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Home >> Toyota >> 2004 >> Matrix Base, FWD, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 133 (Engine Control System Self Diagnostics) >> Diagnostic Tests >> DTC P0420: Catalyst System Efficiency Below Threshold (Bank 1) Or P0430: Catalyst System Efficiency Below Threshold (Bank 2) >> Diagnosis & Repair
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Diagnosis & Repair

WARNING: This page is about a different car, the 2003 Toyota Sequoia. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: 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 a deteriorated TWC, perform Confirmation Engine Racing Pattern Procedure first. See CONFIRMATION ENGINE RACING PATTERN .

For diagnosis and repair procedure, see Fig 1.

For ECM location, see Figure. For ECM connector view, see Figure. For testing of systems or components, see SYSTEM & COMPONENT TESTING - V6 & V8 article. For removal and installation of components, see REMOVAL & INSTALLATION - V6 & V8 article.

Fig 1: DTCs P0420 & P0430 Diagnostic Procedure (Steps 1-4)
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