2001 Toyota Sienna Van – Heated Oxygen Sensors P1155 Code

Reader Question: Austin,

I am retired and must do my own repair work. My 2001 Toyota Sienna Van (3.0 Liter, 4 Speed AT) has 94,000 miles and showing a DTC Code of P1155 (O2 sensor heating element).

This is a great car in very good shape and I plan to keep it until the wheels fall off. Probably all of the O2 sensors are near end of their life cycle. I do not want to replace one and have another go out soon after. My questions are:

1. How many O2 sensors does this van have? (I have been told 4.)
2. Is this a job I should attempt myself? I do have the necessary tools.
3. Can you send me any information where these sensors are and/or point me to any printed materials that I can download, etc., which would help me change out these sensors myself?



Hey Bill,

That code should be for the BANK 2, sensor 1 oxygen sensor code if I am not mistaken. Therefore, the sensor should be BEFORE the catalytic converter and on the exhaust manifold for cylinders 2, 4, 6 NOT for cylinder # 1.

I assume there are four sensors, but I am just guessing not actually looking at a manual. You can replace all of them, or try to replace just the one with the problem; some of these sensors can be expensive.

As far as difficulty level, they do not usually place these sensors in easy to reach places, especially on this van. You can do it. It is not a rocket science. However, it might knock the skin off your knuckles. It also might be easier to do from the bottom and with the use of a vehicle lift or hoist.

I did a quick search for printable documents of their location but did not find anything. I am sorry.

Austin Davis

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