notaloafer

I was cruising yesterday around 40 mph, minding my own business when the good ol' CEL came on. Pulled the code and got P0141 - high voltage Secondary Heated O2 Sensor (rich mixture?).

I've seen quite a few people on here say that theirs was destroyed when the catalytic converter's internals came apart. If I pull the sensor and find that it's not banged up physically, should I just replace it and see what happens? Autozone has a Bosch sensor that someone else on here used (there's a DIY) for $50 compared to the expensive OEM one.

Now if I pull it out and the head has been chopped off/dented, does that mean I'm looking at replacing the catalytic converter too?

I found similar threads on here, but none of the cars were stock. I created this one because mine is 100% stock. 128,000 miles.

Another thing I'd like to add is that yesterday was the first day the weather dropped below freezing this season (22 degrees out). I'm guessing something finally just snapped under the cold conditions? Not sure if that detail matters.

Stuff I've done recently: changed out a couple of worn vacuum tubes, changed PCV valve (used OEM), wired in a new head unit. All about... 500 miles ago.

Utah S2K

Reset your ECM using a scan tool or pulling fuse 25 (under dash 7.5 Amp). You can also disconnect the battery for a few minutes but easiest to pull the fuse. Restart the car. If no code thrown it's an acceptable intermit ant failure. You may want to reseat the 02 connector at the sensor; it's a 4 pin. May have lost contact due to cold temp contraction of the metal contacts. ( wiggle it to get better contact). If code resets reseat the ECM connector, you may have moved it pulling wires for your head unit. Last choice is a 02 replacement. My bet is the ECM connector, particularly if you messed with speakers.

Utah

P.S. Thanks for providing details which may appear to be irrelevant!

iamxpl

take a look at the cat. if its broken apart, then it may have crushed your O2 sensor. and if that is the case and you have less than 80k miles its covered under warranty.

notaloafer

Whoa thanks for the tips. I'll go try it right now. By the way, what is an "intermit ant failure?"

Also where is the ECM connector? Is it the silver metal box underneath the head unit? I was definitely putting some pressure on it trying to jam all the wires of my head unit back into place.

Also another detail that may or may not be relevant... my passenger door speaker went out the other day too - seemingly randomly. The tweeter is working but the door speaker is ka-put. seems to be cutting in/out randomly. I'm going to pull the panel to see what's going on today as well since because the tweeter is working, my guess is a wire came loose in the door.

Utah S2K

Sorry for my typo : Intermittent. It is possible for a flake of carbon to hard set a CEL. It leaves but CEL stays. Fuse 25 is in the under dash fuse relay block. Sit in the drivers seat. It is the box above you left knee. 25 is on the right row of fuses 2 or 3 down fom the top. Can't remember which one. The slots are numbered. The ECM is the brain of the car and is located behind a panel just in front of the drivers side door. To remove this panel you first pull up the door sill trim. Wrap a medium flat head screwdriver with some tape (prevents scratching). Gently pry up the sill trim starting at the front. There are 3 blind push fasteners which will release as you pull up on thesill. The front ECM cover trim piece can now be removed. This piece has 3 fasteners as well...all different. You need to remove a push connector just in front of the door at the bottom, inside car. Next the is one you get to outside the car. This trim piece wraps around the front door edge sheet metal. From outside the car pull up the bottom of the window rubber window seal to expose the second push pin. Remove it. The 3rd connector pin is blind like the ones in the sill plate. It is located at the front edge near the bottom of the trim. Pull on the trim then slide over the door edge sheet metal (left).You can't miss the ECM or connector now .

Utah

P.S. Speaker is unrelated on that side of the car.

notaloafer

Okay so I took your first set of advice and just did a fuse pull to reset the CEL. I drove ~25 miles today and it hasn't come back on. Should I just ignore it at this point if it does not come back on again? I don't think my catalytic converter is bad - there is no rattling sound coming from it when the vehicle is on, and the exhaust system sounds just as normal as it ever has.

Thanks

Utah S2K

From Helm Manual (I.e. Honda Factory Manual) for MY 00 and 01 page 11-60

DTC troubleshooting

DTC P0141: Secondary HO2S (Sensor 2)

1) Reset ECM (see page 11-4)
2) Start the engine
Is DTC P0135 or DTC P0141 indicated?
Yes- Go to step 3
No- intermittent failure, system is OK at this time. Check for poor connection or loose wires at the Secondary 02 sensor or ECM

When I post I try and provide factual information you may not have at your fingertips like I do. The factory says ignore it; not me.

Utah

notaloafer

Last night ~100 miles later, the light popped up again when driving. However when I drove it yesterday during the day (above freezing the entire time) I had zero issues. It was freezing last night and came up immediately after I started driving after letting it warm up.

I'll follow your advice and check the connections. I tapped on the catalytic converter yesterday when I was underneath changing differential fluid and transmission fluid, and it appears to be solid - no jiggling or moving around inside. I saw that the boot on the O2 sensor was a little bit exposed (it pulled up a bit) so I'll try and re-seat and check the connectors today.

Thanks for the troubleshooting advice!

notaloafer

Okay so I replaced the O2 sensor with Bosch Part # 15733 at Autozone (there were threads on here that this universal sensor is a good alternative to the Honda OEM one).

Before when I would reset the CEL, it would take several miles for the light to pop back up again. After I replaced the sensor, I barely made it half a block before the CEL came back on again, with the new sensor.

I noticed that when I was putting in the new sensor, that the honeycomb had made it's way up to the hole where the O2 sensor is (I'm guessing that is what killed the last one). I had to push the comb back in order to get the wider Bosch sensor in. I also noticed the "death rattle" when I started the car, indicating that the catalytic converter's honeycomb has come loose. My warranty is up on it. What should I do at this point? Did the CEL come right back on because the new sensor is getting jammed up immediately by the comb?

Billman250

You cannot push the comb back, it will immediately damage the new sensor.

Your cat is junk.

Put a spacer on the new o2 it will prevent it from breaking.