2002 MPV O2 sensor replacement

[jojo]

2002 MPV check engine light on. took to Advance Auto Parts and did OBD scanning(free), got following code:
P0051 HO2S Bank 2 Sen 1 Heater Circuit Low.

went under the car and found two sensors that sit on the exhaust pipeline: one roughly faces the center of the radiator(also has green wrap for the 4 wires), the other is down near the bottom of the exhaust pipeline(has black wrap for the wires).

I was told there are four sensors, but couldn't see the other two, presumely they are located in the rear. Am I right? if so, could somebody tell me which one I should replace? Many thanks!

Eearly this year I paid the dealer ~$260 for a spark plug replacement($2.53 for the part).

[bubba]

The sensors that you are seeing from the bottom as you describe are the Bank 1 and 2 but are both Sensor 2's. The O2 that you need to replace with the bad heater is located at the very top of the exhaust manifold on the side of the engine nearest the radiator or front of van. Don't try to see visually but with cold engine stick your hand down between the engine and radiator and find the exhaust manifold. A little probing should locate the sensor sticking out of it. It can be seen from the underside and once you locate it by feel you should be able to find from underneath with a little light up in there.

[subearu]

Though you could clear the code (or let it go away on its own after a few driving "cycles"), it could be an anomoly.

One thing to check also: you aren't getting any rough idle or misfires?

-Brian

[jojo]

since everything seems to be normal, did not pay much attention to this problem.

got BOSCH OEM part a few weeks ago, and started to work today. it did take me a while to remove the broken one. once this one was off, it's relatvely easy to put new one one. now, the red light goes away thanks both for the help!

[venitafg]

I need to replace the two from O2 sensors, and am getting conflicting info. Some say they are the same Bosch part and others have two different Bosch numbers. Also does anyone have a diagram.

[bubba]

You are needing to replace both front O2 sensors? Why?
The front O2 sensors for the right and left banks of the engine are in the exhaust manifold very near where the manifold attaches to the cylinder head. The ones on each side further down the exhaust pipes and easily seen from under the van are commonly refered to as the rear sensors. Easy to get the the rear ones. Front ones are quite a bit harder to access.
Am sure can get you a diagram of where the four sensors are located but just very curious as to why the need to replace???
I think that the main difference in using the Bosch is going to be if they are a direct replacement with connectors included or are univeral splice in units. The direct replacements will have a different part number as the harness length and most often the connector is different. Universal ones would be the same as then just splice into the harness. Would avoid them as much as possible. Not good to splice in a sensor as sensitive to voltage and resistance variations as the O2 sensors are. Direct fit from Bosch would be acceptable. OE would be even better.

[venitafg]

Thanks for the info. The codes indicated that both front O2 sensors are bad - the engine surging and wants to cut off once it is warm.

[cpapashley]

[hypomac]

Same P0051 happen to my 2003 MPV.
replaced with Bosch O2 sensor 15708 for $55.99+tax.
no need to splice. CEL gone.
Thanks everyone for tips!!!

[cpapashley]

[tom66seattle]

Had P0051 code. Changed left, front o2 sensor. CEL is off. However, OBD indicates pending error.

Have driven 5 x's CEL still off and pending error.

Should I be concerned? Any ideas what is going on?

Thanks.

[pickupjason]

got p0051 code on my sister's 02 MPV...
bought the bosch 15708 at autozone for 55.99 plus tax..., however, they don't have it in stock at the store near my house, they have to transfer it from their warehouse..

The location for the sensor itself is not bad, easy to reach and easy to work from underneath of the car. However, the conector is another story, the location is hard to reach. I spent 10 mins to pull the connecter out with help from brother in law! Once the sensor is out, it's quite straight forward since the Bosch sensor is simply plug and play.

However, when I got everything done and went start the engine, the check engine light is still on. I figured I need to go to autozone to get the code erased, I went there and only found out they NO LONGER have the OBDII code reader as a loan-a-tool. If you want to erase the code, you have to BUY it at 150 bucks! and the sales is FINAL!!!!!!!!!! I even went to pepboy and they never have loaner tools and they do sell the same code reader 20 bucks higher than that at autozone..

went back my sister's place with the check engine light on and called my friend who has an autoXray code reader. On my way home, I went pick up the code reader and planned to go back to erase the code tomorrow. Brother-in-law just called, the light is gone!!! I think it might take couple "cycles(start and stop the engine)" for the computer to know that the new sensor is there..

Anyway, thanks for everyone who posted great information here so I could get the right parts and fix the problem without too much trouble...
maybe, it's time to shop for a good OBDII reader....

Jason

[subearu]

Take a look at a ScanGauge for a multi-purpose code reader and information tool.

-Brian

[Niko]

[Madbrad]

thread jack:
Which sensor is bank one, sensor one?