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 will set if, with engine warmed up and idling, response time for heated oxygen sensor output voltage to change from rich to lean, or lean to rich, is .9 second or more. (2 trip detection logic). Possible causes are:
- Open or short in heated oxygen sensor circuit.
- Defective heated oxygen sensor No. 1.
- Defective EFI relay.
- Leaking air intake system.
- Fuel pressure problem.
- Faulty fuel injector.
- Faulty ECM.