I just got it done today. I had a full head swap done on my d16y7 to d16y8a few months ago. I never got around to putting the exhaust manifold on because I needed the cat to be welded on and an o2 bung to be put on too.

I was throwing a P0131 so I decided to just buy 2 new o2 sensors for when I changed the exhaust manifold. I brought it to a muffler shop and had them weld the cat on and now I'm getting CEL P0141. I bought 2 denso sensors that were direct fit and 2 wire extenders. The o2 sensors are exactly the same if that means anything. It didn't look like I needed to get different ones for the front and back visually but maybe I do?

Also maybe one of the wire extenders has a bad wire in it? That's the only thing I could come up with. Or a bad catalytic converter since it didn't come with o2 bung. I had to get one welded on after the cat. I'm also running a p2p ecu if that helps. This code didn't come up until after the new manifold was put on.

Does anyone have any ideas on what could be wrong?

 

you sure you have a cat? or do you have one of those fake *** cats?
did you look thru it and see the honey comb style guts inside? if there was nothing you bought a fake cat/delete and thats why you got the code.

 

i did this project as well..
did you check if your cat was obd2? (it's circular; not squarish) I bought a obd1 one :/
also did you have your 02 sensor wire extensions cut to reach or direct plug n play?

if you bought an obd2 cat (New) then i'm not sure how your getting a code, most likely you should just have a mechanic reset your cars ecu.
if it wasn't new, check if you can see the honeycombs like addiction2bass said and also shake it;
if it makes noise it's probably broken pieces inside and it's no good.

 

we have rules follow them dont double post

https://www.hondacivicforum.com/foru...611#post729611

 

It's got honey combs inside it I know that much. And I'm pretty sure it's not broken inside because I moved it around a lot and didn't hear anything when picking it up. Unless the ******* mechanic broke it putting it on. It might have been obd1 because there was no o2 bung on the cat itself. I had the mechanic weld it on after the cat. I went to an autozone for an obd2 scanner and reset the codes and the p0141 comes up still. It'll come back after seconds of starting the car.

I think it might be obd1 because I bought the cat off a friend who owned an obd1 civic(I don't remember what year). The cat is circular though so I don't know.

What can be done if the cat is obd1? I mean I'd have to buy a whole new cat and resonator to get and obd2 cat on and I just bought both a few months ago.

Also, there's a lot of extra slack with the o2 wire extenders. The mechanic wrapped the extenders around my transmission and used zip ties so it wouldn't be hanging freely from under my car. If that means anything?

I own a 1999 civic lx 4d, too if that counts for anything, as well.

 

The P0141 is a heater malfunction, either a bad sensor or a wiring problem. First inspect your extension cable and make sure it is assembled properly-- each wire goes from a pin on one end to the same pin on the other end. You could try temporarily plugging the extension into the primary sensor to substitute it for the secondary one . (The primary plug on the harness will be unplugged, so expect to get some P013x codes due to that). Clear the codes and run the engine for a short time and see if the P0141 occurs. If it does plug the car harness secondary plug directly to the primary sensor and try again. No code there means the extension cable is bad.

The heater is the two wires that are the same color on the sensor. There should be about 6 to 40 ohms resistance through the heater. Measure all the way through the extension cable as well as at the sensor plug.

The ECU doesn't begin to actually analyze readings from the sensors until after the engine has been running for a few minutes. So a code that occurs within seconds is not due to the exhaust gas composition or operation of the cat.

 

I wish I had a scanner at hand. Then I could do that, but I guess I could figure out some other way to check.

 

Check whether 7.5A dash fuse 15 is blown.

 

Most likely your going to have to buy a obd2 cat.
When i ran into this situation i was told the obd1 cat can't read the sensor right, and the obd2 cat can.

Welding on the new 02 bung will work, but it cannot read it clearly like the obd2 cat can.. nonetheless, if any of mks or ronj's advice works before mine try them. becuase i'm sure you don't want to spend another $100+ buying a new cat :/

 

It doesn't really matter now guys. An old lady pulled out infront of me while I was going 65 mph and I t-boned her. Completely destroyed my car.