2001 Lexus LS 430FACTORY OEM SERVICE PROCEDURE

ECM Power Source Circuit (Ignition Keyed): LS430

  1. Access ECM in left front of engine compartment. Turn ignition on. Backprobing connector, connect DVOM negative lead to terminal No. 7 (Brown wire) at ECM E6 connector and positive lead to terminal No. 6 (Black/White wire) at ECM E3 connector. See Fig 1. If 9-14 volts is present, ECM power circuit is okay. Diagnose by symptom. See TROUBLE SHOOTING - NO CODES article. If 9-14 volts is not present, go to next step.
  2. Check for an open circuit in Brown wire between ground and terminal No. 7 at ECM E6 connector. See WIRING DIAGRAMS article. Repair as necessary. If wiring is okay, go to next step.
  3. Measure voltage between chassis ground and terminal No. 17 (Black/Orange wire) at ECM E3 connector. If 9-14 volts is present, go to step  5. If 9-14 volts is not present, check IGN fuse in instrument panel junction box under left side of instrument panel.
  4. If fuse is blown, repair cause of blown fuse. If fuse is okay, check ignition switch. See STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT. Replace ignition switch as necessary and retest. If ignition switch is okay, repair open circuit between battery and ignition switch, or between ignition switch and ECM.
  5. Turn ignition on. Measure voltage between chassis ground and terminal No. 13 (Pink/Black wire) at ECM E3 connector. If 9-14 volts is not present, replace ECM. If 9-14 volts is present, check EFI No. 1 fuse located in engine compartment fuse/relay box at left front of engine compartment. If fuse is okay, go to next step. If fuse is blown, repair cause of blown fuse.
  6. Check EFI main relay located in engine compartment fuse/relay box at left front of engine compartment. See RELAYS  under MOTORS, RELAYS & SOLENOIDS. If EFI main relay is okay, check circuit between chassis ground and terminal No. 13 at ECM E3 connector. See WIRING DIAGRAMS article. Repair as necessary. If circuit is okay, repair circuit between battery and EFI No. 1 fuse.
Fig 1: Identifying Engine Control Module (ECM) Connectors & Terminals (LS430)
G00024256Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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