Intermittent none start

Car will not crank

1 Fault code logged P1640 - Power loss to ecu pin 1

Swoppped main relay, and gear lock out relay

Fault can occur once or several times a day no repeat pattern

Checked ecu connections, fuse box connections

Very hard with being so intermittent

When fault occured AA can bridge starter relay and it will start stright away

Does anybody have a wiring diagram or is there any known issues with this car

Many Thanks

Chris