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Home >> Hyundai >> 2004 >> Santa Fe Base, Standard >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System Diagnosis (2.4L) (2 Of 2) >> DTC Troubleshooting Procedures >> DTC P0421: Catalyst System Efficiency Below Threshold (Bank 1) >> Scantool Diagnostics >> Monitor Scantool Data
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Monitor Scantool Data

  1. Ignition "OFF".
  2. Connect Scantool and Engine "ON".
  3. Monitor the HO2S parameters and signal waveform on scantool.
    Fig 1: Screen Display - HO2S Signal Waveform
    G07378672
  4. Are those HO2S1 and HO2S2 within specifications?

    YES

    • Fault is intermittent caused by poor contact in the sensor's and/or PCM's connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "VERIFICATION OF VEHICLE REPAIR " procedure.

    NO

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