When you test the car engine and light came on code U1118 the reason should be Engine Light ON. The car engine is problematic and it is necessary to fix the car engine soon. The engine U1118 OBD2 may also be activated by burdens earlier down the line. Such as, a dirty MAF sensor might be producing the car to overreact in its fuel-trim adjustments. So, oxygen sensors are likely to report fuel combination problems. Do not use another meaning of the code like automobile dictionary meaning or different car manufacturer’s meaning. The real meaning is linked with the car brand.