Circuit Description
WARNING: This page is about a different car, the 2003 Lexus GX 470. However, it is still accessible from the selected car via links, so may be relevant.
For circuit description, see CIRCUIT DESCRIPTION under DTC P0031, P0032, P0037, P0038, P0051, P0052, P0057 OR P0058. DTC is set when after engine is warmed up, heated oxygen sensor (bank 1, 2 sensor 1) output does not indicate RICH (0.45 volts or more) even once when engine speed is at 1400 RPM or more, vehicle speed is 25-81 MPH, and throttle valve does not fully close 180 seconds or more after starting engine for at least 65 seconds. Possible causes are:
- Open or short in heated oxygen sensor circuit.
- Defective heated oxygen sensor No. 1.
- Defective heated oxygen sensor heater No. 1.
- Leaking air intake system.
- Fuel pressure problem.
- Faulty fuel injector.
- Faulty PCV valve and hose.
- Gas leakage on exhaust system.
- Faulty ECM.