2004 MINI COOPER today when started the SERVICE ENGINE SOON light was on along with the EML light on the dash, and wouldnt go above an idle. Drove it down the street and didnt get any better. Parked it at home and left it off for about 10 minutes. When started again, the EML light was off, and it reved like it should. But the SERVICE ENGINE SOON light was still on. Drove it to my local AUTO ZONE and they put their hand held computer diagonostic tool on it and came up with a P1683 code, but they had no way to tell me what that code meant. When I went to leave, the SERVICE ENGINE SOON light was off and everything is fine again, like it used to be. Any idea what that code refers to and what made it do it, and will it do it again?

Remove both battery cables, hold them together without touching the battery, for 30 seconds, then reinstall battery cables. This resets the ECU, then drive normal. See if it helps!

you should retart the systems and get it work properly

The following are descriptions from the Mini-Cooper S owner's manual.

Service Engine Soon "?If the warning lamp comes on
either continuously or intermittently, this indicates a malfunction in the emissions-related electronic systems."

EML light: "Engine electronics ?Malfunction in the engine electronics. You can continue to drive with reduced engine output or engine speed."

Triangle circled by an arrow: "Automatic Stability Control plus
Traction (ASC+T)/Dynamic Stability Control (DSC)
?Indicator lamp flashes: System active: drive and braking forces are regulated.
The indicator lamp stays lit: ASC+T/DSC switched off with button or defective. In the event of a defect: please have the system inspected at your MINI Dealer."

First, inspect the belts to make sure none failed at high RPM. If one broke, inspect any cable or hoses in the plane of the belt to see if there was any damage (e. g., a ripped wire in the ASC+T/DSC system). Second, get a readout of the engine error code. (If you get indications of a major vacuum leak including rough idle, look for a blown head gasket.) If you get something else, please post the results in a comment so we can go to the next step.

Drive it real easy until you get the computer scanned for trouble codes.
The check engine light is telling you the computer has a problem with something that will affect performance and emissions, when it flashes the problem is serious and can damage the engine or engine parts.
The trouble codes will tell a mechanic what to look for and test.

The service engine light is on because the ECU has stored a code. Have someone with a reader check the code to see what needs service.

Did you get an answer to this? My 2004 mini cooper did the EXACT same thing this past Saturday July 18th 2010

That is the indication of an exhaust emissions problem on a Mini from the Great White North. It is the same as Service Engine Soon here in US of A.

Minis have had power steering problems. I wouild contact a dealer and see if theres any updates or service bulletins.

the engine control unit has detected a fault light illuminated which in turn reduces ability to gain high revs as a damage limitation exercise , known as limp home , car requires diagnostic computer to check fault codes to indicate faulty component causing ecu to go into limp home mode

Try reading the obd2 code with your phone and this cheap device