I have a em1 si with cel code p300 p301 p303 p1399, I just replaced the plugs,wires,d cap and rotor.....within 20,000kms timing belt water pump and valve adjustment were done at Honda.

I am really getting desperate here, I tested the injectors and they are all working there is spark in all the plugs....what else could it be? I am **** about maintenance and I do oil changes every 5k Kms so I hope Not an engine problem

 

We actually just had this happen with a Honda Odyssey that we replaced the plugs, timing belt and water pump on. We checked through everything and there were no issues. We cleared the codes and it has not come back since.

Not 100% sure why it threw the codes but it hasn't done it again since.

 

disconnect your battery and see if codes come back. did you set your ignition timing? and are you sure you put the correct firing order?

 

i will try and re set my battery. the car has A little bit of a rough idle, i dont know it runs and purrrs like a kitten though!

how do you set the ignition timing? also do you HAVE A PICTURE OF HOW THE WIRES GO INTO THE D-CAP?

 

 

Bump

 

Bump what? did you disconnect the battery and see if the codes came back? Are you spark plug wires correct?

 

^that or you can take the 7.5 amp back up fuse out of the fuse box under the hood for a minute if that and then put it back in. it will reset the computer. then go drive to the store or something and then see if the check engine light comes back on. then get the codes and post them