Need to know where the 2000 Sienna O2 Oxygen sensors are

1/ Check engine light came on.

2/ Private mechanic let me hook up his gizmo to read out what the
problem was.

3/ Readout was something like this [from memory, but the B1S1 is
accurate for sure]

B1S1 O2 SENSOR
B1S1 SHORT or OPEN IN HEATER CIRCUIT

4/ I paid $211 for the part, + labor. He reset the check engine
light with the code reader gizmo.

5/ Now, maybe 50 miles later, the check engine light is back on.

6/ Can anyone point me to a resource on the net which tells or shows
the locations of all 3 or 4 sensors, B1, B2, S1 and S2 ?
I was unable to find same with Google. The mechanic said he knew
B1S1 was the one in the middle of the exhaust manifold, closest to the
radiator, "by experience". I fear he was mistaken.

7/ A good online source of sensors would be welcome too - my plan is
the buy the right one at a discount and have him
put it in for free. I doubt he will be able to take the newly
installed one back for refund.

TIA, QE in NJ

B1 refers to the cylinder bank that the sensor resides in. Bank 1 always
contains cylinders 1,3,5, and so on. Bank 2 has 2,4,6, etc. In your sienna
bank 1 is the bank in the rear of the engine compartment. The way to
determine this is by looking at the intake runners. The first runner will
go either left or right to cylinder #1. Follow the first runner and you
will see which side bank 1 is. This rule follows for all engines I've
worked on.

S1 or S2 refers to the location of the sensor relative to the catalytic
converter. Sensor 1 is in front of the cat, sensor 2 is behind. Thats
about it.

So anyway, if the code was B1S1, then your technician replaced the wrong
sensor. You should be looking at the one in the rear exhaust manifold.

Thank you qslim for the great, clear lessons. I have heard other
ones but theseare the 1st ones I could really understand.

Cheers, QE in NJ
=======================
On Sun, 26 Feb 2006 14:31:48 -0500, "qslim" <Suckers@suckersdotcom>
wrote:

|B1 refers to the cylinder bank that the sensor resides in. Bank 1
always
|contains cylinders 1,3,5, and so on. Bank 2 has 2,4,6, etc. In your
sienna
|bank 1 is the bank in the rear of the engine compartment. The way to
|determine this is by looking at the intake runners. The first runner
will
|go either left or right to cylinder #1. Follow the first runner and
you
|will see which side bank 1 is. This rule follows for all engines I've
|worked on.
|
|S1 or S2 refers to the location of the sensor relative to the
catalytic
|converter. Sensor 1 is in front of the cat, sensor 2 is behind. Thats
|about it.
|
|So anyway, if the code was B1S1, then your technician replaced the
wrong
|sensor. You should be looking at the one in the rear exhaust
manifold.