Check Engine Light illumination—combined with a lack of power or a stumble on acceleration—may be caused by the throttle position switch (TPS). Kia released an improved part which should correct this concern.
2011 Kia Optima Problem Reports
RepairPal Verified 2011 Kia Optima Problem Reports
A defective AC compressor clutch assembly can cause excessive noise or vibration when the air conditioning is on. Improved parts are available. Replacing the faulty clutch assembly does not necessitate replacement of the complete AC compressor or evacuation and recharging of the air conditioning system.
Reprogramming the transmission control module with the latest Kia transmission software may fix abnormalities in the automatic transmission and erroneous transmission-related Check Engine Light illumination. Software updates are commonly most effective on newer vehicles. Higher mileage vehicles may exhibit a similar symptom caused by a component failure. However, whenever major transmission repairs are performed the transmission software should be checked and updated as necessary.
After the vehicle has been operated with electrical loads (lights, air conditioning), a weak alternator can cause starting difficulties. In some cases, the original alternator could not sufficiently charge the battery; Kia released a new alternator which can correct this concern.
A faulty door latch assembly may cause one or both front doors to be difficult to open. Replacing the worn latch will commonly correct this problem.