Which side did you replace, radiator or firewall side?

 

Firewall side behind the catalytic converter. Thanks

 

Do you have a scanner to monitor data?

 

Sorry, no scanner. I checked visually for air leaks and didn’t see Anthony out today the ordinary. . I don’t get it. Thinking Of changing the O2 sensor by the radiator.

 

Bank 1 would be the firewall side try changing out sensor 1 as well

 

Thanks. so change out bank 1 sensor 1? (The one on top). And leave bank 2 (radiator side ) alone.

 

Yup, b1 s1 is much easier to get to the s2. Just use the O2 sensor socket with an extension

 

Awesome. I will get it. I was on rock auto website and when I add the part to my cart there was a disclaimer stating the the manufacture suggests replacing O2 sensors in pairs (both upstream or both down stream) an older slower sensor can cause an imbalance in the engine management system. This is where I’m getting a little confused now. Should I be changing the other downstream one (bank 2) or the upstream one in bank 1 sensor 1. Are the down streams correlated with each other?

 

I am not familiar with that disclaimer as I just went to my local autozone and grabbed mine. But I'm sure you should be fine. If the issue is with bank 1 just focus on that to solve the code and then you can deal with bank 2 after.

 

Denso or NTK O2 sensors are good brands for Honda. Not a fan of Bosch or any others.

 

@Nail Grease When you're changing out b1s2, can you yank the clips free to be able to pull everything up through the engine comp.?

 

I simply pry the old wire holders loose, break if necessary. Certainly depress the clip to release the electrical connection. The vehicle wire harness (female side) has its own holder. This can be carefully released by moving a small plastic lever away from the holder. This may allow you to use both hands to pull apart connection. If the O2 sensor does not come with new wire holders, I’ve use tie straps to hold wire at these points.

 

Can I yank the wire holders free tho?

 

Never tried. I don’t know the result if these will actually break free cleanly and without bending the holder.

 

It's a fairly tight spot for the 2010

 

So, thanks to the space constraints yanking does nothing, however if you cut the connector off the wire you can just pull straight through. And then just zip tie the excess when reinstalling the new sensor.

 

Zip ties FTW! 🤠👍

 

Finally changed the Bank1 sesnor 1 on my Pilot. Talk about a PIA. Thought it would take 30 min. I was at it for an 1.5 hours and for the life of me I couldn't get the electrical connection disconnected. I searched high and low for youtube and tips before starting and this looked so simple. I did a google search and found a thread from here for 2003-2008 pilot and sure enough it was a similar procedure (see link below) . I'm writing this so I can help some one. if you follow the wire of the 02 sensor, there's a metal plate behind it. if you follow that plate all the way to the driver's side, you will find a 12mm bolt. You have to take this bolt out. For some reason, the connection has a fail safe and won't let you disconnect it unless you do this. As soon as I did this, I had the connection off in 30 seconds. Unfortunately, taking the 02 connection off the metal plate was also a PIA. You need to squeeze the clip and press down and slide it off the plate. Took a few tries and I got it. After this, it took 30 min to change it out and another 30 min to put it back together. I'm so surprised Honda did this. The average person who doesn't look this up would never think of taking the metal plate off the engine. So once changed, I immediately noticed a difference. Before I felt like the Pilot was hauling some cargo and after it felt like it wasn't. The error code said Bank 1 sensor 2, which i changed twice and the light came back on with the same code; I went ahead and changed bank 1 as well and cross my fingers everything seems to be working. I'll post back if something changes I appreciate all the help.

O2 sensor replacement tips

I did a lot of searching and didn't find any real tips for replacing the pre-cat sensors. So I thought I'd pass along a few of my own tips. I just replaced the sensors today due to poor gas mileage. It seemed right after the timing belt and water pump was replaced, it just wasn't running right...

www.piloteers.org

 

Ok, it's been a few days and the engine light came back on. I've replace both oxygen sensors on bank 1 (sensor 1 & 2) and am still getting the check engine light code for the P0139. I'm googling it and another thing it could be is a leaky fuel injector they are saying. Anyone have experience with this. I might have to take it to the shop so the get diagnose it with the meters. I think I would have to replace all 6 injectors if one is faulty. Any advice? Thanks

 

I assume that you have looked for air intake leak or exhaust leak?

 

Thank you for replying. I did a visual check for any disconnected or broken hoses and did not see any.

 

So here’s an update I took it to the Honda dealership to get it further diagnosed. I told him I replaced the O2 sensor twice and the engine light keeps kicking back on. They’re telling me it’s not an original Honda part and that it would need to be replaced and that is the issue and they want to charge me $550 for the 02 sensor. I called NGK to confirm that they are the actual OE supplier to Honda for that part. I spoke to the service Director and he said that they will replace the O2 sensor and if that’s not the issue he would eat the cost. Crazy, they are going to out the same 02 sensor in. They will clear the engine code and the light will come back on after a few days. When I will ask for my $$ back for the sensor because I’m sure it wont be the issue, they will likely tell me to go pound sand. This dealership is a joke.

 

Denso and NTK make quality O2 sensors. I’d take a closer look at the vehicle wire harness and connector. Search for a bent pin, pulled out or broken wire.

 

Thank you. It’s in the dealers hands now. I wonder if the previous mechanic pried the connector of the metal bar to what I think it was attached to and messed it up. When I replaced the top O2 sensor , it took me a minute to realize how to take the connector off the bar and I noticed that the lower sensor connector was right next to the top o2 connector and there was room on the bar for another connector but the Lower wasn’t attached to it and just dangling unsupported.

 

Update for those who might find this helpful. Turns out it was not my O2 sensor. It was an exhaust leak at the Y pipe where it meets the flange (the middle flange). I watched youtube video and used a shop vacuum in reverse to blow air plugging the second exhaust with a rag. I immediately noticed a lot of air coming out at the flange behind the heatsheild. I had it repalced at a muffler shop with a Walker brand Y pipe from O'Reily's. So far so good. This pipe was $150 and is expected to only last 3 years. I also learned my front wheel bearing were bad (56K miles) and that was what was causing the car to run sluggish (as if I was hauling a load). Had those repalced with Honda ones (read bad reviews of aftermarket wheel bearing/hubs and they are PITA to change). To end the , the P0139was an exhaust leak, which I tested with a vacuum (dealer wanted to take everything apart and likely charge me $$$ for new parts since they don't weld). tThanks for the help.

 

did the light turn off after the exhaust leak was replaced/repaired?

 

Hello. yes the light turned off and that was the cause of my whole problem a stupid exhaust leak and it has not come back since. Remember I had to replace the entire Y pipe. The muffler guy said it was common. I still have 62k miles in this Pilot. Have replaced the Y pipe, front wheel bearings, control arm bushings, and all the struts/shocks. Runs like a champ now. If you’re experiencing issues with that code, maybe try to shop vac technique that I did. I put the wheels on oil change, ramps.