Diagnostic Aids
WARNING: This page is about a different car, the 2003 Lexus RX 300. However, it is still accessible from the selected car via links, so may be relevant.
If DTC P0135 is displayed, check bank 1 sensor 1 circuit. If DTC P0155 is displayed, check bank 2 sensor 1 circuit. Bank 1 refers to the bank that includes cylinder No. 1. Bank 2 refers to the bank that includes cylinder No. 2. Sensor 1 refers to the sensor closest to the engine body. Read freeze frame data using hand-held tester or OBD-II scan tool, as freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful to determine whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich at the time of the malfunction.