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Ecu Power Supply & Ground Tests: Legacy

  1. Check ECU Power Supply Circuit  - Turn ignition on. Verify at least 10 volts between ECU 12-pin connector terminal No. 12 (Yellow wire) and ground and between ECU 22-pin connector terminals No. 2 (Yellow/Red wire) and ground, No. 13 (Yellow/Red wire) and ground, and No. 15 (Yellow/Red wire) and ground. If at least 10 volts are present, go to next step. If at least 10 volts are not present, repair harness or connectors as necessary.
  2. Check ECU Ground Circuit  - Turn ignition off. Disconnect ECU connector. Verify zero ohms between ECU 26-pin connector terminals No. 14 (Black/White wire) and ground, No. 15 (Black wire) and ground, No. 24 (Black/Yellow wire) and ground, No. 25 (Black/Yellow wire) and ground, and between ECU 22-pin connector terminals No. 11 (Black/Red wire) and ground, and No. 22 (Black/Red wire) and ground. If zero ohms are present, see LEGACY under IGNITION CONTROL SYSTEM TESTS  . If resistance is more than zero ohms, repair harness or connectors as necessary.
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