TEST 2: Verifying The Crank Sensor Is Getting Power
Like any other electrical component on your Dodge pickup (van or SUV), the crankshaft position sensor needs power and Ground to work.
In this test section, you'll check that the crank sensor is getting power with your multimeter.
To give you some more specifics, this power is in the form of 5 Volts DC and are provided by the PCM with the key on (and of course with the key on engine running).
Depending on your specific vehicle, the 5V supply wire will be:
- A violet with white stripe (VIO/WHT) →it's the same as the purple with white stripe (PPL/WHT wire.
- An orange (ORG) wire.
This is what you need to do:
- 1
Disconnect the CKP sensor from its connector.
- 2
Ground the black lead of the multimeter directly on the batter negative (-) terminal.
- 3
Switch your multimeter to Volts DC mode.
- 4
Using the red multimeter test lead, gently probe the terminal that connects to the PPL/WHT (or ORG) wire.
NOTE: This test is done on the connector with female terminals, which is the engine wiring harness connector. - 5
Turn the key to the ON position, but don't crank or start the engine.
- 6
Your multimeter should register 4.5 to 5 Volts DC, if all is good and the PCM is feeding power to this circuit.
Let's take a look at your test results:
CASE 1: You got 4.5 to 5 Volts DC. This let's you know that the CKP Sensor is being fed with power from the PCM.
There is still one more test to do, before we can condemn the crank sensor as bad, and that is to test the Ground circuit. Go to: TEST 3: Verifying The Crank Sensor Is Getting Ground
CASE 2: No 4.5 to 5 Volts DC. Recheck your connections and try the test again.
If the multimeter still does not register 5 Volts, then you now have confirmed that the lack of power is the reason why the crank sensor is not working (and so replacing it will not help solve the problem).
Although it's beyond the scope of this article to find the cause of this lack of power (to the crank sensor), solving the issue that is causing these missing 5 Volts will solve the no-start condition of your 3.9L, 5.2L, or 5.9L equipped Dodge pickup (van or SUV).
TEST 3: Verifying The Crank Sensor Is Getting Ground
So far, if you've reached this point, you have:
- TEST 1: Confirmed that the crank sensor is not producing an ON/OFF voltage signal.
- TEST 2: Verified that the PPL/WHT wire of the harness connector is feeding the crank sensor with 5 Volts DC.
In this last test section, you'll check that the sensor is getting Ground with a simple multimeter voltage test.
The wire delivering Ground from the PCM to the crank sensor is the black with light blue stripe (BLK/LT BLU) wire of the sensor's 3 wire engine wiring harness connector.
IMPORTANT: Be very careful not to short this wire to battery voltage, or you'll fry the PCM. Also, do not use a test light to verify this voltage. Use a multimeter.
Alright, this is what you'll need to do:
- 1
Disconnect the CKP sensor from its connector.
- 2
Connect the red lead of the multimeter directly on the batter positive (+) terminal.
- 3
Switch your multimeter to Volts DC mode.
- 4
Using the black multimeter test lead, gently probe the terminal that connects to the BLK/LT BLU wire.
NOTE: This test is done on the connector with female terminals, which is the engine wiring harness connector. - 5
Turn the key to the ON position, but don't crank or start the engine.
- 6
Your multimeter should register 10 to 12 Volts DC, if all is good and the PCM is feeding power to this circuit.
Let's interpret your specific test results:
CASE 1: You go 10 to 12 Volts DC. This test result tells you that the BLK/LT BLU wire is feeding the crank sensor with Ground.
You can conclude that the crank sensor is bad and needs to be replaced if you have confirmed the following:
- TEST 1: You verified the crank sensor is not creating its ON/OFF 5 Volt Signal.
- TEST 2: You confirmed that it's being fed with power (5 Volts).
- This test section: You have verified that it's getting a good Ground.
CASE 2: Multimeter did not register 10 to 12 Volts. Recheck your connections and try the test again.
If the multimeter still does not register 12 Volts, then this result lets you know that the BLK/LT BLU wire is not feeding the crank sensor with Ground.
You have now eliminated the crank sensor as the cause of the no-start condition, since without this Ground, the crank sensor will not work.
More Dodge 3.9L, 5.2L, 5.9L Tutorials
I've been adding a lot of 3.9L V6 and 5.2L/5.9L V8 tutorials for both the full-size Dodge Ram pickups and vans. You can find all the new tutorials in these new indexes:
3.9L V6 Pickups And Vans:
5.2L/5.9L V8 Pickups And Vans:
OLD INDEX: This is the old index (that I'm no longer adding tutorials to):
Here's a sample of the tutorials you'll find in the old index:
- How To Test The Starter Motor (Dodge 3.9L, 5.2L, 5.9L).
- How To Test The Ignition Coil -No Start Tests (Chrysler 3.9L, 5.2L, 5.9L).
- How To Test The MAP Sensor (P0107, P0108) (Dodge 3.9L, 5.2L, 5.9L).
- How To Test Engine Compression (Chrysler 3.9L, 5.2L, 5.9L).
- How To Test A No Start Condition (Dodge 3.9L, 5.2L, 5.9L).
If this info saved the day, buy me a beer!
