The engine may fail to start due to an electrically shorted sensor. Some of the sensors may internally short and not blow any fuses. A technician may find no spark and no operation of the fuel injectors in the diagnosis. One way a technician may isolate the defective sensor is by disconnecting sensors one by one to see if the engine starts.
Car Problem Reports
Mazda B3000 Crank but No Start Condition and No Spark
Mazda B3000 Problem
Visitor, 2004 Mazda B3000, 112,560 mi
Water intrusion into passanger side kick panel fuse box causing a short without blowing the fuse in the starter relay