DME 7.8 DME 7.80 · Work instruction Display OK

DME 7.8 DME 7.80 Work instruction Display OK If not OK 2 Perform system test for See below small lift 3 Replace TWC Perform system test for small lift Warning! During the system test for small lift, the valves remain at small lift, regardless of the type of driving. Faulty switching conditions can be detected by rough running, just like with misfire detection. If a valve is not switched to small lift, the fault type ’under limit’ is recorded. Several cylinders may be stored as faulty, although only 1 valve on one cylinder is faulty. In order to guarantee safety during repairs, the flat-base tappets of the inlet valves of the entire cylinder bank should be replaced if a fault occurs. A faulty flat-base tappet can be detected because the oxygen sen- sor FR for this cylinder bank enriches the mixture (FR > 1) during acceleration with wide-open throttle ⇒ see drawing below. Differ- ence from the other oxygen sensor > approx. 15 %. In the case of a fault, the flat-base tappets of the inlet valves for the entire cylinder bank must be replaced. 0-62 page 2 2673 P0420 p0420 Printed in Germany, 2000