Sorry, I know I have in the wrong section, can mod move to general tech.

Car: 2000 Accord EX V6 California model

Bought Denso 02 sensors from RockAuto and was able to install the upstream sensor easily.

Now working on the downstream (at the CAT) and have a couple of questions.

1. I know the harness leads under the passenger compartment. How EXACTLY do I get to it. Do I need to remove the seat, how much of the carpet needs to be removed and if so, where do I start.

2. The clips that hold the wire on the frame. I broke the clip on the upstream sensor, so I just zip tied it to the bracket on the frame. What's the method to undo the clip, without breaking it. As I think the secondary sensor has 2 clips on the frame before it goes into the passenger area.

Thanks in advance for any advice.

 

OK, I'll move it to GenTech...

I've found those plastic clips are real easy to break after they've been hot. Generic type ties are OK or something you can find at AutoZone-type places. Dealer will have them maybe not too expensive.

I didn't have a V6, but I thought the disconnect plug for the rear O2 sensor was still under the car? It's #18 in this picture, looks like the wire isn't very long, even if it DOES go through the floorpan.

 

Thanks for the info and the move of the thread.

I haven't taken a close look yet underneath the car, but I'll take a look tonight. My searches showed that the wire was the seat, but I didn't take into account the 4 cylinder maybe different. My Chilton manual has been useless for this.

Thanks again for the info.

 

Jim, thank you for the drawing, it helped out. Yes, the 02 harness was underneath the car. When I first looked at it from underneath the front of the car (as I was changing the primary 02) it looked like the secondary wire was leading into the passenger compartment. But my view was partially obstructed and that obstruction was exactly where the harness was located, right behind it.

But, the sensor is frozen on the CAT. I've tried soaking in PB Blaster and also tried removing while hot after a few hours of driving...no go. Using an 02 socket with an extension and 18" breaker bar, but still can't remove it.

Car is going into smog next week, not too worried about it. Car drives much better with the new primary 02, but with 200K on the original sensor, would like the secondary changed too. Might do some preventative maintenance and get a new CAT, as the car does get some rotten egg smells once and awhile. Maybe the muffler shop can put in my 02 sensor while there at it.

 

If you're not getting a check-engine light, that rear O2 sensor and the cat must be working. The rear sensor doesn't do anything for engine-control. It only measures whether the cat is working.