TEST 2: Verifying The Cam Sensor Is Getting Ground
Now that you have confirmed that the camshaft position sensor is getting power, the next step is to check that the BLK/LT BLU wire (of the distributor connector) is feeding the cam sensor with ground.
The BLK/LT BLU wire of the distributor connector is the one that connects to distributor pin #1 in the illustration above
NOTE: Avoid probing the front of the distributor's connector terminal with the multimeter's test lead (or you run the risk of damaging the terminal). My suggestion to you is to use a back-probe or a wire-piercing probe to test for this voltage. To see what a wire piercing probe looks like, go here: Wire Piercing Probe.
This is what you need to do:
Place your multimeter in Volts DC mode and unplug the distributor assembly from the engine wiring harness connector.
IMPORTANT: This test is done on the engine wiring harness distributor assembly connector and NOT on the distributor assembly's connector. Recall that the engine wiring harness distributor assembly connector has female terminals.
Connect the black multimeter lead to the BLK/LT BLU wire of the distributor's connector. This is the wire that connects to distributor pin #1 in the illustration above.
Connect the RED lead directly on the battery's positive terminal.
Your multimeter should register 12 Volts with or without the Key in the On position (if the BLK/LT BLU wire is feeding the cam sensor with ground).
Let's interpret your test results:
CASE 1: If the multimeter showed 10 to 12 Volts: Then all is good in this circuit and the cam sensor is getting ground.
The next step is check that the cam sensor is creating a camshaft position signal, go to TEST 3: Verifying The Cam Sensor Is Creating A Camshaft Position Signal.
CASE 2: If the multimeter DID NOT show 10 to 12 Volts: This indicates that the cam sensor doesn't have a good path to ground. Without a path to ground, the cam sensor will not work and your 2.5L Chrysler/Dodge will ‘cam but not start’.
Altho' it's beyond the scope of this tutorial, your next step is to find out why this ground is missing and restore it. Repairing the cause of this missing voltage should solve your vehicle's no start problem.
TEST 3: Verifying The Cam Sensor Is Creating A Camshaft Position Signal
Now that you've verified the basics (power and ground to the cam sensor), we're gonna' see if the cam sensor is creating an actual cam position signal.
The tan with yellow stripe (TAN/YEL) wire is the one that carries the cam signal to the PCM. This wire connects to distributor pin #3 in the illustration above.
To see if the cam signal is being generated, we're gonna' tap into this wire with the multimeter.
This is another multimeter test but with a major difference: you have to manually turn the engine to see the cam sensor's signal with your multimeter. For this test you SHOULD NOT use the starter motor to crank the engine.
Why turn the engine over by hand? Because turning the engine over with a socket and ratchet wrench will ensure the accuracy of the cam sensor test with your multimeter. Testing the cam sensor by having the starter cam the engine will not give you an accurate test result.
These are the steps:
Remove the fuel pump relay to disable the fuel pump. This is safety precaution!
Place your multimeter in Volts DC mode.
IMPORTANT: The distributor assembly must be connected to its engine wiring harness connector for this test!
Connect the red multimeter test lead to the TAN/YEL wire with an appropriate tool.
You should use a back-probe or a wire-piercing tool to attach to your multimeter to check for this camshaft position signal (Wire Piercing Probe).
Connect the multimeter's black lead directly on the battery's negative terminal or a good ground point on the engine.
Turn the key to the On Position but don't crank the engine. This will power up the cam sensor.
With an appropriate tool, turn the crankshaft pulley by hand. Do not crank the engine with the key from inside of the vehicle.
If the cam sensor is functioning correctly, your multimeter will register an On/Off voltage signal as you cam the engine by hand. ‘On’ will register 5 Volts on the multimeter and ‘Off’ will register 0.1 Volts.
Let's find out what your test results mean:
CASE 1: If the multimeter registered the On/Off voltage values the whole time you hand cranked the engine: Then the camshaft position sensor is working and is not the cause of your 2.5L Chrysler/Dodge's ‘no start’ condition.
CASE 2: If the multimeter DID NOT register the On/Off voltage values then the camshaft position sensor is BAD and needs to be replaced.
To explain this a bit further: You have:
- Checked/confirmed that the ORG/WHT wire, of the distributor connector, is feeding the cam sensor power (TEST 1).
- Checked/confirmed that the BLK/LT BLU wire is feeding the cam sensor with ground (TEST 2).
- In this test step you confirmed that the sensor is not creating the On/Off voltage signal (On= 5 Volts, Off= .1 Volts).
Taking these 3 specific test results into account, you can conclude the camshaft position sensor on your 2.5L Chrysler (or Dodge) is bad.