on road and the given position is correct to road junctions.

If switch it off and back on again after a short time, the Comand still works normally. Leaving it switched off for longer periods and I seem to have to go through a warm up time before it works properly.

Typically it receives between 5 and 7 satelites and has, I guess, the latest firmware (MB star display on start up, etc.).

I'm an electronics engineer by profession, working with instrumentation, but not Sat Nav units. My uneducated guess is a fault with the electronic compass/gyro. I'm confident that I have the skills to replace such a component, but am not sure if my diagnosis is right. Also I don't know the make/model of the gyro and where to purchase one. Trying to minimise the length of time the Comand would be out of the car, to have everything prepared beforehand would be helpful. (And not to have to open the unit up initially just to get part numbers etc).

Any advice greatly appreciated.

Kind regards,

Mike

This sounds like a speed pulse fault to me. The characteristics you describe are just the same as when a speed pulse is not present.

On the W203, the speed pulse is fed over the canbus so there is no distinct wire for it.

Did you retro fit this comand yourself? If so, you may have the canbus wired connected incorrectly. You can test this by simply operating the steering wheel buttons to change volume/radio station. If they work, then the connection is fine. Also, if you did retro fit yourself, did you make sure you bought an A203 comand part number and not an A463 part? The A463 comand units although look very similar to an A203 require different wiring.

Let us know and we can help further.

 

[Mad Mike]

Hello Alfie,

Thank you for your time. The Comand came with the car and was working fine. Indeed it still works, but now only after it has been switched on for an hour or so.

I looked through the other posts in the forum about the Comand, got myself into the diagnostics and checked the speed signal is there - matches the speed on the dash. The Comand knows whether I'm in forward or reverse, reads ignition on/off, steering wheel buttons etc. so I assume the CanBus signals are still present.

Just as a note, I borrowed another Map CD from a friend and it is no different. As soon as I drive away the map display updates and continues to update, but with a totally random direction for the car on the map. The satelite signal seems to keep my location roughly right. If you have any more thoughts on this, I'd be very grateful.

Many thanks,

Mike

 

[Mad Mike]

An update for anyone interested; I pulled the Comand out of the car and found the giro is made by Matsu****a and has part number EWTS4F. After much trawling around on the Internet, no luck with finding a replacement or even a spec. for this component, so I reassembled the Comand and refitted it back in the car. To my surprise it then worked fine and has continued to do so for several weeks. However, last night, in the cold weather, it played up again for the first 3 or 4 minutes after switch on until it had warmed up a bit. (Still better than the 45 minutes it was taking before). Same thing as the original fault, you drive away, the cursor position on the screen updates as the car moves, but the cursor heads off in all sorts of random directions off road although the general area on the map is correct. I still suspect the giro is the culprit, but I can't find a replacement.

 

[Dieselman]

Try here:
http://www.onesourcecomponents.com/search/results.htm

The EWTS4 is listed as a compact angular rate sensor, so looks to be the correct item.
Not sure what the F suffix is.

And this might be useful.

http://www.trg.dk/projekter/infati/notat2.pdf

Ahh.. very iterstink..

http://cgi.ebay.de/EWTS4-Winkel-Bes...ryZ31335QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Or here for Uk.

http://www.oraclecomponents.co.uk/part_search.php?q=EWTS4&search=Go!

And

http://www.icsource.com/icsourcewdl/icswdl.aspx?user=corncom&part=EWTS4&Submit1=+Go+

 

[prprandall51]

Or you could install a domestic fan heater under the Comand unit to "pre-heat" the Comand before you use the car on a cold day. You will need a transformer, perhaps taken from an old computer, to power it (wire it in reverse). You could also link it up with a thermostat from a central heating system and a timer of some sort - possibly an old alarm clock? You will also want an remote override facility, too, and you could probably rig one of these up from an old telly and its remote control.

It must be great being an electronics engineer, you wouldn't ever have to buy anything, you can just fix it

 

[Alfie]

An update for anyone interested; I pulled the Comand out of the car and found the giro is made by Matsu****a and has part number EWTS4F. After much trawling around on the Internet, no luck with finding a replacement or even a spec. for this component, so I reassembled the Comand and refitted it back in the car. To my surprise it then worked fine and has continued to do so for several weeks. However, last night, in the cold weather, it played up again for the first 3 or 4 minutes after switch on until it had warmed up a bit. (Still better than the 45 minutes it was taking before). Same thing as the original fault, you drive away, the cursor position on the screen updates as the car moves, but the cursor heads off in all sorts of random directions off road although the general area on the map is correct. I still suspect the giro is the culprit, but I can't find a replacement.

How many satellites does it see when this is happening?

 

[Mad Mike]

Hello Alfie,

Typcially between 5 and 8 satelites. The problem is getting worse again. Was about 15 minutes this morning before I was firmly fixed on the road and going in the right direction on the map! Definitely temperature related. Later on with the car in the sun, interior warm, it worked fine from switch on.

