Cyrus951

Sometimes the GPS works, other times the GPS positioning is off by 20-50 miles (as seen in the photo).

What could be causing this? Bad navigation antenna?

The problem's timing seems to coincide with a radar detector and dash cam install that has power tapped from the driver side interior fusebox, wondering if there could be some sort of interference?

chsu74

I get this issue when coming out of my office parking lot. The satellite count is zero and up to 4 after awhile. Typically during cloudy days when reception is limited.

Much of this issue points at a loose GPS antenna wire from PCM when I googled. I am gonna track down the connections when weather gets warmer..

wkearney99

Seems like that would be easy enough to confirm, disconnect the power to the added items and see if the GPS situation changes.

You have a location where it's known to be wrong, see if it's repeatable there. Repeat that it fails with the gear connected. Disconnect the gear and drive back through the same area. I'd think you'd want to totally power off the PCM between the tests, so make sure that it has the chance to re-acquired the GPS satellites each time. If disconnecting the gear doesn't improve the situation the likely problem is the GPS receiver board in the overhead console area.

ToreB

My GPS is off by several kilometers, but works normally. It has been like this for many days, and it is not a coverage issue.
Did you resolve this problem?
Cheers,
Tore

ToreB

I found my problem, my Blackvue DR590 dash cam mounted aside the windscreen console containing the GPS antenna.
Removed the camera and all is well.
Cheers,
Tore

Picasso gato

I have a PCM 2.1 in my 2006 997 first série. My GPS stopped working. On Status shows 0 satellites. Is the GPS antenna inside the Navigation box, or somewhere else outside ? Thanks for any help ,

wkearney99

I wonder how this is going to affect things...

https://www.greatharbourtrawlers.com/military-jamming-gps.html

wkearney99

It helps if you add a location to your profile here. That will help other members frame their answers. Because if you're in a flat or dry place then issues like nearby mountains, heavy tree cover or weather would be unlikely to be factors.

Anything that uses GPS depends upon being able to hear radio signals from multiple satellites. It's a faint signal and most units need to be able to hear at least 4 in order to calculate your location. Your location isn't known by the satellites, it's your PCM hearing the signals, knowing where they are in the sky (a database of these is built-in), and doing a very quick calculation to triangulate your location. The signals can get blocked by heavy tree coverage (lots of leaves), heavy rain/snow (same issue, it's the water content), or physical blockages like being in a mountainous valley, among lots of tall concrete buildings, in parking garages or going through tunnels. Most automotive systems that use GPS will augment it by using 'dead reckoning' and the vehicle's own map data. As in, the speed, odometer and wheel angle. So you can lose the signal for a short time and the system won't immediately freak out.