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2018 HONDA ACCORD
1.5L I4 Turbo•FWD•CVT•gas•turbo
6 active safety recalls on this vehicle — view recalls
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Repairs402Labor502Torque3379Fluid7DTC1924Battery1Maintenance0Recalls6
P2423moderate severityPowertrain

HC Adsorption Catalyst Efficiency Below Threshold (Bank 1)

on 2018 Honda Accord 1.5L I4 Turbo · FWD

What this code means

The hydrocarbon adsorption catalyst on bank 1 is not trapping and converting HC emissions effectively. This usually means the catalyst has degraded over time.

Symptoms

  • Check engine light on
  • Failed emissions test
  • Reduced catalyst performance

Common causes

  • Degraded or aged catalyst
  • Exhaust leak upstream of catalyst
  • Faulty oxygen sensor readings
  • Engine running rich causing damage

Diagnostic steps

  1. Scan and verify related codes
  2. Inspect exhaust system for leaks
  3. Check oxygen sensor operation
  4. Replace catalyst if efficiency low
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