TEST 4: Testing The Camshaft Position Signal
Now that you have checked the basics, in this last test section we're going to check the actual cam sensor signal with a multimeter.
The camshaft position sensor creates an ON/OFF signal that you and I can see on a multimeter. To be a bit more specific, ON would be when your multimeter reads 5 Volts DC and OFF is going to be when your multimeter reads 0 Volts as the engine is manually cranked.
Since the accuracy of this multimeter test depends on turning the engine manually (using a ratchet wrench with the appropriate socket on the crankshaft pulley) you can not use the starter motor to crank the engine.
If you're using an Oscilloscope, then by all means use the starter motor and check out the cam sensor signal waveform in image 2 of 2 above.
If the camshaft position sensor is bad, then your multimeter will stay stuck reading a single voltage of value as you turn the engine.
IMPORTANT: The camshaft position sensor must be connected to its engine harness connector for this test to work. You'll need to connect your multimeter test lead to a back probe or a wire piercing probe to read the cam signal. You can see an example of a wire piercing probe here: Wire Piercing Probe Review (Power Probe PWPPPPP01) (at: easyautodiagnostics.com).
These are the test steps:
Place your multimeter in Volts DC mode and re-connect the distributor to its electrical connector.
Disconnect the ignition coil from its electrical connector. This is an important safety precaution!
With the red multimeter test lead, probe the TAN/YEL wire of the distributor connector.
The tan with yellow stripe (TAN/YEL) wire connects to the female terminal labeled with the number 3 in the illustration above.
Connect the black multimeter test lead directly on the battery negative (-) terminal.
Turn the ignition key to the ON position and turn the engine by hand using the 1/2" ratchet wrench and appropriate socket on the crankshaft pulley. Do not use the starter motor.
Your multimeter will read an ON/OFF voltage of 5 Volts and 0 Volts (if the camshaft position sensor is functioning correctly).
ON is when the multimeter reads 5 Volts DC and OFF is when it reads 0 Volts DC.
Let's take a look at what your test results mean:
CASE 1: The multimeter read the indicated ON/OFF DC voltage. This is the correct and expected test result and tells you that the camshaft position sensor is functioning correctly.
CASE 2: The multimeter DID NOT read the indicated ON/OFF DC voltage. This test result tells you that the cam sensor defective if you have confirmed that it's getting power and Ground.
If the camshaft position sensor is getting power and Ground, but it's not producing an ON/OFF (5 Volts/0 Volts) signal, then it needs to be replaced.
More 3.0L Chrysler Tutorials
You can find a complete list of tutorials in this index: Chrysler 3.0L Index Of Articles.
- How To Replace The Distributor (1988-2000 3.0L Chrysler).
- How To Test The MAP Sensor (1991-1995 3.0L Chrysler).
- How To Test The Throttle Position Sensor (1991-1995 3.0L Chrysler).
- How To Test For A Broken Timing Belt (1998-2000 3.0L SOHC Chrysler).
- Ignition Distributor System Tests 3.0L Chrysler, Dodge, Plymouth (at: easyautodiagnostics.com).
If this info saved the day, buy me a beer!