Persistent P0304 Code with Check Engine Light

 Created by: xrayman1961
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 Posted: Aug 14, 2019 03:19AM
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Quote:
Originally Posted by xrayman1961
Hi,
Thank you.  It’s got 61500 miles on it.  I suspect that my cheap code reader is not able to reset the code but I would have thought that after about 50 to 100 miles it would clear.  The last time I had a code and had to replace the small pump for the carbon filter, my reader wouldn’t reset it but it reset itself after about 60 miles.  I’ll try the auto parts store.

thanks again.
Keep us updated..

 Posted: Aug 12, 2019 08:22AM
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Hi,
Thank you.  It’s got 61500 miles on it.  I suspect that my cheap code reader is not able to reset the code but I would have thought that after about 50 to 100 miles it would clear.  The last time I had a code and had to replace the small pump for the carbon filter, my reader wouldn’t reset it but it reset itself after about 60 miles.  I’ll try the auto parts store.

thanks again.

 Posted: Aug 12, 2019 05:17AM
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Quote:
Originally Posted by xrayman1961
We own a 2014 Convertible Mini Cooper S.  About 2 weeks ago, we went out driving and about a half a mile from the house, it started running rough and I got a "Reduced Power" warning.  I returned to the house and started looking up info on this and other forums.  It was a cylinder 4 misfire code and all indications were a need for a coil replacement.  As it was time for an oil change anyway, I ordered the ignition coils, the spark plugs and everything needed for regular maintenance.  The plugs are Bosch and the coils are Delphi.  I did all of the maintenance and replaced the coils and plugs and started up the car - it ran great and the "Reduced Power" warning went away.  It operates well in both normal and Sport mode.  The problem is that the check engine light is on, indicating a cylinder 4 misfire (P0304) and my OBD2 tester will not clear it and I've driven it over 100 miles since doing all of the maintenance.  Is there something else that I am missing?
How many miles on your 2014 R57 Cooper S convertible? Normally, when a condition that caused the error code is corrected, the computer will clear the codes, eventually....  

It sounds like the 'rough running' is gone and the engine is running smoothly? Replacing the plugs and coils is what I would have recommended as a first step.

Perhaps you can go to your nearest national auto parts store and have them check / clear the code. (just want to eliminate the code reader as a possible culprit). They should do this free of charge.

 Posted: Aug 11, 2019 10:31AM
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We own a 2014 Convertible Mini Cooper S.  About 2 weeks ago, we went out driving and about a half a mile from the house, it started running rough and I got a "Reduced Power" warning.  I returned to the house and started looking up info on this and other forums.  It was a cylinder 4 misfire code and all indications were a need for a coil replacement.  As it was time for an oil change anyway, I ordered the ignition coils, the spark plugs and everything needed for regular maintenance.  The plugs are Bosch and the coils are Delphi.  I did all of the maintenance and replaced the coils and plugs and started up the car - it ran great and the "Reduced Power" warning went away.  It operates well in both normal and Sport mode.  The problem is that the check engine light is on, indicating a cylinder 4 misfire (P0304) and my OBD2 tester will not clear it and I've driven it over 100 miles since doing all of the maintenance.  Is there something else that I am missing?