The 4HL1 ECU typically features multiple high-density connectors. While exact pin positions can vary slightly by model year (e.g., 4HL1-1 vs. 4HL1-2), the Isuzu 4HL1 Workshop Manual identifies several key terminal groupings:
He moved to the ground pins. He switched the multimeter to continuity mode. He probed the ground pins on the ECU connector. isuzu 4hl1 ecu pinout