Satnav works but in the wrong place?

[PeteJG]

My satnav works, i.e. it tracks my journeys, but thinks I am about 90 miles south of where I actually am? Basically I am in Oxfordshire but it thinks I am in the New Forest!! I know the Volvo satnav is not the best around but I just want it to work! Any clues please? Can it be realigned or reset somehow?

[gmonag]

Is the data disk up to date?

[PeteJG]

No idea, but an out-of-date disk would just be unaware of road changes etc, it shouldn't have this effect surely?

[Moose Test]

It sounds as if the GPS might not have lock, so the position is being approximated by inertial guidance (gyro/accelerometer module, which is what keeps the position updated during loss of satellite signal, such as when you're driving through tunnels, surrounded by tall buildings etc.). The problem being that inertial systems have inherent error, which accumulates over time and need to be 'reset' with a good positional update from the GPS.

I'd suggest disconnecting your battery for 10 mins or so, in an attempt to make the system reset itself and try to regain GPS lock.

It's possible that there's a problem with the GPS module itself, and/or connections to its antenna, preventing it from receiving a valid signal. VIDA diagnostics would probably help in that regard.

EDIT: Just took a look at mine and whilst options/displays may vary according to the software version installed, if I select Current Position from the main menu, the screen displayed shows the text "GPS" followed by a number (7 in my case), which I believe might be a count of the satellites it current has signals from. Worth checking, if you have that option.

[PeteJG]

Thank you Moose Test. That could explain what I just found - going to the GPS info page on it I found that it doesn't seem to be getting any satellite info, and yet was tracking my progress! I guess the next place to look would be the antenna then?

[Moose Test]

The GPS module has its antenna integrated on the same board and is located underneath the plastic cover in the top centre of the windscreen (where the rain sensor also lives). From there, its shielded cable runs in the roof lining, down underneath either the left or right A-pillar cover (can't remember which but likely the passenger side) and "somehow" to the MMM under the passenger seat.

So, you can get to it but you need to be prepared to remove some trim panels. For that reason, I'd be inclined to try removing the battery connection for 10-15 mins, and trying to force a reset first.

It's also possible that the GPS module itself has failed, so if the connections are sound and a power-off reset doesn't help, I think your best bet would be either a poke-and-hope replacement with a second hand part (~20-30GBP it seems but get the same part number as your own if possible) or to get the diagnostic codes read by a Volvo code reader (i.e. VIDA/DICE).

[PeteJG]

Just got home and decided to have a go at getting to the GPS antenna, at least to see which of the various types it is. Turns out it's the one with both the copper-clad PCB and also what looks like the processor module too, so 2 cables coming out but on the drivers side and they look to disappear off towards the drivers side, although there are quite a number of cables going across the head liner between the rear view mirror and antenna so they might double back to join them, I can't see though and I'm not yet at the point of ripping the whole head liner down to find out!
I found 2nd hand antennas on ebay etc. which look compatible, but none of them look to have enough cable to reach the drive unit under the seat in one go, so are there cable joiners or maybe a box under the dash that they plug into?
As for the drive unit itself, I found one of the fibre-optic cables had pulled out of the black connector but cleaning and refitting it didn't fix anything. Why has it got fibre optic cables going to or from it at all though?

[Harley Dave]

Audio?

Cheers

Dave

[SwissXC90]

Before you start with anything physical, put the nav system into diagnostic mode and read the error codes.

From a cold boot, ENTER - BACK - ENTER - BACK continuously until a boot screen appears. You'll be in diagnostic mode. Read the faults.