EFI SYSTEM — Troubleshooting for EFI Electronic Circuit with Volt/Ohmmeter FI-33 • +B ↔ E₁ ① There is no voltage between ECU terminals +B and E₁. (IG S/W ON) ② Check that there is voltage between ECU terminal +B and body ground. (IG S/W ON) NO OK Check wiring between ECU terminal E₁ and body ground. BAD Repair or replace Check fuse and wiring harness. BAD → Repair or replace OK ↓ Check NO. 1 main relay. BAD → Replace • IG S/W ↔ E₁ ① There is no voltage between ECU terminals IG S/W and E₁. (IG S/W ON) ② Check that there is voltage between ECU terminal IG S/W and body ground. (IG S/W ON) NO OK Check wiring between ECU terminal E₁ and body ground. BAD Repair or replace ↓ Check fusible links and ignition NO → Repair or replace switch.