radioman2002

Is there any way to test a camshaft sensor? I have been getting sparodic CPS sensor errors (CEL) since purchasing this 1996 Lunina PD 3.1l. Now I get them all the time, I have removed the sensor and was wondering if there is a way to test using a VOM, or could I see a voltage swing if I put the sensor near a magnet? The crankcase sensor is also giving me an error code, is there something common, or do I need to pull that too to test. My tools are a code reader and a VOM. Thanks.

richtazz

There is no easy way to test a cam sensor that is intermittent. The windings break down from heat, and cause them to malfunction. Then when they cool down, they will work until the cycle is repeated.

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radioman2002

The sensor is no longer intermittant, if I reset the computer, the code pops up immediatly. I just don't want to buy a sensor and find it's a wiring harness problem. Correct me if I am wrong, but doesn't the sensor react to a magnetic field? So if I put an Ohm meter across the windings, I should see a meter fluctuation when a magnet passes by. What is the correct Ohm readings, or range? This sounds similar to Chryslers original no points electronic ignition distributor of the mid to late 70's. I know this sounds like petty troubleshooting by today's standards, but as an electronics tech, I like to find the real problem before moving on.

tblake

i think the sensor has the magnet internlly, and a coil of wire. and much like a wheel speed sensor produces a weak AC voltage when anything metallic passes in front of it. the quicker it moves, the higher the frequency and amplitude. Someone correct me if im wrong.

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RCSpeed

If the sensor is a 2 wire version, it is called a variable reluctance type. It has a magnet surrounded by a coil of wire. To test, remove the sensor completely from the car. Hook your VOM (digital??) to the 3 wires of the sensor and select A/c volts. As you pass a metal object across the front of the sensor, it should develop a momentary spike of voltage. The faster you do it, the higher the voltage. You should see at least 100 mV and possibly a couple of volts with quick movement.
If it is the 3 wire version. Leave it in the block. The wires are power, ground, and signal. It is a Hall-Effect type. This should have 5 volts feeding it. Check the harness with the key on for 5V, gnd, and the other wire will be the sig.
If that's good, hook it all back up and "backprobe" the sensor connector on the signal wire. While the eng. is running, you will see some fluctuation on the voltmeter. It might be up around 5 V or it might be around 0V. Usually they start at 5 volt and get "pulled" down to 0V when the trigger on the cam goes by. On an O-scope, its a very short square wave. If you have an o-scope, check it with that. Input mode-DC.
HTH