Rt4 satnav no satelites

[Filberton]

I have an odd problem on my RT4 unit (on the Citroen, but I don’t think it is model dependant).

With lockdown I have not used the satnav since December but now when I access the maps it says “No Satellites visible” the height reading also stays blank ( but I believe it is not an altimeter but takes heights from the mapping.) Oddly the map still knows roughly where I am but only within about a mile and the map/cursor moves when the vehicle moves. If I go to Leeds it knows I am in the Leeds area or to York, in the York area. The compass moves with vehicle turns but often points in the wrong direction but when I stop everything stops moving.

I could understand if there was no movement ie if a broken wire or truly no satellites but for it to part work is odd?.

I have done a full BSI reset, reloaded the master software (version 8.31). Everything else works and the unit even tries to plot a route to navigate but as soon as I start, the map says I’m in a field!!

(Does anyone know where the gps module is in the car or which Fakra plug and pin the GPS comes in and I might be able to check for a data signal) - all plugs in the head unit are tight and besides which the fault is continuous not intermittent.

One guy said it is because of Brexit and access to the Eurosat but I am assured this is not true and besides that, if that were the case it would not part work.

Whilst not the best, it would be nice to use it rather than GoogleMaps!

Hoping someone can help.

Thanks

Mike

[GiveMeABreak]

Hi Mike. Hopefully this is a simple fix for you.

The mapping system obviously relies on satellite positioning - but after a period of inactivity it looses data. To fix this you need to actually go for a drive of at least 10-15 minutes and when I say a drive, that's what I mean - having the engine running is no good. It needs to relocate and calibrate itself using the satellites whilst in motion to provide an accurate location fix.

After you've been for a drive it should start to restore the number of visible satellites and prevent you ending up in the moat.

[mickthemaverick]

In addition to Marc's advice I would suggest it might be worth checking the connections at your antenna. It seems to me that it may not be receiving gps signals properly but it is working out your rough location from fm and am station sites. On the MK1 the antenna had four connectors including the GPS one and I could have the radio working without GPS but the mapping did know my local area, so it is worth a check.

[Filberton]

Thanks Marc, that makes sense.
I have done two thirty minute drives this week but will keep driving around a bit as lockdown allows travel and will see what happens. (I may have a longer 3-4 hr drive shortly).

I will also try Mick’s suggestion and see if I can check the antenna connections (accessed through the rear courtesy light hole I believe)?

I did seem to recall on the X7 the gps aerial was a separate unit (I have it in my mind it is in the rear left pillar) but I can’t see it on my data (I thought I’d seen it on my data sheets but can’t find it now ....but then, my data is a bit flakey as it is an EBay copy of the Citroen workshop discs but it has never fully loaded properly ).

I’ll also pull the head unit again as well just in case although the Fakra plugs lock in so unlikely they have come loose. I’ll check the actual wires this time.
I suspect Marc is right as it was parked up for a while and since last September it has seldom done more than 10 miles in any journey which is probably the last time I used the satnav.

Thanks guys...I appreciate the help and quick response

[Filberton]

Yippee! As a final close-out, I am pleased to say, (many thanks Marc ) my sat-nav has finally found itself. So nice to hear that voice once again, albeit I have always puzzled why when it is in English it still uses French vowel pronunciation so I once again I seem to drive on the I 246 instead of A246 or I6 instead of A6 (aye being the French pronunciation for the vowel A).

The car has stood for much longer without loosing its memory (eg at airport car parks) but on this occasion the battery was disconnected. Presumably the Magnetti unit has capacitance or something to hold a charge for a short time whilst battery is changed or repairs but will not last for weeks.

Either way all is once again working so thanks again folks.

[GiveMeABreak]

Pleased it seems to be behaving now.

[Filberton]

Can anyone tell me where the GPS module is for the satnav please on the C5x7 saloon? Is it with or within the Shark-fin aerial? …and if so, is it accessible through the headlining via the rear roof light, or where is it and how do I access it?

As on my previous posts on this, after a period of working my satnav has gone back to getting lost and the “No Satellites” signal. (Sorry Marc, I thought we’d fixed it but the gremlin is back ). Some days it works fine, other days it takes maybe 10 miles of driving before it works (sometimes with zero satellites when I think it is on 4G, sometimes it finds satellites. When it works it is fine so I start to suspect a connection and maybe the aerial? Could it be a bad connection?
I did initially put it down to a dead battery during COVID but now suspect corrosion/connection.

I have removed the head unit and cleansed connections at that end so thought I might check the other end and check for continuity…. But where is the other end? Does anybody know or have a more detailed manual which shows where please?

If the connections are ok, I might try a cheap GPS aerial as it would be nice if It would work all the time. At present I use a mobile in a cradle running Google Maps which has some advantages but also some disadvantages.

M

[GiveMeABreak]

OK so I need to correct some of your assumptions here to start with:

1) On the RT4 the GPS tuner module is contained within the Head Unit.
2) The Aerial on the roof is just the GPS aerial along with the other GSM / FM antenae
3) 4G is a wireless mobile communications cellular network - it has nothing to do with GPS.

So with that out the way, a lack of satellites is generally the aerial on the roof that has had water creeping in over the years and now started to corrode the connections. So your starter for 10 is to get a cheap ebay GPS aerial with fakra connection that you can temporarily stick on the dash and plug into the GPS aerial port, then go for a 10 minute drive. You can't just leave the vehicle stationary as it needs to be moving to lock onto the satellites.

If your satellites visible number has increased significantly, then that probably tells you the aerial need sorting. So so that first before anything else.

[Bandit12]

I had this problem a while back but only just got around to fixing it. I followed Marc's advice bought a small GPS with fakra off amazon for 8 quid, plugged it in and it works a treat. I simply stuck it to the inside top left hand corner of the windscreen and hid the wires behind the a post trim. Barely noticable. I decided not to replace the proper aerial on the roof of the car as I never found if it was an aerial or a wiring fault together lots of faff with wiring under the headlining between back and front of the car.