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Home >> Kia >> 2021 >> Niro LX >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System Diagnosis (HEV) (3 Of 6) >> DTC P0420-00: Catalyst System Efficiency Below Threshold (Bank 1) >> System Inspection >> O2 Sensor Inspection
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O2 Sensor Inspection

Inspection Condition (+) Probe (-) Probe Reference
Connector Terminal connector Terminal
1. Engine "ON". HO2S (bank1, sensor2) connector 1 (signal) HO2S (bank1, sensor2) connector 2 (ground) Figure below
Good → Go to "Verification Of Repair " procedure
No Good → Carefully re-do this troubleshooting guide steps.
→ If no problems were found with circuits or connectors, replace the HO2S (bank1, sensor2) and go to "Verification Of Repair  r" procedure.