I know it's a long shot on here, but I thought there might be some Accord/Honda guys strolling around that might have some insight into the problem.

My 2.4L 2004 Accord EX with 155,000 miles has been nothing but great to me since I purchased it at 78,000 miles in 2006. However, lately, it's come to have a very odd problem:

While driving, as the tank gets close to empty, it'll throw a P0420 code: Catalyst Below Threshold. Most commonly this deals with a bad cat or O2 sensor. However, after putting $20.00 worth of 87-octane in, the code goes away after a drive cycle. It's been doing this pretty consistently since winter.

I don't understand how fuel level could be affecting this and was hoping someone could shed some light on the subject. Thanks, guys!!

its your cars way of saying to quit being cheap and keep it above 1/4 tank, either that or it's trying to say vtec isnt going to work if you dont keep it full

seriously though i'm not sure what the deal is but theres alot of honda guys around where i live, i'll throw it out there later tonight and see if anyone has any ideas



www.driftnamiperformance.com

Agent Omega wrote:. the code goes away after a drive cycle. It's been doing this pretty consistently since winter


thats my friend is because it never goes away(it's stays in "memory codes") unless you go to a shop and they erase it from your computer with a scan tool
i had to fix the same problem on a acura tl 2004 not the same engine but same problem what i did is change the o2 sensor before and after the cat.and it worked
hope it help!







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