TEST 2: Making Sure The CKP Sensor Is Getting 5 Volts
The wire that supplies 5 Volts to the CKP sensor is the violet with white stripe (VIO/WHT) wire of engine wiring harness connector.
In the photo above, I've labeled the VIO/WHT wire with the number 1.
We'll do a simple multimeter voltage test to find out if these 5 Volts are present in the VIO/WHT wire or not.
Let's get testing:
- 1
Place your multimeter in Volts DC mode.
- 2
Disconnect the crankshaft position sensor from its connector.
- 3
Connect the black multimeter test lead to the battery negative (-) terminal.
- 4
Turn the key to the ON position but don't crank the engine.
- 5
With the red multimeter test lead, gently probe the terminal that connects to the violet with white stripe (VIO/WHT) wire of the engine wiring harness connector.
- 6
Your multimeter should register 4.5 to 5 Volts DC.
OK, let's analyze your test result:
CASE 1: The multimeter registered 4.5 to 5 Volts DC. This is the correct test result.
Now that you've confirmed that the CKP sensor is getting 5 Volts, your next step is to make sure it's getting Ground. Go to: TEST 3: Making Sure The CKP Sensor Is Getting Ground.
CASE 2: The multimeter DID NOT register the indicated voltage. Without these 5 Volts, the CKP sensor will not produce a CKP signal.
The most likely cause of this missing voltage is an open-circuit problem somewhere on the VIO/WHT wire between the CKP sensor connector and the fuel injection computer's connector.
TEST 3: Making Sure The CKP Sensor Is Getting Ground
For the 3rd and final test, we'll make sure that the crankshaft position sensor is getting Ground.
The wire that feeds the CKP sensor with Ground is the black with light blue stripe (BLK/LT BLU) wire of the engine wiring harness connector.
In the photo above, I've labeled the BLK/LT BLU wire with the number 2.
IMPORTANT: You got to be very careful not to short this wire to battery voltage, or you run the risk of damaging the fuel injection computer. The multimeter voltage test I'm suggesting in the test instructions is a safe way to test for the presence of Ground in the wire.
Alright, this is what you'll need to do:
- 1
Place your multimeter in Volts DC mode.
- 2
Disconnect the crankshaft position sensor from its connector.
- 3
Connect the red multimeter test lead to the battery positive (-) terminal.
- 4
Have you helper turn the key to the ON position but don't crank the engine.
- 5
With the black multimeter test lead, gently probe the female terminal that connects to the BLK/LT BLU wire.
- 6
Your multimeter should register 10 to 12 Volts DC.
Let's interpret your test result:
CASE 1: The multimeter registered 10 to 12 Volts DC. This is the correct and expected test result and it means that the CKP sensor is getting Ground.
You can conclude that the crankshaft position (CKP) sensor is bad and needs to be replaced if you have:
- Confirmed that the CKP sensor is not creating its ON/OFF voltage signal (TEST 1).
- Confirmed that the CKP sensor is being fed with 5 Volts (TEST 2).
- Confirmed that the CKP sensor getting Ground (this test section).
CASE 2: The multimeter DID NOT register 10 to 12 Volts DC. Recheck your connections and try the test again.
If the multimeter still does not register 10 to 12 Volts, then this result lets you know that the CKP is not receiving Ground. The most likely cause of this missing Ground is an open-circuit problem somewhere on the BLK/LT BLU wire.
More 4.0L Jeep Cherokee Tutorials
You can find a complete list of diagnostic tutorials and wiring diagrams for the 4.0L Jeep Cherokee here:
Here's a sample of the tutorials you'll find in the index:
- Ignition System Wiring Diagram (1993-1995 4.0L Jeep Cherokee)
- How To Test For A Blown Head Gasket (1993-2001 4.0L Jeep Cherokee)
- How To Test The Crankshaft Position Sensor (1993-1995 4.0L Jeep Cherokee)
- How To Do An Engine Compression Test (1993-2001 4.0L Jeep Cherokee)
If this info saved the day, buy me a beer!
