TEST 1: Testing The CKP Signal With A Multimeter
The crankshaft position sensor is located behind the engine (the side facing the vehicle's firewall) above the oil filter adapter. This type of crankshaft position sensor goes thru' the block itself and is held securely in place by a bolt.
You'll need to jack up the vehicle to gain access to the crankshaft position sensor. Be careful, think safety all of the time, take all precautions. Use a jack stand to hold the car up in the air, do not trust the jack! Wear safety glasses to protect your eyes from falling debris.
The very first thing you do, to start troubleshooting the crankshaft position sensor, is to verify that it's either generating a crankshaft position sensor signal or not. You'll use a multimeter for this and all parts of the crankshaft position sensor test.
NOTE: The crankshaft position sensor must remain connected to its electrical connector to read the CKP signal. To access the CKP signal, inside the wire, 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 here: Wire Piercing Probe.
Alright, this are the test steps:
- 1
Jack up the car or mini-van and place it on jack stands.
CAUTION: Set the parking brake and/or place wheel chocks behind the rear wheels to keep the vehicle from rolling back. - 2
Disconnect the ignition coil pack from its electrical connector. This is important! Do not proceed with the test without first unplugging the ignition coil pack.
- 3
Locate the CKP sensor's connector.
Remove some of the plastic wire loom protector and/or the black electrical tape that shields the three wires of the CKP sensor. Remove enough of this electrical tape insulation to gain comfortable access to the three wires it protects. - 4
Reconnect the crankshaft position sensor to its electrical connector now if it was necessary to unplug the connector from the crank (CKP) sensor to remove some of the black electrical tape insulation.
NOTE: The crankshaft position sensor must be connected to its electrical connector for this test to work. - 5
Place the multimeter in Volts DC mode.
- 6
Connect the red multimeter test lead to the wire identified with the number 1 in the photo above, of the three wire connector. This wire is the middle wire of the connector.
The number 1 is the signal wire that transmits the crankshaft position (CKP) sensor signal to the PCM. - 7
Connect the black multimeter test lead to a good Ground point on the engine or directly on the battery negative (-) terminal.
- 8
When everything is set up, turn the crankshaft pulley by hand in a clock-wise direction while you keep your eyes on the multimeter.
IMPORTANT: Do not use the starter motor to crank the engine, since this will defeat the accuracy of this test. - 9
The multimeter should register an ON/OFF voltage of 5 Volts DC as you manually turn the engine by hand.
ON is when the multimeter displays 5 Volts DC and OFF is 0.5 Volts DC.
The key to seeing this voltage change is to turn the crankshaft pulley slowly and steadily.
Alright, let's find out if you have a bad CKP sensor on your hands or not. Choose from the CASES below that best match your specific results:
CASE 1: The multimeter registered the ON/OFF 5 Volts DC as the crankshaft pulley was hand-turned. This result indicates that the CKP sensor is creating a good CKP signal and is working fine.
Now, if the crankshaft position sensor signal is present and yet your car does not start you'll need to make sure that there's no spark and no fuel injection since if either of these are present, the crankshaft position sensor is not the cause of your vehicle's no-start condition.
CASE 2: The multimeter DID NOT register the ON/OFF 5 Volts DC as the crankshaft pulley was hand-turned. This is not good. The sensor should have produced the indicated ON/OFF 5 Volt signal. But before we condemn the CKP sensor as bad, you need to verify that it's getting power and Ground. Go to: TEST 2: Making Sure The CKP Sensor Is Getting Power.
The next step is to check that the crankshaft position sensor is getting power. This comes in the form of either 5 Volts or 8 Volts, depending on how old your specific Chrysler (or Dodge or Plymouth or etc.) is. The PCM (Powertrain Control Module=Fuel Injection Computer) is the one that provides these 8 Volts to power the crankshaft position sensor.
TEST 2: Making Sure The CKP Sensor Is Getting Power
In this test step, you're going to verify that the crankshaft position sensor is getting power.
As mentioned earlier, this power comes in the form of 5 or 8 Volts from the PCM. Don't worry about what specific voltage your specific vehicle should output since it will be either one or the other.
IMPORTANT: You got to be very careful not to short this wire to Ground since you run the risk of damaging the PCM. Also, do not use a test light to verify this voltage, use a multimeter.
- 1
Place your multimeter in Volts DC mode.
- 2
Disconnect the crankshaft positions sensor from its electrical connector.
- 3
Gently probe the terminal that connects to the wire identified with the number 3 with the red multimeter test lead and an appropriate tool.
- 4
Ground the black multimeter test lead to a good Ground point on the engine or directly on the battery negative (-) terminal.
- 5
When everything is set up, have your helper turn the key to the On position but don't crank the engine.
- 6
Your multimeter should register 5 or 8 Volts DC.
OK, let's interpret the multimeter test results you just obtained. Choose from the CASES below that best match your specific results:
CASE 1: The multimeter registered 5 or 8 Volts DC when the key was turned On. This let's you know that the CKP sensor is being fed with power from the PCM.
There's still one more test to do, before we can condemn the crankshaft position sensor as bad, and that is to make sure that it's getting Ground. For this test go to: TEST 3: Making Sure The CKP Sensor Is Getting Ground.
CASE 2: The multimeter DID NOT register 5 or 8 Volts DC when the key was turned On. Recheck your connections and try the test again.
If the multimeter still does not register the indicated voltage, then this result lets you know that the reason there was no ON/OFF 5 Volt signal, registered in TEST 1, is because the crankshaft position (CKP) sensor is not getting power. You have now eliminated the crankshaft position sensor as the cause of the no-start condition.
Solving the issue that is causing these missing 5 or 8 Volts will solve the no-start condition of your Chrysler 2.0L/2.4L equipped car or mini-van.
