Oxygen sensor - collar around it??

Are you using an oxygen sensor socket?

 

The repair manual suggests that you remove the inverter first, for access. It also suggests the use of a special service tool, part number 09224-00010.

BTW, the upstream sensor is called an air/fuel ratio sensor. I hope that your replacement part is the same - and not an oxygen sensor.

 

The computer's database is wrong. I suggest that you buy the correct part.

If you look at a Toyota dealer's parts website (for example, toyotaworld.com) you will see that there are different descriptions and different pricing for the two sensors. An air/fuel ratio sensor has different operating parameters compared to an oxygen sensor. The A/F ratio sensor price is $162 at that particular dealer.

You can obtain Toyota part numbering at toyodiy.com

Yes, you apparently need a thinner wall socket to have a chance of extracting the old part. Good luck.

 

As Patrick said, the upstream sensor is actually a Wide A/F sensor, not a regular O2 sensor like the downstream one.

 

Does anyone know if there is any reason to have the collar around the sensor other than creating the need for a special tool to remove it? I hope there is a real technical reason cause that looks like a big pain for the customer and a revenue generator for the stealership.

 

I don't see the collar in the repair manual. I am wondering whether the OP has tried to pull on the collar using long-nose pliers? Perhaps it is a heat shield for the sensor?

 

Just curious why changing the sensor for the 2007 Prius? Seems still pretty new car.

 

I assume the odometer has logged high miles and the engine ECU logged DTC P0420 (which shows a defective catalytic converter), so the OP is probably trying to replace the A/F ratio sensor to see if that will help.

 

Lots of Autozone-type stores will let you borrow (with deposit) the right O2 sensor socket. Or try this cheap one -- note how the outer socket wall has been milled down. Don't forget the anti-seize!

I don't know why they have that collar around it, heat shielding perhaps.

 

The only issue that I can see is that a 7/8" o2 socket is ever so slightly larger than a 22mm o2 socket like the OTC special tool. So even a thin walled 7/8" socket like the OEM may have .01" too large a diameter. Still, it is worth checking around at Autozone/Pepboys/O'Reilly etc to borrow one that will work -- they don't like the dealers either.

Another theory on that collar is that it helps keeps the socket from slipping off when you are using a 3' breaker bar to get it loose

 

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WAG - thermal barrier?

DBCassidy