I have a code that says the oxygen sensor is bad , but i replaced both the front and rear sensor and still have the same problem what else should i look for
oxygen sensor on 2003 Toyota Sienna
First of all, what is the code number? The code doesnt usually say the oxygen sensor is bad, but it will specify, bank one or bank two, up stream or down stream, and if it is a heater circuit code, lean code, rich code, ect....... you could have something as simple as a vacumm leak or possibly a cracked exhaust manifold. But start with the code number and let me know.
code is P0135 oxygen heater circut malfunction
The majority of the time that code does indicate that the heater in the o2 is faulty, and an 02 replacement is required. But, there are power circuits and wiring checks to be done to assure that the component is faulty. Find a reliable shop and have the O2 circuits tested to confirm it is the O2 sensor.