The check engine light on my 98 ES300 is on. I had the code read out and it is P0135 "O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1). Can anyone explain what this code means and what I have to do to correct it. I replaced the bank 1 O2 sensor and had the code reset but it just came back.

Thanks, John M

 

Bank 1 sensor 1 is the sensor closed to the firewall. Which sensor did you replaced? You can use the " Search " function and type in O2 sensor and you will find a lot of good info about this topic.

 

P0135 - Trouble areas are -

Open or short in heater circuit or heated oxygen sensor
Heated Oxygen sensor heater
ECM

is what the manual says.

Jonny