I recently purchased a 98 Accord EX 4 cylinder Automatic trans. The CEL was on and AZ pulled about 4 codes that appearanly related to a faulty/loose gas cap. Well, the previous owner had pulled away from a gas station with the knozzle still in the fuller neck so the gas cap wasn't seating right. I have reseated the inner sleave on the filler neck and did my best to reshape the outer threaded portion of the neck. It feels like the gas cap goes on all the way now. However, after resetting the codes and driving it for a little while, the CEL came on again. This time, it's the P0420 code. I had AZ reset the code, and when I first start up the car, it idles low and rough for a short while, then it rights itself and the car runs fine. Unfortunately, after driving it for a short while, the P0420 code comes back. So, can this code still be related to a problem with the gas cap or it not seating properly?? Thanks in advance.

 

P0420 indicates a bad cat converter. p1456 is evap leak aka "gas cap loose" most of the time. If you constantly get a p1456 your better off taking it to the dealer for diag. I would say that they were two seperate issues.

 

If its a 4 cyl. I would say you need a new cat. I have seen many 4 cyl Accords with cat efficiency codes. To make sure the check engine light doesn't come back on, I would recommend a Honda cat and replacement of the O2 sensors too.

 

Just the cat, no need to replace the o2 sensors.

 

thanks for the replys. I've also seen on a thread where someone said it may be the egr valve? They said something about drilling out the valve cover?? Anyone heard of that??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by northworm &raquo;</TD></TR><TR><TD CLASS="quote">thanks for the replys. I've also seen on a thread where someone said it may be the egr valve? They said something about drilling out the valve cover?? Anyone heard of that??</TD></TR></TABLE>
P0420 has to do with the cat and nothing else. The egr system has it's own codes.

 

Cool, Thanks for the quick reply! Also, Would anyone know why after AZ resets the code, when I start my car it will idle rough for a couple of minutes?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by northworm &raquo;</TD></TR><TR><TD CLASS="quote">Cool, Thanks for the quick reply! Also, Would anyone know why after AZ resets the code, when I start my car it will idle rough for a couple of minutes?</TD></TR></TABLE>
When they reset the ecu it looses all of its stored sensor information. It takes it a little time to relearn their parameters.