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.Google+
Car Problem Reports
Mazda B4000 Crank but No Start Condition and No Spark
Mazda B4000 Problem
Visitor, 1994 Mazda B4000, 277,678 mi
A connector to a sensor to the water pump came loose. Had to reconnected and the truck started.