Question: what is the difference between euro 6 and euro 6d?
Answer: In a nutshell: Euro 6c is the standard for WLTP measurements, while Euro 6d-TEMP and Euro 6d are the ones for RDE measurements. ... By 2020, when Euro 6d takes effect, the allowed deviation between RDE and WLTP is reduced to 43 percent (conformity factor 1.43).