You may have followed my earlier thread about a stretched timing chain on my 04 EX-L. I had the timing chain repaired and the car is running great. I'm on a trip to upstate NY from my home in the DC area.

Cruising comfortably on the interstate when I encounter a separated truck tire tread. No way to avoid it. 70 mph and cars around me. I straddled it, but it still banged into the bottom of the car. Emission light comes on. Car continues to run fine. I happen to have with me my code reader that I purchased as part of the timing chain adventure. Code is P0141 and that is identified as O2 Heater Wire connection. My understanding is that this is to a second sensor or device by the catalytic converter that is emission related. Is that correct?

I stopped at the next service area (NY Tollway). Looking under the car, I see a dislodged wire - knocked loose, kind of a swayed line, but still intact and loose end. Looks like it was dislodged. There seemed to be no real chance it was going to catch on anything and cause further damage and there is no sign of any leaks or other damage. I continued on another 50 miles to my destination. I stopped at a service station, but the mechanics were gone for the evening. The guys there jacked up the car and slid under to check on the wire. They reported that it was still connected at the front end and disappeared into a hole towards the back, but the wire was not loose. They reattached the clips and reported seeing no other damage. Of course, hard to see without it being up on a lift. Light remains on with the same code (I tried clearing it ... came right back.)

I'm here for a meeting in the morning and then off another 100 miles to a wedding. I head back to DC Sunday afternoon.

So what's the scoop on this fault? Is this something that I have to try to get taken care of up here, or can it wait until I'm back home. The car is going in for a safety sticker and some minor work next week and I could have them take care of this at the same time.

I'm guessing that the emissions are higher without this connected properly, but is there are problem with driving the car for ~500 miles in this condition?

Thanks!

Tom

 

Secondary O2 sensor heater circuit.

Not sure if it's still true in 2004, but probably this doesn't do anything to CONTROL the engine/fuel/anything. It just measures whether your catalyst is still functioning OK. So don't worry about doing any harm.

The wire goes through a hole in the bottom of the car, and plugs into the wiring harness underneath the front passenger seat. Chances are it tore a wire apart somewhere rather than "unplugging" the connector. If you're comfortable with this, you could wait till you get home & try splicing the wire back together. Might not work, but won't hurt to try.

If the wire pulled out from the sensor, I'd buy a new sensor. Probably can't be spliced if there's no bit of wire left sticking out of the sensor. (Actually, if you've never replace it on a 13-year-old car, I'd replace it)

Did you check to see if that's the only code? I'd expect also a P0420 especially if the signal wires pulled apart at the same time.
There's 4 individual wires:
- sensor (+)
- sensor (-)
- heater (2 black wires)

In principle it's not difficult to replace the sensor. In real life, it's usually corroded into the socket & requires soaking in PB Blaster or something like that. Then you have to feed the wire through the floorpan & under the seat.

 

Thanks, Jim. Great information and help.

That's the only code I'm getting. The guy who slipped under the car said it was 'still plugged in at the front and disappeared through a hole in the rear. He said the rear wire was tight, i.e., did not appear to be loose down that hole. From your description, that's the opposite of what we'd expect. The wire should disappear in the front and attach in the back, right? And I could swear he was looking further forward than the front seat, but again, hard to know given how he was checking. Are you sure this would hook up under the front seat on a 04? Maybe I'll see if they can put it up on a lift today and look a little more carefully.

But given the code and the general location of the wire, it all seems to make sense. If it isn't obvious, I'm going to let my guy at home look at this next week.

Thanks again.

Tom

Update: I just reviewed instructions for replacing that sensor and now understand how it is routed to connect under the seat. This all matches what the wire I could see under the car where the clips were dislodged. And given the single code, I'm wondering if the impact with the tire tread may have damaged the actual wire, perhaps affecting only the one to the heater but not the others to the sensor itself. Anyway, I'll try to get it up on a lift where we can actually look. Sounds like even just look at the connection under the front seat takes a bit of doing.

 

Maybe it's different coupe vs. sedan? What car do you have exactly?

 

Ok. Correcting my previous errors and adding information. Yes, Jim, it is the same as you outlined. For some reason I was thinking the CC was behind the front seats, thus the wire running forward was confusing. Obviously I was in lalaland on that one. Anyway, yes it is the wire runs from under the front seat forward to the O2 sensor on the CC.

I'm back from my trip without issues. I checked the wires and they are all intact at both the sensor and connector point under the seat. We put it up on a lift at my local garage and you can see that the tire tread impacted the sensor itself. It appears to have a very slight bend. I'm assuming that messed up the heater circuit and thus just the 0141 code. He says the only thing to do is replace the sensor. No other damage visible.

Turns out my EX-L is a California emission. Who knew? Bought new in MN and has never even been in CA. I do remember it was a Japan assembled car, so perhaps all the EX-L models were set up to meet CA requirements. Regardless, I see that's a more expensive sensor. He got a quote from his parts shop of $220 for the sensor.

When I look at the Denso site, it appears to show this as the downstream sensor:
DEN 234-4363

The non-CA one is 234-4797

The Denso.com (not actually Denso but selling Denso products and linked to the Denso site) shows the 4363 one for $94. I see that model listed on Amazon for $88

The discounted Honda parts sites appear to show the sensor as costing $241.

Does all this make sense?

Tom

 

If you enter your VIN on the discount honda parts site, it will tell you which vehicle you have.

The $241 for the o2 sensor might be for the primary upstream sensor and not the one for the catalytic converter.

 

Oddly enough when I enter the VIN, it shows me both the CA and non-CA sensors. I've tried this on several sites.

And yes, these are the downstream sensors. My mechanic says LEV (on the rear window) signifies that it was a CA emission system. But the VIN doesn't specify one versus the other.

 

The OEM part number for the downstream O2 sensor is 36532-RAA-A02. The OEM price is around $130. Looks like the downstream O2 sensor is for both CA and non-CA emissions.

I think you are looking at the upstream O2 sensor at ~$240.

 

Thought I'd circle back and close the loop on this one. Checked and indeed I have a CA emissions vehicle. As I noted earlier, I found on the Denso site the part number DEN 234-4363. Ordered it from Amazon for $88 plus a few bucks for an offset socket. I was having the exhaust system checked as part of an annual safety inspection at a shop I have used for various work and asked the guys to loosen the sensor. I can easily reach it under the car, but it's hard to get leverage in that position. They were happy to do that for me.

Finally got around to sliding under yesterday. Driving onto a 2x10 provided another 1.5" of clearance. More than enough. 20 minutes later, it was all done. Reset the code and so far all is well.

Less than $100 plus 20 minutes versus over $300 quoted by a local shop ($230 for the sensor).

Thanks everyone for your input and help, especially reassuring me that I didn't need to deal with this 500 miles from home.

Tom

 

Glad it worked out and thanks for posting the outcome.