If the crankshaft position sensor is bad, then your 5.2L Jeep Grand Cherokee is not gonna' start.
The cool thing is that the crankshaft position (CKP) sensor, on the 1993-1995 5.2L V8 Jeep Grand Cherokee, can be tested with a multimeter.
In this tutorial I'll walk you thru' the 3 tests you need to perform to find out if it's bad (or not) in a step-by-step way.
Contents of this tutorial:
- Symptoms Of A Bad Crankshaft Position (CKP) Sensor.
- Circuit Descriptions Of The Crankshaft Position Sensor.
- TEST 1: Testing The Crankshaft Position Signal.
- TEST 2: Making Sure The CKP Sensor Has Power.
- TEST 3: Making Sure The CKP Sensor Has Ground.
- Where To Buy The Crankshaft Position Sensor.
- More 5.2L Jeep Grand Cherokee Tutorials.
APPLIES TO: This tutorial applies to the following vehicles since they use the exact same crankshaft position (CKP) sensor:
- 5.2L V8 Jeep Grand Cherokee: 1993, 1994, 1995, 1996.
IGNITION COIL TEST: The following tutorial will help you test the ignition coil: How To Test The Ignition System (1993-1998 5.2L Grand Cherokee).
WIRING DIAGRAM: You can find the ignition system wiring diagrams here:
- Ignition System Wiring Diagram (1993-1995 5.2L Jeep Grand Cherokee).
- Ignition System Wiring Diagram (1996-1998 5.2L Jeep Grand Cherokee).
Symptoms Of A Bad Crankshaft Position (CKP) Sensor
Over the years that I've been working as an automotive technician I've noticed that the crankshaft position sensor will fail in one of two ways. It will either fail completely and the engine will crank but not start due to a lack of spark.
Or the crankshaft position sensor will fail intermittently. In this type of failure, the sensor works fine most of the time but every now and then it does not. And when it stops working, the engine will not start or if it's running, the engine will stall (die).
Although the fuel injection computer monitors the CKP signal all of the time (the engine is cranking or running) and is designed to set a trouble code when it doesn't see it (like when the sensor fails), it doesn't always do so. But when it does set a trouble code, you'll see:
- Code 11: No Crankshaft Reference Signal At PCM (1994-1995 OBD I system).
- P0320: No Crank Reference Signal At PCM (1996 OBD II system).
If you suspect that the crankshaft position sensor is behind a no-start problem, it's a good idea to check for a CKP sensor trouble code.
Circuit Descriptions Of The Crankshaft Position Sensor
As you can see in the photo above, the crankshaft position sensor is a 3-wire sensor. Since it's a Hall Effect sensor, it needs power and Ground to generate its crankshaft position signal.
Power is in the form of 8 Volts DC (1994-1995 5.2L V8 Jeep Grand Cherokee) or 5 Volts DC (1996 5.2L V8 Jeep Grand Cherokee). This voltage is provided by your 5.2L V8 Jeep Grand Cherokee's fuel injection computer.
The Ground that the crankshaft position sensor needs is also provided by the fuel injection computer.
The connector on the sensor itself has male spade terminals. The connector on the engine wiring harness has female terminals.
Since we'll be testing for the presence of the CKP signal, 8 Volts (or 5 Volts), and Ground, the following tables have a brief job description of each of the 3 wires:
| 1994-1995 Crankshaft Position Sensor Connector | ||
|---|---|---|
| Pin | Wire Color | Description |
| 1 | White with black stripe (WHT/BLK) | Power (8 Volts DC) |
| 2 | Black with light blue stripe (BLK/LT BLU) | Sensor Ground |
| 3 | Red with light green stripe (RED/LT GRN) | CKP Signal |
| 1996 Crankshaft Position Sensor Connector | ||
|---|---|---|
| Pin | Wire Color | Description |
| 1 | White with black stripe (WHT/BLK) | Power (5 Volts DC) |
| 2 | Black with light blue stripe (BLK/LT BLU) | Sensor Ground |
| 3 | Red with light green stripe (RED/LT GRN) | CKP Signal |
When the engine starts to crank, the crankshaft position sensor produces an ON/OFF voltage signal (once it gets power and Ground).
To be a bit more specific ON is when the CKP sensor produces a voltage signal of 5 Volts. And OFF is when the CKP sensor prodcues a voltage signal of 0 Volts.
This ON/OFF voltage is only produced when the engine is cranking or running and the crankshaft position sensor is running.
Thankfully, this ON/OFF voltage signal can be tested with a simple multimeter. The key to testing the CKP voltage signal is to turn the engine by hand. In other words you can't use the starter motor.
TEST 1: Testing The Crankshaft Position Signal
When the crankshaft position sensor fails, it'll stay stuck producing a single voltage value as the engine is cranking.
In other words, the crankshaft position sensor does not produce an ON/OFF voltage signal as the engine turns.
To check for the ON/OFF signal voltage, that the CKP sensor produces, we're gonna' connect the multimeter to the red with light green (RED/LT GRN) wire of its 3-wire connector.
The RED/LT GRN wire is the one labeled with the number 3 in the photo of the crankshaft position sensor's connector above.
IMPORTANT: The crankshaft position sensor must be connected to its engine harness connector for this test to work. You'll need to connect your multimeter test lead to a back probe or a wire piercing probe to read the crank signal. You can see an example of a wire piercing probe here: Wire Piercing Probe Review (Power Probe PWPPPPP01).
NOTE: Don't have a multimeter or need to upgrade yours? Check out my recommendation: Buying A Digital Multimeter For Automotive Diagnostic Testing (at: easyautodiagnostics.com).
These are the test steps:
- 1
Place your multimeter in Volts DC mode.
- 2
Disconnect the ignition coil from its electrical connector. This is an important safety precaution!
- 3
With the red multimeter test lead, probe the red with light green stripe (RED/LT GRN) wire of the crank sensor connector.
NOTE: The crankshaft position sensor must remain connected to its engine wiring harness connector to be able to read its signal. - 4
Connect the black multimeter test lead directly on the battery negative (-) terminal.
- 5
Turn the ignition key to the ON position and turn the engine by hand using the 1/2" ratchet wrench and appropriate socket on the crankshaft pulley. For the accuracy of the test, do not use the starter motor.
- 6
Your multimeter will read an ON/OFF voltage of 5 Volts and 0 Volts (if the crankshaft position sensor is functioning correctly).
ON is when the multimeter reads 4-5 Volts DC and OFF is when it reads 0 Volts DC.
Let's interpret your CKP signal test result:
CASE 1: The ON/OFF DC voltage signal is present in the RED/LT GRN wire. This is the correct and expected test result.
This test result tells you that the crankshaft position sensor is functioning correctly and is not behind your 5.2L V8 Jeep Grand Cherokee's no-start problem.
CASE 2: The ON/OFF DC voltage signal IS NOT present in the RED/LT GRN wire. This test result usually means that the crankshaft position sensor is defective.
Before you replace it, make sure it's getting power and Ground. For the next test go to: TEST 2: Making Sure The CKP Sensor Has Power.