TEST 2: Verifying The Crank Sensor Is Getting Power
Depending on what specific 3.9L, 5.2L or 5.9L Dodge pick up (van or SUV) you drive, the crank sensor will get power on a PPL/WHT (purple/white) or an ORG (orange) wire of its harness connector.
What you'll do in this test section is see if power, in the form of 5 Volts DC, is present in this PPL/WHT (or ORG) wire.
Like the previous test, this is also a simple multimeter test done with the multimeter in Volts DC mode.
Depending on your specific Dodge Ram pickup, van or SUV, 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.
NOTE: This test is done with the engine off. So, as a safety precaution don't crank or start the engine to check for this voltage.
This is what you need to do:
- 1
Disconnect the CKP sensor from its engine wiring harness connector.
- 2
Ground the black lead of the multimeter directly on the battery negative (-) terminal.
- 3
Set your multimeter to Volts DC mode.
- 4
Probe the front of the terminal that connects to the PPL/WHT (or ORG) wire of the crank sensor's harness connector with the red multimeter test lead.
- 5
Turn the key to the ON position, no need to crank the engine with the starter motor.
- 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: The multimeter registered 4.5 to 5 Volts DC when the key was turned On. This is the correct and expected test result and confirms that the crank sensor is getting power from the PCM.
The next step is to make sure that the crank sensor is getting Ground. For this test go to: TEST 3: Verifying The Crank Sensor Is Getting Ground.
CASE 2: The multimeter DID NOT register 4.5 to 5 Volts DC when the key was turned On. Double check that you're testing the correct wire and repeat the test.
If the multimeter still does not show 5 Volts, then this test result confirms 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
Up this point, you have checked and verified that the crank sensor:
One: Is not producing an ON/OFF voltage signal (TEST 1).
Two: Verified that the PPL/WHT wire of the harness connector is feeding the crank sensor with 5 Volts DC (TEST 2).
The last test, to find out if the crank sensor is bad, is to check that it's getting Ground with a simple multimeter voltage test.
IMPORTANT: The crank sensor gets this Ground from the PCM and not chassis Ground. Be careful and don't short this wire to battery voltage or you'll fry the PCM.
Alright, this is what you'll need to do:
- 1
Disconnect the CKP sensor from its engine wiring harness connector.
- 2
Ground the red lead of the multimeter directly on the battery positive (+) terminal.
- 3
Set your multimeter to Volts DC mode.
- 4
Probe the front of the female terminal that connects to the BLK/LT BLU wire with the black multimeter test lead.
NOTE: Remember, you're testing the engine wiring harness connector with female terminals. - 5
Turn the key to the ON position, no need to crank the engine with the starter motor.
- 6
Your multimeter should register 10 to 12 Volts DC if Ground is present in the BLK/LT BLU wire.
Let's interpret your specific test results:
CASE 1: The multimeter registered 10 to 12 Volts DC when the key was turned On. This test result tells you that the BLK/LT BLU wire is feeding the crank sensor with Ground. Taking into account the results from the previous 2 tests (and this one), you can conclude that the crank sensor is bad and needs to be replaced.
Here's why: A good working crank sensor, when it receives power and Ground and the engine is cranking, will generate an ON/OFF 5 Volt signal. Now, in your particular case:
- In TEST 1 you verified the crank sensor is not creating its ON/OFF 5 Volt Signal.
- In TEST 2 you confirmed that it's being fed with power (5 Volts) and in this test step, you have verified that it's getting a good Ground.
- Therefore the crank sensor is bad and replacing the crank sensor will solve the cranks but does not start issue.
CASE 2: The multimeter DID NOT register 10 to 12 Volts DC when the key was turned On. 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!
