Honda Pilot - Honda Pilot Forums banner

1 - 3 of 3 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter #1
I have 2009 Honda Pilot EX-L. Whenever I fill up the tank, the code P0420 shows up. When fuel tank is bellow half, the code disappears. I have been able to duplicate this scenario multiple time. And no, it is not the fuel cap. However, when i drive long distance, 200 to 300 miles, the code does not show up on full tank. It is only when I drive around town with full tank, it show up. Any ideas? I have more than 180K miles on the clock. The spark plug, air filter, etc are new.
 

·
Registered
Joined
·
15 Posts
Probably unrelated to fuel level because P0420 is bank 1 cat converter not functioning properly. At 180K, they're at the end of their lives. You're probably running a bit leaner air/fuel ratio on the highway, a little richer during around town driving.



Cats are expensive. You could start with a spacer on the 02 sensor that pulls the tip of it out of the exhaust stream.
 

·
Registered
Joined
·
482 Posts
Putting a spacer in is illegal and will make the problem worse if you don't get to the root cause. Eventually the cat will plug up and the car won't even run. Don't do that.


I would recommend replacing all four O2 sensors with new NTK sensors. They are the same as the OEM sensors. You can get them at RockAuto or just get the part number from RockAuto and get them on Amazon. O2 sensors are good for around 100-150K miles tops and then they just wear out. In my experience, they will skew and cause the computer to add more fuel than the engine needs. I've seen up to 20% additional fuel. This overworks the cats and slowly destroys them, often without any check engine light as it takes 25% or so to set a lean code. You may actually solve your P0420 code with new sensors but its possible the cat may be too far gone. Regardless, if you go to the trouble and expense to replace the cats you would want new O2 sensors on it anyway. Starting with the O2's is cheaper. Then replace your cats if the P0420 returns.



As mentioned, the P0420 has nothing to do with getting fuel. It's just coincidental.
 
1 - 3 of 3 Posts
Top