Chargers indicate "OK," if the alternator is outputting between 13.4 volts DC and 15.6 volts DC. A fault indication will be given for voltages outside this range.

A fault indication doesn't mean the alternator is bad; it indicates that the alternator didn't read between our pre-selected range, and you should check with the manufacturer of your vehicle for proper specifications, or consult an automotive electrician for more assistance.