Testing the crankshaft position (CKP) sensor, on your 1996 4.0L Jeep Cherokee, is not difficult.
In this tutorial, I'll show you how to do it with step-by-step test instructions. You'll be able to easily find out if it's bad or not.
Contents of this tutorial:
- Important Tips And Suggestions.
- Where To Buy The Crankshaft Position Sensor And Save.
- Circuit Descriptions Of The Crankshaft Position Sensor.
- TEST 1: Testing The CKP Signal With A Multimeter.
- TEST 2: Making Sure The CKP Sensor Is Getting 5 Volts.
- TEST 3: Making Sure The CKP Sensor Is Getting Ground.
- More 4.0L Jeep Cherokee Tutorials.
You can find this tutorial in Spanish here: Cómo Probar El Sensor CKP (1996 4.0L Jeep Cherokee) (at: autotecnico-online.com).
APPLIES TO: This tutorial, on testing the CKP sensor, applies to the following vehicles:
- 1996 4.0L Jeep Cherokee.
RELATED WIRING DIAGRAMS:
- How To Test The Crankshaft Position Sensor (1993-1995 4.0L Jeep Cherokee).
- How To Test The Crankshaft Position Sensor (1997-1998 4.0L Jeep Cherokee).
Important Tips And Suggestions
TIP 1: The CKP sensor test is an on-car test -you should not remove it to test it.
TIP 2: You'll need to turn the engine manually with a socket and ratchet on the crankshaft pulley to get the correct test result -don't use the starter motor.
TIP 3: Test the spark plug wires for spark before testing the CKP sensor (if you haven't already).
If any of the spark plug wires are sparking, then the CKP sensor is OK and doing its job.
TIP 4: Take all necessary safety precautions. Think safety all of the time.
Where To Buy The Crankshaft Position Sensor And Save
The following links will help you to comparison shop for the CKP sensor on the 1996 4.0L Jeep Cherokee:
Not sure if the above crankshaft position sensor fits your particular 1996 4.0L Jeep Cherokee? Don't worry, once you get to the site, they'll make sure it fits by asking you the particulars of your vehicle. If it doesn't fit, they'll find you the right one.
Circuit Descriptions Of The Crankshaft Position Sensor
Here's a brief description of each one of the 3 wires of the engine wiring harness connector:
|1||Violet With White Stripe (VIO/WHT)||5 Volts|
|2||Black With Light Blue Stripe (BLK/LT BLU)||Sensor Ground|
|3||Gray With Black Stripe (GRY/BLK)||CKP Signal|
You can consult the following ignition system wiring diagram for more info:
TEST 1: Testing The CKP Signal With A Multimeter
For our first test, we're gonna' make sure that the CKP sensor is producing a signal.
To accomplish this, we're gonna' connect the multimeter to the gray with black stripe (GRY/BLK) wire of the CKP sensor's engine wiring harness connector.
If the CKP sensor is OK, then you should see your multimeter register an ON/OFF voltage signal as the engine is manually turned.
NOTE: The CKP sensor must remain connected to its electrical connector for this test to work. You'll need to use a back probe on the connector or a wire piercing probe on the wire. You can see an example of this tool (and where to buy it) here: Wire Piercing Probe Review (Power Probe PWPPPPP01).
OK, let's get started:
Disable the ignition system by disconnecting the ignition coil.
This step is important do not proceed to the next step until you've done this.
Disable all of the fuel injectors.
This step is important also, since this will prevent the PCM from injecting fuel into the engine cylinders (if the CKP sensor is OK).
Locate the CKP sensor's connector. This connector will be on the intake manifold side of the engine.
Place the multimeter in Volts DC mode.
Connect the red multimeter test lead to the GRY/BLK wire of the engine wiring harness connector with an appropriate tool.
NOTE: The CKP sensor must remain connected to its connector. Use a back probe on the connector or a wire piercing probe on the wire to access the signal inside the GRY/BLK wire.
Connect the black multimeter test lead to battery negative (-) terminal.
Turn the key to the ON position (but don't crank the engine). This will power up the crankshaft position sensor.
Have a helper turn the crankshaft pulley by hand in a clock-wise direction.
Your job is to keep your eyes glued on the multimeter's display.
NOTE: Do not use the starter motor to crank the engine, since this will defeat the accuracy of this test.
Your multimeter should show an ON/OFF voltage of 5 Volts/0 Volts DC as the crankshaft pulley is turned by hand.
OFF is when your multimeter reads 0 Volts and ON is when it reads 5 Volts. The key to seeing this voltage change is to turn the crankshaft pulley slowly and steadily.
Alright, let's interpret your test results:
CASE 1: The multimeter registered the ON/OFF signal voltage. This is the correct and expected test result and it confirms that the crankshaft position sensor is working correctly.
CASE 2: The multimeter DID NOT register the ON/OFF signal voltage. In most cases, you can conclude the CKP sensor is fried and that it needs to be replaced. But (yeah, I know) not always.
Therefore, the next step is to check that the crankshaft position sensor is getting power. This comes in the form of 5 Volts and from your Jeep Cherokee's fuel injection computer. For this test go to: TEST 2: Making Sure The CKP Sensor Is Getting 5 Volts.