The 3‐level charge‐pumping technique for characterizing electron and hole capture cross sections of fast interface traps in metal‐oxide−semiconductor devices is studied via quasistatic one‐dimensional numerical simulation. In general, these simulations confirm our understanding of the operation of the 3‐level technique for carrier capture and emission. The simulations show that the previously developed simplified analysis of 3‐level charge pumping is reasonably accurate in the emission regime. In contrast, previous simple analysis of the capture regime is found to be in error. For quantitatively accurate results, the effect of the trapped charge on band bending must be included. A revised analytical approach for the capture regime is developed which corrects this error.