there's an often reference post here DIY Diagnostic tool for injection Vespa's with MIU ECU but it doesn't work with newer Vespas. The cable plugs have changed and that software (guzzidiag) doesn't support the newer ECU.
Here's what you need for new bikes:
1. HPE GTS Vespas use a 'Euro5' plug EVEN WHEN THE BIKE IS NOT EURO5. ie, my 2019 supertech (AsiaPacific vesion) which says euro3 in the manual has the euro5 plug. This plug is red and under the pet carrier on the left, you have to squeeze to remove the black cap. Search for euro5 obd2 cable in ebay or amazon, should be less than $20. eg https://www.ebay.com.au/itm/Euro5-OBD2-6-Pin-Plug-Adaptor-Cable-Motorcycle-Moto-Guzzi-Piaggio-Vespa/133389029826?hash=item1f0e9b11c2:g:suMAAOSwDRNemYeT&frcectupt=true
2. Using you phone instead of a laptop is way easier. So we use an ELM327 bluetooth adapter to connect to the cable above. Also cheap, search for ELM327 obd2 in ebay/amazon, also less than $20. eg https://www.ebay.com.au/itm/HH-OBD-ELM327-Bluetooth-OBD2-OBDII-Check-Engine-Car-Auto-Diagnostic-Scanner/154385802098?hash=item23f21c6372:g:5lsAAOSww~pgWdGL
3. The software: I use CarDoctor on Android, there will no doubt be similar for iPhones. https://play.google.com/store/apps/details?id=com.funray.car.status&hl=en_AU&gl=US
4. The codes. It seems some codes are standard across all bikes and some are not. I think the low numbers are the standard ones (maybe less than 1000?). The number displayed will be correct but the english description will be wrong for the non standard codes. I found this list that seems to be correct for vespas (note piaggio also makes aprilla bikes) https://www.apriliaforum.com/forums/showthread.php?350345-RSV4-TuonoV4-error-codes-listing
For recent vespas (probably including primevara etc) this should all work, not just HPE (and maybe beverlys etc).
For older vespas the cable in part 1 is different, see the topic I mentioned at the start of the post for that cable (iirc that post calls it a fiat connector)
Last edited by steelbytes on Thu Apr 08, 2021 4:26 pm; edited 2 times in total