How do you know when you have a bad camshaft sensor?

Answer 1

To test a camshaft sensor or a crankshaft sensor you will need a digital multimeter with back probes ( wire peircing probes ) and a friend. Look at the sensor and determine if it has 2 or 3 wires going to it; the procedure is different for each. The main difference is the 2 wire sensor doesn't have power provided to it and the 3 wire sensors do.

2 wire senders are very simple to test. Connect the multimeter set to Volts AC between the 2 wires. It doesn't matter wich probe is to wich wire. Have a friend crank the motor. While cranking the meter should show a fluctuation between aprox 0.3 volts and 1 volt AC. If it does it is functioning correctly.

3 wire senders are a bit more complicated. First it is necessary to figure out wich wire is wich. If you have a good wiring diagram this should be easy to determine, if not you'll have to figure it out for yourself. To do this set your multimeter to Volts DC and turn the key to the on position (not run). Put the negative to ground on the motor or vehicle body and use a backprobe on your positive lead, checking each wire to see wich one shows 12v. Note that some cars provide around 9v rather than battery power. This wire is the positive lead remember it or better yet, mark it. Turn the key off and set your multimeter to ohms and test the other two wires ( start with the black one first or if European the brown one). Test between one wire and ground that there is continuity or low resistance. That is the ground. The other wire is obviously the signal wire. Different cars, mostly dependant upon year, may have different powered signals. Set your meter back to volts DC that will show at least 12v and have your friend crank the engine. You should see a fluctuation of voltage between 9v and 12v. If you don't see a fluctuation retest with the meter set to a lower reading and look for a fluctuation of between 0.3v and 1v. If you see a fluctuating signal your sensor is good.