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Home >> Toyota >> 2004 >> Matrix XR, FWD, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 17 (Engine Control System Self-Diagnostics) >> Diagnostic Tests >> DTC P1600: Engine Control Module Batt Circuit >> Diagnosis & Repair
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Diagnosis & Repair

WARNING: This page is about a different car, the 2002 Toyota Land Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
  1. Remove glove box 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/Red wire) at ECM electrical connector E9. 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 fuse (20-amp) from fuse/relay box at driver's side front corner of engine compartment. EFI fuse may also be referred to as ECD fuse. Inspect EFI fuse. If EFI fuse is okay, reinstall fuse. Check wiring harness and electrical connectors between EFI fuse and ECM. See WIRING DIAGRAMS article. It may be necessary to check wiring between battery and EFI fuse. For additional wiring for EFI fuse to the battery, see POWER DISTRIBUTION article in WIRING DIAGRAMS. If EFI fuse is defective, replace fuse and check for short in wiring harness and components connected to EFI fuse. See WIRING DIAGRAMS article. Repair wiring harness or electrical connectors as necessary.
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