Crankshaft sensors usually either work or they don't. However, using a vom meter, you can test the resistance of the sensor to see if its working.
Faulty sensor get it replaced if not check to make sure wire isn't shorting out
Check for loose connection of positive cable at battery, crankshaft position sensor faulty, or ignition module faulty.
Check to see if the wiring is damaged.
PO335 Crankshaft Position Sensor Circuit.Possible causes: Faulty crankshaft position sensorLoose or shorted wiring to sensorSignal plate damagedBad starter motorWeak battery
check crankshaft sensor sensor
check the crankshaft sensor or the cam sensor.
The crankshaft sensor in your 1990 former Roche is located on the front of the engine. The best way to test your crankshaft sensor is to hook the engine to a Dyno tester.
A bad crankshaft sensor will cause a vehicle not to start. The sensor sends a pulse to the system so that the spark plugs fire at the precise moment. If the sensor is intermittent then sometimes the vehicle wont start for no apparent reason, or may turn off while driving. Not sure if the question is about camshaft sensors or crankshaft sensors. Some vehicles will run with the camshaft sensor faulty or unplugged. But it would illuminate the "Check Engine" light.
Check
check the crankshaft sensor
Yes, a faulty O2 sensor will cause the check engine light to come on. Many auto parts stores will plug in an ODBII code reader to your Expedition to get the "trouble code" that tells you which sensor (there are 4) is faulty, free of charge.
The check engine light will illuminate. The code(s) will direct you to the faulty sensor.