QuestionHi Ted,
I have a great appreciation for your knowledge and experience. I follow the knowledge base that is created on this web site and I find it very resourceful.
My Toyota Avalon XLS, 1997 has Check Engine Light, scan tool shows P0135 ( Bank1 Sensor1 Heater Circuit Malfunction, Oxygen Sensor). Engine is 1MZ-FE V6. I have seen the past postings and they were very useful for my technical understanding so far and my questions are more specific to the Engine Model and specific code.
My two questions are
a) where is this located ?. Does this model have 2 sensors in Bank1 or just One. I was able to see one in the front, on the exhaust pipe , near to the radiator. is this the B1S1 OR is there a sencond one too?.
I did some study on this and understand that each of these OBDII HO2S sensors, unlike the earlier ones, have a heater to heat up the sensor to quickly make the engine switch from Open Loop to closed loop operation for exhaust efficiency, i.e with in 35 seconds.
Car is running fine, I do not see any difference in the run.
that makes me understand that O2 sensor is working fine and sending the right signals to ECU.
b) How immediatly should I go for fixng this ?. I do about 1200 miles a month. would there be any consequential problems like damage to exhaust system / engine, if I do not get this fixed immedialty?
Thanks for your time.
AnswerSivaram,
Good job on your knowledge of the O2 system. Your Avalon should have 3. Bank 1 should be the front O2 in the front exhaust manifold. Yes, it will work without the heater, but it takes a little longer to warm up. You can check the heating element inside the O2 sensor using an ohm meter if you want to confirm that is the bad O2. Unplug it and measure across the 2 white wires. You should get a very low resistance under 10 ohms. If it is open you got the bad O2 sensor. They have come down in price so I would recomend to replace it.
