For 456's in Europe that didn't get OBD, the error codes that get listed by SD2/Leonardo are a bit hard to decipher. eg 27 N.D. 70 Stroke Sensor (very useful at my age) Would anyone have a list - with some sort of meaning attached.
The WSM shows a list of codes from 11 through 79 on pages 346-351. If you do not have the GT/GTA WSM, let us know and we can get you a copy or I can post the pages here.
I have a GT WSM, but it hardly mentions the GTA and better yet it doesn't have much on codes G44 (p348 of the pdf) being the only page I see. So yes if possible to get a better copy of the WSM would be good.
