P0141/P0147/P0161/P0167 O2 Sensor Heater Circuit Malfunction

Make sure the iO2SS is properly powered. Measure the unit's power input (red wire) when the engine is on; you should measure >12V.
Ensure the iO2SS's signal outputs (green wires) are connected to the appropriate oxygen sensor signal wires leading to the PCM.
Verify all other wiring and check all solder joints or crimp connectors for loose connections, frayed wires, or corrosion.
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