2008 SMART CABRIOLET Engine# 132.910 Check engine code P2188. Customer complaint was that the Check Engine Light was on. The Mercedes SDS led us the ME-SFI P2188 ( code description- The mixture (cylinder bank 1) is too rich at idle speed) which was only a stored code in the computer memory.We smoke tested the intake and exhaust system for leaks with a smoke machine, and we did not find any. Other probable causes for this code are injection valves, throttle valve actuator, intake manifold pressure sensor, intake air temperature sensor, O2 Sensor upstream of KAT, coolant temp sensor, leaking vacuum hoses,overfilling the fuel tank constantly/oversaturating the fuel tank canister, and checking breather hoses.Fuel pressure testing at idle would also be a good thing to do to see if fuel pressure might be too high. If none of the above is found wrong, an ME flash update is recommended if the ME has not been reflashed as soon as of MBZ flash update 07/2011 2.8 control unit HW version. This car model was updated with that latest flash, therefore it was not needed.All mechanical, collision, and frame work is done here at 14857 Burbank Blvd. Van Nuys, Ca. 91411. Call for your Mercedes Benz service and repair needs. (818) 989-6028. No job is too big or too small. Serving the Los Angeles and San Fernando Valley area since 1975 www.blvdautorepair.com Mercedes Benz repairs for the internet generation done here.