GM Service Manual Online
For 1990-2009 cars only

Scan Tool Data Definitions for Isuzu Isuzu MD F-Series 2004

Ignition 1 Signal: The scan tool displays the current voltage at the battery.

GEN L--Terminal Signal Command: The scan tool displays OK/No Voltage. The scan tool displays OK until malfunction is detected on the generator L terminal circuit, then it displays No Output.