Code P1133

[Plato]

Hi everyone. My 1999 ES300 has just started throwing a CEL, and the OBD-II scanner reads: "P1133 Manufacturer controlled air/fuel mixture sensor". Unfortunately, it does not say which one. But, I scanned the posts and found that P1133 is Air/Fuel ratio Sensor Circuit Response Malfunction Bank 1, Sensor 1.

Apparently, Sensor 1 is an upstream sensor, in the exhaust manifold before the cat. But, is Bank 1 the firewall side or the radiator side? Is this a DYI (from the top or from the bottom), just unplugging and replacing the sensor?

Thanks for your help.

[Toysrme]

Firewall.

[Plato]

Firewall.

Thank you. I assume this is something I can reach and change myself. It seems odd that I have only 71K on the car and this happened.

[steviej]

Thank you. I assume this is something I can reach and change myself. It seems odd that I have only 71K on the car and this happened.

not odd at all. My B1S1 went at 39,000 and my B2S1 went at ~60,000.

B1S1 is the hardest to reach but do-able and best done when engine is cold of course.

steviej

[Plato]

Thank you. I assume this is something I can reach and change myself. It seems odd that I have only 71K on the car and this happened.

not odd at all. My B1S1 went at 39,000 and my B2S1 went at ~60,000.

B1S1 is the hardest to reach but do-able and best done when engine is cold of course.

steviej

Thank you, Steviej, I was worried that I had overlooked some proper maintenance. I'm reading that the part is a bit pricey, but that the Toyota part should fit and be somewhat less. Plato