CKP TEST 2: Making Sure The CKP Sensor Is Getting Power
In this test step, you're gonna' verify that the crank sensor is getting power.
As mentioned earlier, this power can come in the form of either 8 Volts or 5 Volts (depending on what year your specific vehicle is). Don't worry about what specific voltage your specific vehicle should output since it will be either one or the other.
IMPORTANT: Take care not to short this wire to power (12 Volts) or you'll fry the PCM, since it's the PCM that provides this Ground internally.
- 1
Place your multimeter in Volts DC mode.
- 2
Probe the wire identified with the number 3 in the image above, with red multimeter test lead.
If you probe the front of the connector, be careful not to damage the female terminal. - 2
Connect the black multimeter test lead to the battery negative (-) terminal or a good Ground point on the engine.
- 3
When everything is set up, have your helper turn the key to the On position. Don't crank the engine.
- 4
If all is good with this circuit, your multimeter should register 5 or 8 Volts.
OK, let's interpret the multimeter test results you just obtained:
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 (5 or 8 Volts) from the PCM. There is still one more test to do, before we can condemn the crank sensor as bad. Go to: CKP 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 8 Volts, 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 crank 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 3.0L, 3.3L, 3.8L Chrysler equipped car or mini-van.
CKP TEST 3: Making Sure The CKP Sensor Is Getting Ground
The crankshaft position sensor also needs a Ground to function and create a crank signal.
So, in this test step, you're going to verify that the crankshaft position sensor is getting Ground. As mentioned earlier, the Ground path is completed inside the PCM.
IMPORTANT: You got to be very careful not to short this wire to battery voltage, or you run the risk of damaging the PCM. Also, do not use a test light to verify this voltage. Use a multimeter.
OK, this is what you need to do:
- 1
Place your multimeter still in Volts DC mode.
- 2
Probe the wire identified with the number 2 in the image above, with black multimeter test lead.
If you probe the front of the connector, be careful not to damage the female terminal. - 2
Connect the red multimeter test lead to the battery positive (+) terminal.
- 3
When everything is set up, have your helper turn the key to the On position. Don't crank the engine.
- 4
Your multimeter should register battery voltage (10 to 12 Volts).
Let's examine your test result:
CASE 1: The multimeter registered 12 Volts DC when the key was turned On. This is the correct test result and it confirms that the CKP sensor is getting a good Ground.
This results confirms that the crankshaft position (CKP) sensor is bad and that it needs to be replace only if you have:
- Confirmed that the CKP sensor is not producing an ON/OFF voltage signal as you turn manually turn the engine (TEST 1).
- Confirmed that the CKP sensor is receiving power (TEST 2).
- Confirmed that the CKP sensor is getting Ground (this test section)
Here's why: A good working CKP sensor, when it receives power and Ground and the engine is cranking, will generate an ON/OFF 5 Volt signal. Now, in your particular case, in TEST 1 you verified the CKP sensor is not creating its ON/OFF 5 Volt signal. In TEST 2 you confirmed that it's being fed with power (5 or 8 Volts) and in this test step, you have verified that it's getting a good Ground, therefore the CKP sensor is bad. Replace the CKP sensor.
If you'd like to save some bucks on the CKP sensor, check out my recommendations here: Where To Buy The CKP Sensor And Save.
CASE 2: The multimeter DID NOT register 12 Volts DC when the key was turned On. Recheck your connections and try the test again.
If the multimeter still does not register 10 to 12 Volts, then this result lets you know that the CKP does not have a good sensor Ground. You have now eliminated the crankshaft position (CKP) sensor as the cause of the no-start condition, since without this Ground, the CKP sensor will not work.
