Mitsubishi 4B1 sensing ring change
This TSB applies to 2008-2011 Mitsubishi Outlander four cylinder Lancer, Lancer Sportback, Lancer Evolution and 2011 Outlander Sport. The number of bolts securing the sensing ring to the crankshaft has been reduced from four to three in production beginning Oct. 4, 2011, with engine serial number GR1742.
The bolt hole was eliminated in the crankshaft, but not in the sensing ring.