HI,i have the civic 1.5 lsi with p06 ecu but the original ecu is p04.
What is the different

 

I think that they are the ecu because when you open them there is no difference. Maybe it depends of the market. My friend have P06 with 100hp OEM and my is P04 90hp. You can convert bought to P28 with same components.
And one more thing. Friends car is Canadian market and my Europe. P06 should have 90hp(depends on market).
I hope this will help you.

 

please correct me if I'm wrong, but based on what I can find via google a P04 is OBD0.
I've never heard of or seen a p06 that's OBD0.

Is your P06 chipped?
Do you have a OBD0 to OBD1 conversion?