Just as an aside Alfie, I see you have helped a lot of people on this forum in the past. I just want to thank you for the help you've given them and for looking into this problem for me.

Kind regards, Mike

 

[mercmanuk]

ive had the same problem with the command when the direction arrow points the wrong way,its corrected itself though

 

[richard]

Hi

PM me, I have a spare giro from a COMAND (with the correct cable & connector as a result)

I dismantled a SL unit for spares for another (needed the display)

Cheers
Richard

 

[Mad Mike]

Well, I've been a while getting back here with a final conclusion to this one. Thanks to Richard, who supplied me with a replacement giro, my sat nav is working again (hot or cold!) Thanks also to those who helped along the way.

(Richard, I tried to PM you to say thanks, but your message limit is exceeded)

 

[richard]

Excellent. I've fixed my full inbox as-well !

R

 

[skymastor]

Hi all,

It's been a while since any action on this thread, but I thought I would bring this to life again because I have a similar fault and I'm after some very good advice. I retrofitted my command unit in Feb this year that came out of a 2004 CLK into my yr 2000 W203. The unit has been coded into the vehicle by MB and has been working fine ever since. It also has the MB star logo on startup, so I assume all the updated software has been installed.

My problem started last week in the cold weather when I noticed the satellites received stating none, but the position on the map seemed fine whilst driving. However, driving to Luton airport Monday morning, the position on the map was all to **** with no satellites received again! On the trip back (been driving for about 30mins) the satellites received went up to 3 but the positioning on the map was still way off! I took out my disk, cleaned it and put it back in. All then seemed to be working fine with around 7 satellites being received! The location on the map was also spot on! Bazaar!!

The rest of this week I have been driving 8 miles into work and the same distance back and the problem is back again with no satellites received and the position is showing approx 5 miles from my actual location on the map, and also moving in any direction on the display! Only today whilst the weather is a little warmer has the satellites recieved actually gone up to 2, but the positioning is still to ****!

I am wondering if I have the same problem that Mad Mike had experienced? If so, would anyone know where I could get a replacement giro like Richard had supplied to Mad Mike? Also any other additional info on this would be great.

Guy's, you help, advice and time with this is very much appreciated.

Thank you

 

[Alfie]

This could be a gyro or antennae issue. I am surprised by the varying low number of satellites received.

The comand unit will continue to operate without any satellites provided the gyro is good and you are not in an area too densley populated by roads. If the unit does lose position, which is what you are seeing, then it takes at least three satellites, commonly four to get the correct fix again.

So I would start by replacing the antennae (or making sure it can see up into the sky) as this does not involve dismantling the comand unit. From what you have explained, I think either the antennae is faulty or the circuitry to which it connects is faulty or possibly the gyro. All these components can be replaced.

 

[HughJarse]

My guess is your retrofitted GPS antennae has slipped from where you positioned it. It is now either sideways or partilly obscured from reading satellites.

 

[skymastor]

Thanx Alfie and HughJarse,

The antenna is still positioned where it always has been, on the parcel shelf and its been working great up to now. I've even took it out the car to the outside and still no satellites! I got the antenna on ebay so maybe it has malfunctioned? I will get a new one to see if it has. In addition to this, how would I know if the gyro is faulty and where would I get a new one from and at what cost?

Thanx fella's..

 

[Alfie]

Thanx Alfie and HughJarse,

The antenna is still positioned where it always has been, on the parcel shelf and its been working great up to now. I've even took it out the car to the outside and still no satellites! I got the antenna on ebay so maybe it has malfunctioned? I will get a new one to see if it has. In addition to this, how would I know if the gyro is faulty and where would I get a new one from and at what cost?

Thanx fella's..

Oay, there are sadly a lot of dodgy antenna's on ebay. I think because the map position moves with the car movement that your gyro should be fine. If not, I can supply you with one very cheaply Try a new antenna first. Remember to leave the the unit alone for a while, switched on after you swap the antenna over so it can collect satellites. Should take about 15 minutes tops. I think once you can regularly see four or more satellites, it should be fine. If not, come back to us.

 

[skymastor]

Alfie,

VMT.. I will buy a new antenna and follow your advice. it is very much appreciated. If however the problem is still there, then I will be your way for the kind offer of a gyro. But like you have stated, it does move the position on the map with the movement of the car (although in the wrong location and wrong direction!), so maybe this is in good health? Lets see.

Would like to wish you all a Merry Christmas and a Happy New Year in advance.

Kind regards.

Andy M..

 

[skymastor]

Just a last question,

Apart from ebay, where else could I buy a good priced antenna from that is better quality?

Cheers..

 

[Chas]

http://www.t-era.co.uk/Pub/default.aspx?Page=ItemListEN&CatID=TE_5