Diagnosis & Repair

WARNING: This page is about a different car, the 2003 Toyota Prius. 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.

For diagnosis and repair procedure, see Fig 1. To check resistance of heated oxygen sensor (B1, S1), see Fig 2. To check resistance of heated oxygen sensor (B1, S2), see Fig 3.

For HO2S circuit wiring diagram, 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: DTCs P0135 & P0141 Diagnostic Procedure

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Fig 2: Testing Heater On Heated Oxygen Sensor (B1, S1)

Fig 3: Locating Connector & Testing Heater On Heated Oxygen Sensor (B1, S2)