Code P0155

[Tones]

There are only 4 sensors. For each side, there is one before the cat (sensor 1) and one after the cat (sensor 2). The bank 2 sensor 1 is before the cat on the passenger side. The ones after the cat are flanged, the ones before the cat are screwed.

[bud4ya]

TY I think I have the right one then. It is on passenfer side before cat. You can only access it if you are laying under the truck.

Originally Posted by Tones

There are only 4 sensors. For each side, there is one before the cat (sensor 1) and one after the cat (sensor 2). The bank 2 sensor 1 is before the cat on the passenger side. The ones after the cat are flanged, the ones before the cat are screwed.

[Tones]

That is the one I changed on my sister's sequoia and the code has not returned.

[tjdmax]

I'm new to the forum and had some questions on the PO155 code for a 2003 highlander. I'm thinking of replacing the 02 sensor myself. I think the highlander has only two sensors, one in the engine compartment, and the second one is after cat. converter? The code is for the bank2 sensor1 which is the one after the cat. converter? The wires for this flanged sensor go up under the drivers seat. Is there any tricks or advice that could be shed on replace of this sensor. Any pictures would also be helpful too. Thanks

[HOGWILD]

which engine ya got
2AZ-FE or 3MZ-FE ?
this is for the 2AZ-FE if ya need the 3MZ-FE pdf let me know!
so did you get a code from your OBDII system? did ya get it cleared or is it still in their?
Highlander Diagnostioc codes are not same numbers as Tundras? i think the second pdf will help you but ya need to know what code was thrown or you will spend a group of money changing the wrong O2 Sensor! take it and get the code read for free at autozone and see which code ya got first!

[tjdmax]

The engine that it has is a 1MZ-FE. The is what the labels say on the underside of the hood. I went to auto zone and used there OBDII tester on it came up with the code P0155 bank 2 sensor 1. I did look again and I can find three sensors, two before the cat. converter, and one after. The PDF of the 3MZ-FE engine looks correct for the two up front. You are right the sensors are expensive and I want to replace the correct one.

[HOGWILD]

i will see if i can find something on that engine!

[tjdmax]

Hogwild, it looks like the 1MZ-FE engine was used in lexus 300 SUV's and some stuff that I found about the sensor location for this engine was that Bank 2 is the front sensor in the engine compartment, and bank1 was the sensor closer to the passenger space. I hope this is true because it will be alot easier to replace.

[bud4ya]

Hey guys I got mine out no problem. The sensor I put in looked different from what was in there but I am sure that is because it was a different make. I had to disconnect the battery to make the check engine light go off. Was I correct in doing that? It has not come back on and we have put about 300 miles on it.

I could not believe how easy it came out. I gave it a some muscle and bingo I heard a snap (Thinking or great I broke something) and reached up in and it unscrewed.

I did dose it with PB blaster before hand

Thanks for the input

[Tones]

Thanks for the followup. The Bosch I used also looked different from the OEM. Congrats on doing the job yourself and saving the money.

[tjdmax]

I replaced the front O2 sensor. Not that hard to do. The first sensors I bought was a generic sensor that had to be spliced to the old connector. Price was right, but sensor didn't work. Ended up sending that one back and getting a Denso model with the OEM connector. About a five minute job check engine light clear after I disconnected the battery. Now I have a VSC light on. I took the car to the dealer originally to find the cause for the VSC light which they said was do to the Check engine light. Does any one know if there is separate testing for the VSC, and how can you find the problem.