Indication Method of Trouble Code

Turn on the starter switch, while the engine does not start.
Short-circuit terminal 8 of the self-diagnostic connector to GND (terminal 4 or 5) to display the trouble code on the CHECK lamp.

Fig 1: Identifying Diagnostic Trouble Code Connector & Terminals
Courtesy of ISUZU MOTOR CO.
If no trouble codes exist, code "12" is displayed continuously.
If trouble codes exist, code "12" is displayed three times, and the trouble codes, starting from the smaller code number, are displayed three times respectively.

Fig 2: Diagnostic Trouble Code Reading & Display Chart
Courtesy of ISUZU MOTOR CO.