how long have you had this problem? sometimes it takes a while before the nav computer can recalibrate itself. if you've had this problem for over 1week, then you'll need to take additional steps to force the recalibration. if it's only been a few days... try driving around the city for a few hours. I think it helps if you make a loop so that your car has travelled in all directions at one point.

Perform a calibration run.
Gyro calibration: occurs when ign is turned off, and all doors/bonnet/boot/sunroof are closed.

Speedo calibration: requires a drive of around minimum 5min at a decent constant speed - I use the motorway for 5 min.

Check all your sensors are working - wheel pulese, direction sensor and gyro. You can observe these in the service mode (MENU - Set - then press and hold MENU until Service mode appears)

And then to help us further diagnose your problem, report your fitted software version - top RHS of Set screen.

Check also your GPS receiver status in the Service Menu and report what you find

Cheers guys thanks alot for the help. I've had this problem for as long as can remeber. It hasn't worked properly ever and I've done the updates whenever new ones were available so I feel that I've tried everything off the top of my head. My current version is the 9.1 version (V.291 I think its called) so Its up-to-date. When I got to the service menu one can see that all the diffrent pulses etc. have figures attacheds to them that are changing constantly. But the wheel sensor shows negative figures when going forward and positive when moving bakwards, is that suppose to happen? Maybe Its the wheelsensors not working properly because the gyro seem to working, one can see that it turns when turning the car. In tunnels the GPS switches to the wheelsensors and It follows the actual position quite well but its the combination of the sattellites and the sensors that delay the cursor when positioning! As told my receiver, the small black "puck", was retrofitted and is aftermarket. Should I try with a OEM one? Thanks for the help guys really appreciate it.

Wheel sensor MUST be positive going forward and negative going backwards.
Make sure the Direction of Travel shows correctly Forward or Reverse.

Your GPS antenna (black puck) won't make any difference, that is just an antenna. The GPS receiver is built in to the Mk4.

You should try the Mk4 in another vehicle and check the speed pulse input etc to confirm if the problem lies in the nav unit or in the car.

Jochen

Had an MK3 before and it did the same, then I bought an MK4 and still the same. Sorry for the mix --> GPS antenna/receiver understand now that its not the same! So back to the issue, even when changing hardware there was no change! So I think the problem lies in the fact that the wheel sensor is sensing wrong direction. Or what do you think?

either a faulty wheel sensor or the antenna would be the most likely culprets

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Anybody know what to look for if the wheel sensor's the culprit? Should I dismantle and do an autopsy or is there any other quicker remedy? When retrofitting an OEM nav what are the "stumbling blocks" one may encounter? I think that the guy who retrofitted my nav wasn't to careful when alining the sensor, as you say, that may be the villain here!

Have you done this step yet?

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