Oxygen sensors?

Welcome to 2CarPros.

That is correct. There are a total of four. You have two upstream and two down stream. Each bank of the engine (there are two banks) has two sensors. I attached a picture showing locations.

Here is a link that shows how one is replaced:

https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor

Here are the directions specific to your vehicle. The first set of directions and pictures 2 and 3 show how to replace sensor 1 for both the front and rear banks.
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Special Tools Required
O2 sensor socket wrench, Snap-on YA8875 or SWR2, or equivalent, commercially available

Front Bank (Bank 2)

1. Disconnect the front A/F sensor 6P connector (A), then remove the A/F sensor (B).


pic 2



2. Install the parts in the reverse order of removal.

Rear Bank (Bank 1)

1. Disconnect the rear A/F sensor 6P connector (A), then remove the rear A/F sensor (B).


pic 3



2. Install the parts in the reverse order of removal.

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Here are the directions for sensor 2. Each bank has one. These are the heated sensors. Pics 4 and 5 correlate with these directions.

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Secondary HO2S Replacement

Special Tools Required
O2 sensor socket wrench, Snap-on YA8875 or SWR2, or equivalent, commercially available

Front Bank (Bank 2)

1. Disconnect the front secondary H02S 4P connector (A), then remove the front secondary HO2S (B).


pic 4



2. Install the parts in the reverse order of removal.

Rear Bank (Bank 1)

1. Disconnect the rear secondary HO2S4P connector (A), then remove the rear secondary HO2S (B).


pic 5



2. Install the parts in the reverse order of removal.

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Please keep in mind, it isn't normal for all of these to go bad at the same time. If you have a diagnostic trouble code indicating an issue with an O2 sensor, let me know what it is and I can direct you better.

I hope this helps. Let me know if you have other questions or need help.

Take care,
Joe

I need to replace the:

Front Air/Fuel Ratio Sensor Bank 2 Sensor 1 Heater System Malfunction.

Rear Air/Fuel Ratio Sensor Bank 2 Sensor 1 VS Line High Voltage.

How do I know I am ordering the right parts?

What you have sounds more like a shorted wiring harness not bad sensors. Also, the front and rear sensors would have different designations. Both would not be B2 S1. Could you post the actual codes you have? That would allow for a better idea of the problem.

Hi Steve.

Thanks for responding to my posting.

Here are the exact wording of the codes:

Rear Air/Fuel Ratio Sensor Bank 2 Sensor 1 VS Line High Voltage
Error Code: P2254.

Front Air/Fuel Ratio Sensor Bank 2 Sensor 1 Heater System Malfunction
Error Code: P0154.
Consequences: Black smoke from exhaust.

I have also included a screenshot of the code reading.

If those are the correct codes the description for both are wrong.

P2254: Front A/F Sensor VS Circuit High Voltage B2S1.
P0154: 02 Sensor No Activity Circuit B2S1.

What it means is that the sensor is shorted to supply or bias voltage and is staying there.
I would check the wiring for the sensor and be sure it is not damaged or chewed on. If the wiring looks okay then the easiest test would be to replace that sensor.

The sensor in question will be the first one at the top of the exhaust manifold closest to the radiator when you open the hood.

I replaced the Bank 1 Sensor on the vehicle, but I cannot locate the Bank 2 location to replace it. I still got the code to replace the Bank 2 sensor. I need help. Thank you.

Hello,

The upstream O2 sensors for both bank 1 and bank 2 are going to be located in the exhaust manifold before the catalytic converter. Both downstream O2 sensors for bank1 and bank 2 are going to be in the exhaust pipe after the catalytic converter. I have included a diagram for you in the diagrams down below.

Thanks,
Alex
2CarPros

location of the oxygen sensor on a 2001 honda odyssey van

Primary Heated Oxygen Sensor (HO2S)In exhaust pipe, forward of catalytic converter.

Secondary Heated Oxygen Sensor (HO2S)On catalytic converter. Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.

How to replace the oxygen sensor?

Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.

https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor

My battery will not stay charged and now i have a p0135 code. what can i do?

They could be related. P0135 is a B1 S1 heater circuit malfunction. Could be the heater wires got close to the exhaust or to a spot on the block and melted/rubbed through the insulation. That short could be why the battery will not charge, because a short is pulling all the power.
I would start with a visual inspection of the O2 sensors wiring and see if you locate a bare spot, start at the sensor and work up the harness.

This is basically the same engine as a 1998 honda accord. I had the check engine light come on and Autozone told me it was a P0135 and that I needed a new oxygen sensor. I purchased a Bosch direct fit and had it in without trouble. But.. the check engine light remained. I took it to Autozone to have them clear it to no avail. It came right back on. I went home and double checked everything. No loose or burnt wires. Connector snapped on tightly.

Googling the code, I've come to realize that the code is specifically for "Oxygen Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)". This vehicle only has two O2 sensors and I verified that I had in fact replaced the one before the Cat.

This leads me to believe that the problem is in the circuit away from the O2 sensor. I know that there is a relay that provides power to the O2 sensor but it also provides power to the other O2 sensor and a couple of other sensors.

I might check for voltage in the wires tomorrow, but I'm pretty sure I know what I'll get. (I'll have to clamp the wires while a friend turns the key to on.)

Ideas on which relay to check? Which one is it?
Any other ideas?

Hi tubergonz,

I don't think there is any relays involved. Check the fuses at underhood fuse box.

The grounding of the circuit is by the ECM.

"Check the fuses at underhood fuse box. "

Wouldn't I get more error codes? I understand several sensors get power thru the same fuse.

Running thru the possibilities, if a fuse replacement works great, but what if the fuse blows out again?
I've already checked the harness to the o2 sensor, but not the others for cuts, burns.

Dang it. I checked all the fuses and none were blown.
I can only assume that there is an open circuit.
According to the Haynes manual for 98-99 accords, if the relay had failed then the engine mount control solenoid wouldn't have worked either.

I've run out of ideas.

Hi tubergonz,

The syatem used on your car might have the HO2S getting its power from the main relay.

Check for power at the sensor coupler before looking for the fuses.

If you have a Yellow/Black wire, it should have battery voltage when ignition switch is turned on.

Next to it is the Orange wire and it goes to the ECM.

Measure the resistance of HO2S across the pins, you should get between 10 to 40 ohms. Hope you have wired the sensor correctly.