99 Rx300 Cel P0125 And P1155

[scottemill]

couple days ago my CEL illuminated and the VSC is intermittent as we know is an issue with this year of Lexus. I got the codes from a dealership and they came back P0125 and P1155 and recommended to replace the front two sensors. I have tried the gas cap, fill the tank, check hoses but I am reluctant to replace two sensors at once as it seems to be a chain reaction.

Any thoughts? Which of the two sensors would you replace first to see if that helps?

Thanks all

[joe913]

couple days ago my CEL illuminated and the VSC is intermittent as we know is an issue with this year of Lexus. I got the codes from a dealership and they came back P0125 and P1155 and recommended to replace the front two sensors. I have tried the gas cap, fill the tank, check hoses but I am reluctant to replace two sensors at once as it seems to be a chain reaction.

Any thoughts? Which of the two sensors would you replace first to see if that helps?

Thanks all

P0125 Insufficient Coolant Temperature For Closed Loop Fuel Control

P1155 Air/Fuel Ratio Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)

Attached is a document that will explain how to test many of the sensors. Bank 1 Sensor 1 is on the back side of the engine, accessed from the underside of the car. If you start changing parts without the test, it could get pretty expensive. I hope this helps. Good luck!

SFI__SF__file.pdf