TEST 2: Making Sure The CKP Sensor Is Getting 5 Volts
One of the problems that can keep the CKP sensor from producing a signal is a lack of power.
So, in this test section, we're gonna' make sure that the orange (ORG) wire, of engine wiring harness connector, is providing the CKP sensor with 5 Volts DC.
We'll do a simple multimeter voltage test to find out if these 5 Volts are present in the ORG 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 orange (ORG) 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 ORG wire is providing 4.5 to 5 Volts DC. This is the correct test result.
The next step is to make sure that the CKP sensor is getting Ground on the BRN/YEL wire. Go to: TEST 3: Making Sure The CKP Sensor Is Getting Ground.
CASE 2: The ORG wire IS NOT providing 5 Volts DC. 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 ORG 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 CKP sensor test, we'll make sure that the crankshaft position sensor is getting Ground from the brown with yellow stripe (BRN/YEL) wire of the engine wiring harness connector.
To test for the presence of this Ground, we'll do a simple multimeter voltage test.
IMPORTANT: Be careful not to short this wire to battery voltage (12 Volts DC), 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 BRN/YEL wire.
- 6
Your multimeter should register 10 to 12 Volts DC if the BRN/YEL wire is providing Ground to the CKP sensor.
Let's interpret your test result:
CASE 1: The BRN/YEL wire is providing Ground. 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 BRN/YEL wire IS NOT providing Ground. 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 sensor is not receiving Ground. The most likely cause of this missing Ground is an open-circuit problem somewhere on the BRN/YEL 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!
