I have a 2002 RL with 130k miles. Just recently the check engine light has started to illuminate. I had Autozone read the obd code which turned out to be P1456 - Evaporative Emissions (EVAP) Control System Leakage (Fuel Tank System)

Doing some research, I found that this code is usually caused by a loose gas cap. The cap that is on there is the original OEM cap. I retightened the cap until I heard 3+ clicks. I pulled the radio fuse and the light went out. My wife drove the car three more times and now the light is back on. What could be causing this to occur? The car doesn't appear to be suffering any performance or MPG loss. I have a replacement OEM cap on order just in case the cap itself is bad. I'm not sure about the chances of that being the case. The only other thing I could think of is that I've read about early 2000 model Hondas/Acuras having bad threads on the fuel filler neck which could cause the EVAP system to leak. Here http://www.crvownersclub.com/TSBs/2004/04-002.pdf is a TSB for CRVs/S2000 that have the problem. I couldn't find a TSB specific to Acura or the RL but I wouldn't be surprised if it applied. Has anybody ever encountered this on the RL?

 

I triggered the P1456 code several times after filling up, even after I thought I had screwed the cap down tight, as evidenced by the "clicking" sound. But what I found is that, my cap was giving me the "clicking" sound before the cap was actually completely tightened (and because it wasn't tight it was triggering the warning). What I have to do is, as I tighten the cap I'll get to the point where it will click initially (don't believe it!), then I grab the cap around the outside and tighten it further by essentially bypassing the clutch that makes the cap slip and cause that clicking sound and force it to turn a few more times - then I'll reach the point where the cap is ACTUALLY tight and I'll get the clicking sound again.

I've never re-triggered the P1456 code since I've been doing this. You're new cap that is coming will probably do the trick anyway.

 

I had this exact same issue. My first gas cap would click and then keep turning. I tripped the light once and my dealer cleared it for me. The second time I did it, I knew I had tightened the cap down and took it in, which they determined the cap was bad. I'm under warranty still on my 2002 RL so I usually take it in, quick and easy replacement cap fixed the issue.

 

Your car probably needs a new o2 sensor,,,part #36535-P5A-A01,,,gonna cost you around $350.00 to replace,,,

Located beneath front right seat on the underbelly of car,,

Good Luck!

RLT

 

It was a bad gas cap. Replaced it and the light went out. Thanks.