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Diagnosis & Repair

WARNING: This page is about a different car, the 2002 Toyota Sequoia. However, it is still accessible from the selected car via links, so may be relevant.
  1. Remove glove box and heater duct (if necessary) for access to ECM with electrical connectors still installed on ECM. See Figure. Using voltmeter, check voltage between body ground and terminal No. 1 (Black/Yellow wire) at ECM electrical connector E4. See Figure. This is the BATT terminal on ECM. Voltage should be 9-14 volts. If voltage is not within specification, go to next step. If voltage is within specification, replace ECM.
  2. Remove EFI No. 1 fuse (20-amp) from fuse/relay box at driver's side front corner of engine compartment. Inspect EFI No. 1 fuse. If EFI No. 1 fuse is okay, reinstall fuse. Check wiring harness and electrical connectors between EFI No. 1 fuse and ECM. See WIRING DIAGRAMS article. It may be necessary to check wiring between battery and EFI No. 1 fuse. For additional wiring for EFI No. 1 fuse to the battery, see POWER DISTRIBUTION article in WIRING DIAGRAMS. If EFI No. 1 fuse is defective, replace fuse and check for short in wiring harness and components connected to EFI No. 1 fuse. See WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.
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