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HOMESERVICE MANUALSMAZDA20086 S SPORT, 4D HATCHBACK, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 688 (ON-BOARD DIAGNOSTIC (ENGINE CONTROL SYSTEM L3) (3 OF 5))DTC P0420NOTES
2008 Mazda 6 s Sport, 4D Hatchback, Standard

DTC P0420: Notes

2008 Mazda 6 s Sport, 4D Hatchback, StandardSECTION Notes
WARNING: This page is about a different car, the 2007 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.
DTC P0420 DETECTION CONDITION AND POSSIBLE CAUSES

DTC P0420 Catalyst system efficiency below threshold
DETECTION CONDITION 
  • The PCM compares the number of front HO2S and rear HO2S inversions for a predetermined time. The PCM monitors the rear HO2S inversion counts when the following conditions are met: The PCM detects inversion ratio. If the inversion ratio is below threshold, the PCM determine that catalyst system has deteriorated.
    • The front HO2S inversion counts is as prescribed when the following monitoring conditions are met:
    • The accumulated occurrence time of the following monitoring conditions has exceeded the prescribed time limit:

MONITORING CONDITION 
  • Engine speed 1, 300-3, 000 RPM 
  • Calculated TWC temperature is above 400 °C {752 °F} 
  • Calculated load 15-48%  (at engine speed 2, 000 RPM) 

Diagnostic support note 
  • This is an intermittent monitor. (Catalyst)
  • MIL illuminates if PCM detects above malfunction condition in two consecutive drive cycles or in one drive cycle while DTC for the same malfunction has been stored in PCM.
  • PENDING CODE is available if PCM detects the above malfunction condition during first drive cycle.
  • FREEZE FRAME DATA is available.
  • DTC is stored in the PCM memory.
  • DIAGNOSTIC MONITORING TEST RESULTS is available.
POSSIBLE CAUSE 
  • TWC deterioration or malfunction
  • Exhaust gas leakage
  • Looseness of front HO2S
  • Looseness of rear HO2S
  • PCM malfunction
RENDER: 1.0x

NO RELATED

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