TEST 2: Making Sure The CMP Sensor Has Power
To produce its ON/OFF voltage signal, the camshaft position sensor needs 8 Volts DC (1993-1995 Grand Cherokee) or 5 Volts DC (1996-1997 Grand Cherokee). These 8 Volts or 5 Volts are provided by your 5.2L Jeep Grand Cherokee's fuel injection computer.
The wire that carries these 8 Volts (or 5 Volts) from the computer to the camshaft position sensor is the white with black stripe (WHT/BLK) wire of the sensor's 3-wire connector.
The WHT/BLK wire is labeled with the number 1
If the CMP sensor is getting 8 Volts (or 5 Volts) from the WHT/BLK, then the next step is to go to TEST 3 and make sure that the camshaft position sensor is getting Ground.
NOTE: Avoid probing the front of the female terminal with your multimeter test lead or you run the risk of damaging the terminal. Use a back-probe on the back of the connector or use a wire-piercing probe on the wire.
These are the test steps:
- 1
Disconnect the CMP sensor from its connector.
- 2
Place your multimeter in Volts DC mode.
- 3
Turn the key on but don't crank or start the engine.
- 4
Connect the red multimeter test lead (using the appropriate tool) to the WHT/BLK wire identified with the number 1 in the photo above.
NOTE: This test is done on the connector that has female terminals. - 5
Connect the black multimeter test lead to the negative (-) battery terminal.
- 6
Your multimeter should read 7.5 to 8 Volts (1993-1995 Grand Cherokee) or 4.5 to 5 Volts (1996-1997 Grand Cherokee)
Let's analyze your test result:
CASE 1: 8 Volts (or 5 Volts) are present in the WHT/BLK wire. This is the correct and expected test result.
The next and last test is to make sure that Ground is present in the BLK/LT BLU wire of the connector. For this test go to: TEST 3: Making Sure The CMP Sensor Has Ground.
CASE 2: 8 Volts (or 5 Volts) ARE NOT present in the WHT/BLK wire. Without this voltage the camshaft position sensor will not produce a CMP voltage signal.
A lack of 5 Volts is usually due to an open-circuit problem in the ORG or WHT/BLK wire between the CMP sensor's connector and the fuel injection computer's connector.
Although it's beyond the scope of this tutorial to check for this missing power, your next step is to find out why it's missing and restore it.
TEST 3: Making Sure The CMP Sensor Has Ground
So far your CMP sensor tests have verified that:
- The camshaft position sensor is not producing an ON/OFF voltage signal (TEST 1).
- The WHT/BLK wire is feeding the camshaft position sensor with 8 Volts DC (or 5 Volts DC).
In this last test section we'll check the black with light blue stripe (BLK/LT BLU) wire to see if it's providing Ground to the CMP sensor.
I've labeled the BLK/LT BLU wire with the number 2 in the photo above.
IMPORTANT: Be careful and don't short the BLK/LT BLU wire to battery power (12 Volts) or you'll fry the fuel injection computer. The multimeter voltage test I'm suggesting below (for testing the presence of Ground in this wire) is a safe and accurate test.
NOTE: Avoid probing the front of the female terminal with your multimeter test lead or you run the risk of damaging the terminal. Use a back-probe on the back of the connector or use a wire-piercing probe on the wire.
These are the test steps:
- 1
Disconnect the CMP sensor from its connector.
- 2
Place your multimeter in Volts DC mode.
- 3
Turn the key on but don't crank or start the engine.
- 4
Connect the black multimeter test lead (using the appropriate tool) to the BLK/LT BLU wire identified with the number 2 in the photo above.
NOTE: This test is done on the connector that has female terminals. - 5
Connect the red multimeter test lead to the positive (+) battery terminal.
- 6
Your multimeter should read 10 to 12 Volts DC if the BLK/LT BLU wire is providing Ground.
Let's take a look at what your test results mean:
CASE 1: The BLK/LT BLU wire is providing Ground. This is the correct test result and let's you know that the camshaft position sensor is getting Ground.
You can correctly conclude that the camshaft position sensor is bad and needs to be replaced if you have:
- Confirmed that the camshaft position sensor IS NOT creating an ON/OFF voltage signal (TEST 1).
- Confirmed that the WHT/BLK wire is providing the CMP sensor with 8 or 5 Volts DC (TEST 2).
- Confirmed that the BLK/LT BLU wire is providing the CMP sensor with Ground.
CASE 2: The BLK/LT BLU wire IS NOT providing Ground. Without Ground, the camshaft position sensor will not produce an ON/OFF voltage signal.
The most likely cause of this missing Ground is an open-circuit problem in the BLK/LT BLU wire between the CMP sensor's connector and the fuel injection computer's connector.
Although it's beyond the scope of this tutorial to check for this missing Ground, your next step is to find out why it's missing and restore it.
Where To Buy The Camshaft Position Sensor
The camshaft position sensor (distributor pickup coil) is not an expensive component. Check out the following links and comparison shop. I think you'll save a few bucks:
More 5.2L Jeep Grand Cherokee Tutorials
You can find a complete list of 5.2L Jeep Grand Cherokee tutorials in this index:
Here's a small sample of the tutorials you'll find in the index:
- How To Do An Engine Compression Test (1993-1998 5.2L Jeep Grand Cherokee).
- How To Test A Blown Head Gasket (1993-1998 5.2L Grand Cherokee).
- How To Test The MAP Sensor (1993-1996 5.2L Grand Cherokee).
- Ignition System Wiring Diagram (1996-1998 5.2L Jeep Grand Cherokee).
If this info saved the day, buy me a beer!
