The engine smoothness control facility balances out the speed fluctuations of the individual cylinders caused by different (as a result of injector tolerances) injection quantities and degrees of cylinder efficiency. The fluctuations in engine speed are balanced out by rapid application of controlled corrected injection quantities for each cylinder. The corrected injection quantity is calculated for each operating cycle and each cylinder. The signal from the crankshaft sensor is the basis of the calculation.
Fault code ”smooth running controller” is stored in the DDE control module if the correction quantity at a cylinder exceeds a defined limit.