How To Test The COP Coils (Chrysler 3.2L, 3.5L)

Testing and troubleshooting an ignition coil on your Chrysler or Dodge or Plymouth 3.2L V6 (or 3.5L V6) can be accomplished in three easy steps. Best of all, no scan tool is required. This article will show you how to diagnose and troubleshoot a bad ignition coil with step by step tests.

This article covers quite a few Chrysler and Dodge models (with either the 3.2L or 3.5L V6). If you need to verify if your vehicle is covered, there's a complete list, of Chrysler, Dodge, and Plymouth vehicles this info applies to, at the bottom of this page.

Symptoms Of A Bad Ignition Coil

Besides the check engine light (CEL) being lit on your Chrysler (or Dodge or Plymouth), your vehicle may experience one or several of the following:

1. Misfire codes that light up the check engine light (CEL) on your instrument cluster.
   • P0300, P0301, P0302, P0303, P0304, P0305, P0306
2. Engine misfire that DOES NOT light up the check engine light (CEL).
3. Smell of unburned gasoline coming out of the tailpipe.
4. Rotten egg smell coming out of the tailpipe. This is due to the unburned gasoline from the misfiring cylinder over loading the catalytic converter.
5. Really bad gas mileage.
6. Lack of power as you accelerate the vehicle down the road.

What Tools Do I Need?

To test the Chrysler (Dodge and Plymouth) 3.2L and 3.5L C.O.P. ignition coils, you don't need an automotive diagnostic scan tool (commonly known as a scanner or scan tool). You do need a few basic tools and they are:

1. An HEI spark tester
   • This inexpensive spark tester is a MUST have tool to correctly diagnose the Coil-On-Plug ignition coils on your Chrysler vehicle with the info and tests in this article without this tool.
   Don't use a regular spark plug instead of a spark tester.
2. Battery jump start cables.
3. A digital multimeter or a test light.
4. A helper.
   • You'll need someone to help you crank the engine while you perform the tests in the engine compartment.
5. A Repair manual.
   • For whatever remove and replace info you'll need that is not covered by this article.

Circuit Descriptions: Ignition Coil Connector

All of the circuits can be tested without having to unplug the Coil-On-Plug ignition coil on your Chrysler vehicle. What will make this possible is if you use a wire-piercing probe to attach to your multimeter leads (if you want to see what this tool looks like, click here: Wire Piercing Probe). Now, if you decide to test the front of the ignition coil connector, you have to be very careful not to damage the female terminals or you'll have a major headache on your hands. OK, here are the Circuit Descriptions:

1. Circuit labeled 1:
   • Switching Signal Circuit.
2. Circuit labeled 2:
   • Power (12 V) Circuit.

You don't have to worry about the color of the wires as long as you're able to identify the circuit using the photos in each test step.

Do's and Don'ts and Precautions

The tests that you're about to learn/do in this article are very easy and simple to do. But you still have to be on your toes and remain alert. Use common sense and take all necessary safety precautions. Here are some more suggestions:

1. Do not use a regular spark plug instead of a spark tester to test for spark. This method/technique for testing spark will give you a false spark result that will have you chasing the wrong diagnostic conclusion and in the process, waste time and money.
2. Do not remove the spark plug wire from the spark plug or the ignition coil while the engine is cranking to test for spark. This method of testing/verifying spark will fry the ignition coil.
3. Start your diagnostic from TEST 1, do not skip around from test to test unless instructed to do so by the TEST you are currently on.
4. Once again, use the recommended/indicated tools for all of your tests.
5. When testing for spark or the Switching Signal (TEST 1 and TEST 3) , your Chrysler (or Dodge or Plymouth) car may start, so be careful, stay alert and take all necessary safety precautions.

TEST 1: Testing For Spark

You may already know which cylinder is the one misfiring (if you have read the diagnostic trouble codes in the PCM memory with a scan tool) or you may not know which ignition coil to test first, either way I suggest that you test all six for spark.

This a pretty straight forward test, but one that has to be done with the HEI spark tester. Here are a couple of friendly reminders that'll help you to avoid wasting money and time (by not replacing a good part):

• Do not use a regular spark plug instead of a dedicated spark tester. The result you may get from using a regular spark plug IS NOT trustworthy.
• Do not pull the ignition coil off of its spark plug, as the engine is running, to see/hear if it's sparking. This method can ruin/fry the ignition coil and now you've got another problem on your hands.
• I don't recommend using any other type of spark tester. Buy the HEI spark tester, not an imitation or something similar.

OK, to get this show on the road, I'll stop yakking and this is what you need to do:

1. 1

   Remove the ignition coil.

2. 2

   Attach the HEI spark tester to the ignition coil (see photo above).

3. 3

   Connect the spark tester directly on the battery negative (-) terminal using a battery jump start cable.

4. 4

   Have your helper crank the engine while you observe the spark tester.
   
   NOTE: Be careful, the engine will start.

5. 5

   The spark tester should spark.

6. 6

   Re-install the ignition coil.

7. 7

   Repeat the test for all of the remaining ignition coils.

Let's take a look at what your test results mean:

CASE 1: You got spark on all of the ignition coils. This result lets you know that the ignition coils are good. The cause of the misfire lies in some other component. Go to: TEST 5: Carbon Tracks And Other Stuff.

CASE 2: You got NO spark from only one or several ignition coils. The next step is test that those ignition coils that did not spark are getting power and the Switching signal. Go to: TEST 2: Testing The Power Circuit (12 Volts).

CASE 3: You got NO spark from all six ignition coils. This usually indicates that the crankshaft position sensor on your Chrysler (or Dodge or Plymouth) car is bad. It is unheard of that all six ignition coils can go bad in one sitting. Although testing the crank sensor is beyond the scope of this article, you have at least eliminated the ignition coils as the cause of the problem.