Circuit Description

WARNING: This page is about a different car, the 2003 Lexus IS 300. 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 engine speed is 1,400 RPM or more, vehicle speed is 25-81 MPH, throttle valve does not fully close and 180 seconds or more have passed since engine was started. Heated oxygen sensor output does not indicate RICH (.45 volt or more) for at least 65 seconds. Possible causes are:

Open or short in heated oxygen sensor heater circuit.
Faulty heated oxygen sensor heater.
Faulty air induction system.
Faulty fuel pressure.
Faulty injector.
Gas leakage on exhaust system.
Faulty PCV piping.
Faulty ECM.