Member Since: 05 Aug 2019
Location: Kent
Posts: 30
Sat nav
Having problems with my 2012 sat nav. The word gps has a red line through it. I know there is a secret menu to check things like satellites etc. I managed to access it earlier but now I can’t find it.
Enclosed is a pic of one page before I lost it. Anyone know what this means and also how to get into it again?
Thanks
Richard
13th Jul 2021 7:26 pm
Hobson
Member Since: 20 Jun 2018
Location: Essex
Posts: 164
You can get to the satnav diagnosis menu by going to "Dest. Entry", then touch and hold between the two letter T's in the word "Destination" for about 6 seconds. This will bring up the screen you want. The GPS information option will give you two screens; one showing your current location and number of satellites and the other the details of the satellites and other info e.g. HDOP.
Click image to enlarge
Click image to enlarge
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Click image to enlarge
The red line through GPS indicates that the GPS signal isn't being received by the nav unit. I had exactly this problem. It turned out to be a poor connection on the head unit. Disconnected all the plugs, plugged them back in and it's been perfect ever since. Worth a try before you start chucking parts at it. Can't be certain but I think it was the fibre optic (MOST) connector that was the problem. Lots of fun getting the nav unit out though!!!!
13th Jul 2021 10:05 pm
Rands100
Member Since: 05 Aug 2019
Location: Kent
Posts: 30
That’s great, thank you. I’ll try it when I get in from work this afternoon.
14th Jul 2021 3:23 am
Rands100
Member Since: 05 Aug 2019
Location: Kent
Posts: 30
Well I don’t seem to pick up any satellites.
I notice HDOP is way different to yours. What does it mean?
I guess it’s out with the unit
14th Jul 2021 2:17 pm
Rands100
Member Since: 05 Aug 2019
Location: Kent
Posts: 30
14th Jul 2021 2:19 pm
Hobson
Member Since: 20 Jun 2018
Location: Essex
Posts: 164
You have no GPS signal reaching the nav unit. HDOP = Horizontal Dilution Of Precision. Put simply it's a measure of how accurate your GPS will be. The lower the number the better the precision. With the full 8 satellites located it will be about 1.
I think you need to start belling out the circuit to eliminate the GPS antenna and wiring as the cause of your signal loss. Then have a look at the connections on the unit itself. It could be a failure in the nav unit itself if you're unlucky, but look for the simple stuff first.
There is a connector under the roof panel trim in the boot and a further one under the gear selector in the floor console. You will be in world of hurt if it turns out to be the GPS antenna, horrible job!!!!
Have you any means of reading DTCs? I'd put money on you getting the one (can't recall actual DTC number) that relates to the GPS antenna circuit being open circuit.
14th Jul 2021 3:53 pm
Rands100
Member Since: 05 Aug 2019
Location: Kent
Posts: 30
This is what I’m getting with my gap tool.
And this is the back of the unit, I was expecting to see a blue socket (fakra?) from the antenna.
The connector under the rear tailgate trim seems okay.
Where does the antenna cable go to? Is it under the passenger seat? Although I thought it went direct into the unit
14th Jul 2021 4:47 pm
Hobson
Member Since: 20 Jun 2018
Location: Essex
Posts: 164
It does go directly to the Integrated Audio Module (IAM). it runs up the centre of the car and there is an intermediate connector in the floor console underneath and to the left of the gear selector. The IAM is then connected to the touch screen. I suspect that in my case the connection to the screen was not good.
14th Jul 2021 5:29 pm
Rands100
Member Since: 05 Aug 2019
Location: Kent
Posts: 30
If I put a multimeter on the cable under the roof trim at the rear would I expect to see a voltage there?
14th Jul 2021 5:45 pm
Hobson
Member Since: 20 Jun 2018
Location: Essex
Posts: 164
No, I don't think so. The antenna isn't powered. Have you tried reconnecting everything and seeing if it makes a difference?
14th Jul 2021 6:06 pm
Rands100
Member Since: 05 Aug 2019
Location: Kent
Posts: 30
Yes, it’s all back together and just the same. Might take it all out again to see if I can find the connector on the other unit
14th Jul 2021 6:19 pm
Hobson
Member Since: 20 Jun 2018
Location: Essex
Posts: 164
I've just realised that your photo is of the touch screen not the IAM. The IAM sits below the touch screen and that's where the GPS antenna plugs in. I'm just off out for an hour or two dog training but I'll dig out the wiring diagram for you when I get back.
14th Jul 2021 6:23 pm
Rands100
Member Since: 05 Aug 2019
Location: Kent
Posts: 30
That will be good, thank you
14th Jul 2021 6:36 pm
Hobson
Member Since: 20 Jun 2018
Location: Essex
Posts: 164
Have a look at these. Should be clear enough to see what's what.
14th Jul 2021 9:12 pm
Rands100
Member Since: 05 Aug 2019
Location: Kent
Posts: 30
Well, I took the dash and centre console out again and plugged in a cheapo gps antenna direct into the unit and it worked okay. So that ruled out the unit.
Next to check was the cable to the antenna and the antenna itself. I disconnected it under the trim on the tailgate and measured the impedance, should be about 50 ohms, which it was.
Next to check was the cable to the unit. Found the centre pin was broken!
I cut the plug off and also cut in half a male to male adaptor and soldered them together.
Plugged it back in and sat nav now works fine.
Thank you very much for your help.
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