A diagnosis technique is presented to locate seven types of single faults in scan chains, including stuck-at faults and timing faults. This technique implements the Jump Simulation, a novel parallel simulation technique, to quickly search for the upper and lower bounds of the fault. Regardless of the scan chain length, Jump Simulation packs multiple simulations into one so the simulation time is short. In addition, Jump Simulation tightens the bounds by observing the primary outputs and scan outputs of good chains, which are ignored by most previous techniques. Experiments on ISCAS'89 benchmark circuits show that, on the average, only three failing patterns are needed to locate faults within ten scan cells. The proposed technique is still very effective when failure data is truncated due to limited ATE memory.