SatNav inaccuracy (AMi III)

[LooneyTunes]

Slightly unusual one, but took the Vantage out for a run today and, for the first time in several years, used the built in Nav instead of Google maps via CarPlay.

It struggled initially to locate me (car had been driven for about an hour at that point) and then subsequently proceeded to suffer from very variable accuracy, often putting me several metres either side of the roads I was driving, in some cases thinking I was in different nearby roads (and making odd routing suggestions as a result).

Was out in the countryside so no tall buildings but sometimes hills/valleys so I did wonder if it might have been struggling to lock on to a sufficient number of satellites.

Has anyone encountered similar before and, if so, did it reoccur/prove to be easily fixable?

ETA: thread title seems to have got messed up. AMi III.

[Seakingsam]

Hi LooneyTunes, I had the same issue in my 2017 V8VS with Ami III, and it drove me nuts for months.

I had purchased the V8VS in December 2019 at 2,500 miles from AM Nottingham. The sat nav would be fine for a short time, but then exhibit the symptoms you have seen, with spurious directions to odd roads and satellite fix displaced off the current road.

My primary mission was initially to complete the full Bamford Rose upgrade in the UK and then ship home to New Zealand, which was done. As the car arrived during the pandemic, the initial trips were necessarily rather short, and the sat nav issue often didn't materialise.

However, as trips became longer, I noticed the wandering satellite lock. AM Auckland were determined to find and fix, and enlisted Gaydon for trouble-shooting, and software upgrades - all to no avail.

Gaydon started requesting detailed information on the system, with video of the problem, and suggested using various external satellite data apps to show current state of sat fixes at time of the problem (problem would start, so into app to show current state, video the presentation of the issue, show CarPlay position through Ami III and also same CarPlay on iPhone disconnected from Ami III).

Two photos below shows the issue.

The data flow showed Ami III was switching from satellite fix to DR or Dead Reckoning, as the system wasn't seeing any satellites despite the stand-alone iPhone and apps showing solid lock on up to 12 satellites.

That lead to identifying the problem and to the ultimate solution - the cable connecting the sat nav aerial the Ami III module was faulting - Gaydon finally decided it was an intermittent short from original assembly. The solution was to have AM Auckland build up a new co-ax cable with new plugs, and bypass the cable buried in the wiring loom.

Fitted and fixed - problem gone for good, never to return. Take a bow Paul Staples, National After Sales Manager, AM New Zealand - Paul's dedication to resolve the issue, and to drive Gaydon (and AM regional in Singapore) to dedicate resources to find the permanent solution, was above and beyond any reasonable expectation. All this at virtually no cost to myself. Remarkable.

So LooneyTunes, I suggest as a first step whenever the issue arises, immediately go into Ami III system settings and check out status of GPS - it will likely show no satellites in view, and on DR. Then unplug your phone and check satellite status on the disconnected phone. If all the satellites in view, with a solid fix, you have your issue, with faulty connection quality aerial to module.

That bit of insight took months of angst and multiple long trips to resolve - delighted to be able to pass on.

Edited by Seakingsam on Wednesday 24th April 21:14

[Felonious]

Interesting... I also had this intermittent issue, not just using the AMi iii native satnav but also if I was using Google Maps, Waze, Apple Maps, whatever: if my phone was plugged into CarPlay then no map had no clue where I was. Unplug it, and my phone sorted itself out and knew where it was. Baffling.

The MD tried a new aerial, new cabling from the aerial to wherever the hell the aerial cable goes but the only thing that worked was to swap out the AMi iii infotainment unit, which sits forward of the boot to the left.

The fix itself was fast, but the diagnostics was a head-scratcher.

[LooneyTunes]

Thanks guys, appreciate the responses.

I’ll run a few tests comparing with iPhone/Google maps, but great to have a couple of things to start looking at.

[Seakingsam]

I had my Infotainment module replaced upon importation into NZ (UK module to Rest of World module) - the faulting GPS lock had occurred previously in the UK each time I took the V8VS from Bamford Rose up the M6, and continued exhibiting exactly the same symptoms with the replacement infotainment module in NZ.

As Felonius says, the diagnosis was long and arduous - AM swapped the infotainment unit again at their cost, the tracker aerial was found mounted on top of the GPS aerial (?) and so the tracker, cabling and aerial were removed in their entirety, a replacement GPS aerial was mounted, new and bespoke software was prepared by Gaydon and installed by AM Auckland - none of it worked. Both native satnav and CarPlay would provide accurate satellite lock for 20-30 minutes, and then start to wander.

I got to the point of saying to the team that it was all too hard, and I hadn't bought and upgraded the V8VS for nav capability. The local AM team lead by Paul, however, wished to persevere. They had conferences with Gaydon, and Gaydon called for the detailed data flow identified previously - video, sat detail, screen shots etc. The coax cable from the module to the head unit was identified as the only element in the chain not investigated or replaced. The plugs at either end are, apparently, Bentley plugs and so that took a little while to source - then a specialist to build and install the cable ... and that was that!