Moin, my C 30 1.6 d (Bj. 02/07) shows the error message “DSTC failed, maintenance required, reduced engine power”. After a restart everything is ok again, but after a few km ……….! Various errors like AGR, DSTC and others were read out. My friend wants to keep the little one for maybe three days now to systematically search for the error. So far so bad. We have now agreed on the DSTC-Steu get to exchange, because (and therefore my thread) Volvo replaces the control unit to a bulwark (50%). Cost me about 400 €. If your DSTC also sometimes zits around, you should perhaps ask if there is also an exchange on bulwark with your model. However, this regulation applies only until 23.(?) February!