There is nothing in the workshop manual, so go to old school check charge at battery- make sure battery is fully charged, check at terminals at idle no lower than 12.8 volts, no higher than 13.6ish, shouldn't go much higher than those figures at revs. Should be faily constant, as well- if it fluctuates a lot, could be problems. Check that the connector for reg/ rec is clean and tight. Check earth points.
