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Home >> Toyota >> 2004 >> Matrix XR, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 130 (Engine Control System Self Diagnostics) >> Diagnostic Tests >> DTC P0420: Catalyst System Efficiency Below Threshold >> Diagnosis & Repair
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Diagnosis & Repair

WARNING: This page is about a different car, the 2003 Toyota MR2. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: This DTC uses two-trip detection logic. Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected. To aid in diagnosis of deteriorated catalyst, it is recommended to perform Confirmation Engine Racing Pattern while observing HO2S waveform pattern. See CONFIRMATION ENGINE RACING PATTERN .

For diagnosis and repair procedure, see Fig 1. To check HO2S heater (Bank 1 or 2 Sensor 1) resistance, see Figure or Figure . To check resistance of HO2S heater (Bank 1 Sensor 2), see Figure.

For location of emission related components, see Figure.

For ECM location, see Figure. For ECM connector terminal view, see Figure.

For testing of systems or components, see SYSTEM & COMPONENT TESTING - 4-CYLINDER article. For removal and installation of components, see REMOVAL & INSTALLATION - 4-CYLINDER article.

Fig 1: DTC P0420 Diagnostic Procedure
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