TEST 4: Verifying Coil Pack Is Getting Power
In this test section, you'll check that the ignition coil pack is getting power.
You can use a multimeter or a test light to test the power (12 Volt) Circuit of the Chrysler coil pack.
The coil pack can be connected or not to its connector. The following test steps assume that you'll test the power circuit with a multimeter and with the connector connected to the ignition coil pack.
- 1
The 4 wires in the ignition coil pack's connector are usually sheathed in black electrical tape that has probably turned plastic hard, remove enough of this electrical tape to expose the three wires for testing.
- 2
With the ignition coil connected to its connector.
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Put the multimeter in Volts DC mode (don't have a digital multimeter? Need to buy one? Click here to see my recommendations: Buying A Digital Multimeter For Automotive Diagnostic Testing).
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Probe the circuit labeled with the number 3 (see photo in image viewer) with the red multimeter test lead (using an appropriate tool to pierce the wire).
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With the black multimeter test lead probe the battery negative (-) terminal.
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Have your helper turn the key to the ON position and then crank the engine. Continuous voltage is only provided when the engine is being cranked.
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You should see 10-12 Volts on your multimeter, or if you're using a test light, the test light should light up.
Let's take a look at what your test results mean:
CASE 1: The multimeter registered 10 to 12 Volts DC. This is the correct test result.
The next step is verify that the Switching signals are present, go to: TEST 5: Switching Signal Cylinders 1/4, then TEST 6: Switching Signal Cylinders 2/5, and then TEST 7: Switching Signal Cylinders 3/6.
If the all three Switching signals are not present (after testing them in TEST 5, TEST 6, and TEST 7), the most likely cause will be that there's an open-circuit problem in the engine wiring harness or a bad connector somewhere in the engine harness.
Troubleshooting the cause of these missing Switching signals is beyond the scope of this article, but you have at least eliminated the coil pack as the cause of the 'no-spark no-start' problem.
CASE 2: The multimeter DID NOT register 10 to 12 Volts DC. Re-check all of your connections and retest.
If still no voltage is present, this result exonerates the coil pack. Repairing the cause of this missing voltage will solve the 'no-spark no-start' condition of your Chrysler (or Dodge or Plymouth) mini-van. The most common reasons for no power are:
- The Crankshaft Position (CKP) sensor is bad. If the CKP sensor is bad, the PCM will not power up the Auto Shut Down (ASD) Relay, which in turn will not power up the ignition coil pack or any other ignition system or fuel system component.
- A bad Auto Shut Down (ASD) Relay.
- A blown fuse.
TEST 5: Switching Signal Cylinders 1/4
Testing for the Switching signal, of the ignition coil (within the coil pack) that feeds cylinders 1 and 4, is a very simple and straightforward process.
You'll need to use an LED light and the ignition coil pack has to be connected to its connector.
You can see an example of the LED light here: The LED Light Test Tool And How To Make One.
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With an appropriate tool, connect the black lead of the LED light to the wire identified with the number 1 in the image viewer.
This is the circuit that feeds the Switching signal to the ignition coil (within the coil pack) that feeds spark to cylinders 1 and 4 simultaneously. - 2
Connect the red lead of the LED light to the battery positive (+) terminal.
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Have your helper crank the car (the car may start so be careful).
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If the car started, have your helper turn it off.
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If the Switching signal is present, the LED light will flash ON and OFF the whole time the engine was cranking and during the time it was running.
Let's take a look at what your test results mean:
CASE 1: The LED light flashed ON and OFF the whole time the engine was cranking or running. This tells you that the PCM is providing the Switching signal and the circuit is OK. This result confirms that the ignition coil pack is bad, replace it.
CASE 2: The LED light DID NOT flash ON and OFF the whole time the engine was cranking or running. This tells you that the Switching signal is not present.
The most likely cause of this missing signal is either an open-circuit problem in the circuit between the connector and the PCM or the PCM is fried (altho' a fried PCM is rare). With this result you have eliminated the coil pack as the source of the misfire condition or no-spark condition.
