An anonymous reader writes: Belgian public broadcasting station VRT has discovered that GM Opel dealerships in Belgium seem to be updating engine management code when Zafira cars equipped with the 1.6 litre CDTI diesel engine are brought in for service. After the software change, the nitrogen oxides (NOx) emissions drop sharply, at the cost of reduced power output. Bern University of Applied Sciences and environmental lobby club DUH previously found this model to pass European emissions standards only when the rear wheels are not rotating. When the rear wheels are made to spin along, NOx emissions increase to several times the limit set by European regulations. General Motors denied using defeat devices as well as the update program that seems to be taking place. However, an anonymous mechanic at an Opel dealership states that GM started pushing updates shortly after the Dieselgate scandal broke.