Hey guys. I was doing the a catalytic and oxygen sensors on my dads civic. But when I removed the sensors on there. Both had 4 wires and both were the same length. The replacement ones came with a long wire and short wire. And one is three wire and one is four wire. The lengths work either way but if I remember correctly the bottom o2 sensor should be the 4 wire right?

 

They should both be four wire.

 

does this apply to the basic dx model? I ordered it and asked all the make model trim level and this is what I got. Can’t use the old ones that’s for sure.

 

Wow that’s quite a catalyst meltdown you had there.

Positive. It’s a heated sensor just like the primary one. Should be four wires.

- 12V switched power
- ground
- sensor output to ecu
- heater control to ecu

Perhaps you got some sort of universal replacement sensor? I’ve never personally seen a three wire sensor on a Honda. More importantly, they should be the same as what is coming off of the car.

 

Ok. Thanks. I’ll go to the parts store and get it checked out. Thanks for the feedback. And yea his water pump failed and car overheated and he kept driving like a pendejo. I replaced the water pump and timing components last week and was doing the emissions since his engine light wouldn’t go away. Luckily it’s a Honda and still running with no head gasket issues.

 

Well thats your prob, you have a crack in the header portion of the converter and its probably sending mix signals to the ecu, dumping more few and doo dew down the rabbit.

 

That’s standard on those manifolds from the factory lol.

Often causes a false lean condition since the primary sensor receives fresh air.

 

crack kills

 

Patch up that crack while you have it open, get some quicksteel (it's like JBWeld but for metal) and gob it on there.

Or buy a replacement tri-cat from rockauto and get one that is actually welded steel runners vs cast iron and get rid of that manifold you have now.

The blown out cat might cause you to end up with a rear 02 sensor code.

 

That cat has been replaced. I was just showing the failure of the manifold and cat section. I was asking about the o2 sensors because I got a 3 wire and a 4 wire but both on the car were 4 wire. Thanks for the advice tho but that’s manifold was far from saving lol

 

Well lets answer the original question then.


Both are 4 wire regardless. You go by the part # and what the description of the part says its for and not blindly buy stuff.