05 MCS Auto....My son has had the CEL on for a while now. Changed the fuel cap and the same code was thrown within 100 miles. Can anyone tell me other areas that may be prone to having an evap leak on these vehicles?? Is a smoke test the easiest way to find it ??

 

These are super hard to detect. There is an evaporated vent valve on the passenger side of the engine. It is cheap. But it could also be so many other things. I too have this leak and in 4 years have not been able to locate the leak. I keep passing smog after I reset the codes before it comes back on. I talked with my smog tech and he said this is the only code that is allowed to be stored and still pass. Do you have p0456?

 

Yep thats the code its throwing. Other than the code the thing seems to run just fine....milage hasn't changed, no hesitation or fluid leaks ....

 

Dtml pump, as well as many other items. Gas cap fixed it for me. Seems like many people just live with it as long as car runs fine.

 

'05... and the CEL pops on... I would guess it is time to change the rubber boots for the supercharger... as seen here..

http://www.ecstuning.com/Mini-2004-C...ake/ES2588236/

But yes, a smoke test is the best way to find the mystery leaks.

Motor on!

 

So I got a P0456 Code today on my 03 R53. The gas cap o ring is cracked but doesn't look terrible. Should I swap the cap out and then see what happens? is there anything else I can do at home to diagnose the code before I start throwing parts at it or take it to a shop?

 

If the cap is cracked, it is done. My cap looked perfect and yet it wasn't. I've driven a few thousand miles since replacing it and the code never came back. The cap is the cheapest part to throw at it.

 

can't see the supercharger boots causing a EVAP leak(fuel tank leakage).

--most likely a poor fuel cap sealing issue
--black plastic line runs from fuel tank vent valve to charcoal canister(possibly damaged from hitting something).
---possible faulty vent valve, not likely(usually they work or they don't).
--make sure lines are installed on vent valve properly(did someone install a belt recently??)
--make sure charcoal canister is not cracked/damaged.
--smoke test is best... can be done at vent valve but need to block off the DMTL pump breather.
--if no leaks can be found.....have seen several cases were the DMTL pump gets weak overtime & is not pressurizing the tank properly. DMTL replacement was needed. Not that hard of a job if mechanically inclined.

**only a dealer or BMW/MINI specialty shop with proper diag software can run a fuel tank system test.

CHEERS

 

Sweet, well I got a BMW gas cap (no mini dealer within 75 miles) but the part number seems to be the same. The BMW cap is a bit different from the one on there (which I kind of suspect isn't OEM) but after I cleared the code, it hasn't returned. A plus is the new cap has more of a seal than an O ring so maybe it'll be more durable.

 

I believe that the system that triggers the code is condition based. Meaning it doesn't check it constantly, but is based on usage, mileage, etc. So it may take awhile to prove that it was the cap. Hope it solved it for ya.

 

If needed, 16-11-7-222-391 gas cap here since your dealer is so far away. You can purchase any other parts you need for your MINI HERE.

 

Haha, the real irony is that I had a box of parts arrive from you the same day the check engine light came on. If it had come on 3 days earlier I would have just ordered the cap but I didn't want to pay shipping again.

 

Oh no, I hate when that happens! Next time something like this happens, shoot me a PM, I might be able to help you out.