TEST 1: Testing The CKP Signal With A Multimeter
As mentioned before, the CKP sensor produces an ON/OFF voltage as the engine turns.
ON is when the signal is 5 Volts and OFF is when its 0 Volts.
When the CKP sensor fails, it'll stop producing this ON/OFF voltage signal and stay stuck producing one voltage value as the engine turns.
To check the CKP sensor's ON/OFF voltage signal, we're going to connect a multimeter to its signal wire.
Then we'll rotate the engine by hand and see if the ON/OFF voltage is present.
NOTE: The crankshaft position sensor must remain connected to its electrical connector to be able to read 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, these are the test steps:
Raise the front of the 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.
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.
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.
Reconnect the crankshaft position sensor to its electrical connector now if you unplugged it in the previous test step.
NOTE: The crankshaft position sensor must be connected to its electrical connector for this test to work.
Place the multimeter in Volts DC mode.
Connect the red multimeter test lead to the wire identified with the number 1 in the photo above, of the three wire connector.
The number 1 is the signal wire that transmits the crankshaft position (CKP) sensor signal to the PCM.
Connect the black multimeter test lead to a good Ground point on the engine or directly on the battery negative (-) terminal.
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.
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 analyze your test results:
CASE 1: The ON/OFF voltage signal is present. This is the correct and expected test result and it lets you know that the crankshaft position sensor is OK.
Now if your car does not start, you can conclude that the crankshaft position sensor is not the component behind the problem.
CASE 2: The ON/OFF voltage signal IS NOT present. This test result confirms that the engine is not starting because the crankshaft position sensor is not producing a CKP signal.
The next step is to check that the crankshaft position sensor is getting power. Go to: TEST 2: Making Sure The CKP Sensor Is Getting Power.
TEST 2: Making Sure The CKP Sensor Is Getting Power
The crankshaft position sensor receives 8 Volts DC from your mini-van's fuel injection computer.
The wire that supplies power to the CKP sensor is the wire labeled with the number 3 in the photo above.
The following table will help you identify the CKP sensor's power wire on your specific vehicle:
|2.4L Chrysler Voyager: 2001, 2002||brown with pink stripe (BRN/PNK)|
|2.4L Dodge Caravan: 1996, 1997, 1998, 1999, 2000||orange (ORG)|
|2.4L Dodge Caravan: 2001, 2002||brown with pink stripe (BRN/PNK)|
|2.4L Dodge Grand Caravan: 1996, 1997||orange (ORG)|
|2.4L Plymouth Grand Voyager: 1996, 1997||orange (ORG)|
|2.4L Plymouth Voyager: 1996, 1997, 1998, 1999, 2000||orange (ORG)|
These are the test steps:
Place your multimeter in Volts DC mode.
Disconnect the crankshaft position sensor from its electrical connector.
Gently probe the terminal that connects to the wire identified with the number 3 with the red multimeter test lead and an appropriate tool.
Ground the black multimeter test lead to a good Ground point on the engine or directly on the battery negative (-) terminal.
When everything is set up, have your helper turn the key to the On position but don't crank the engine.
Your multimeter should register 7 to 8 Volts DC.
OK, let's interpret your test results:
CASE 1: The CKP sensor is receiving 8 Volts DC. This is the correct test result.
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 CKP sensor IS NOT receiving 8 Volts DC. Without these 8 Volts, the CKP sensor will not produce an ON/OFF 5 Volt signal.
The most likely cause of these missing 8 Volts DC is an open-circuit problem in the wire between the CKP sensor's connector and the fuel injection computer's connector.
Although it's beyond the scope of this tutorial to troubleshoot these missing 8 Volts, your next step is to find out why they're missing and resolve the issue.