How To Test The Coil Pack (2001-2008 Chrysler 3.3L, 3.8L)

This article will help you troubleshoot a misfire condition that might be setting one or several of the following diagnostic trouble codes (DTCs): P0300, P0301, P0302, P0303, P0304, P0305, P0306 and/or a bad ignition coil pack on your 2001-2009 Chrysler (or Dodge) 3.3L or 3.8L Town and Country, Voyager, Caravan, or Grand Caravan mini-van.

If this is not the Chrysler V6 coil pack Test you need, there are two more and you can find them at: Chrysler 3.3L, 3.8L Main Index Of Articles.

Symptoms Of A Bad Chrysler Coil Pack

When the ignition coil pack or the spark plug wires are bad, your 3.3L or 3.8L Chrysler (or Dodge) mini-van will display one or more of the following symptoms:

1. The mini-van idles rough and wants to stall (die).
2. When you accelerate the car, it has no power.
3. Really bad gas mileage.
4. The vehicle will not start.
5. The mini-van will not run on all cylinders.
6. Misfire codes that are lighting up the check engine light on your instrument cluster.
   • P0300, P0301, P0302, P0303, P0304, P0305, P0306.
7. Rotten egg smell coming out of the tail-pipe.

Precautions, Do's And Don'ts

The tests you're about to learn are pretty simple and easy but, since most of them are done with the engine cranking, you need to be alert and on your toes. Take all necessary safety precautions to keep your fingers, hands and entire self safe. Here are a few other tips and suggestions:

TIP 1: Do not use a regular spark plug instead of a spark tester to test for spark. Using a spark plug to test for spark is the surest way to guarantee a fake spark result that will have you wasting time and money. Use or buy the HEI spark tester.

TIP 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 procedure will fry the ignition coil pack and you run the risk of getting shocked.

TIP 3: It's important that you start your diagnostic from TEST 1, do not skip around from test to test unless specifically instructed to do so by the TEST you are currently on.

TIP 4: Do not use a test light where an LED light is called for. Use the recommended/indicated tools for all of your tests.

TIP 5: Read the entire article first. The testing of the coil pack is an easy and straightforward affair. The article may seem like a long one and a lot of reading, but once you start testing, you'll see how easy the tests are.

TIP 6: Before you do the actual tests on your car or mini-van, it's important the you know what ‘Paired Cylinders’ and ‘Non-Paired Cylinders’ mean to successfully diagnose a bad coil pack.

TIP 7: Think safety all of the time. Some of the tests are done with the engine cranking, so you have to be on your toes and take all necessary safety precautions.

TIP 8: Most of the tests require a helper to crank the engine. My suggestion is to have him or her wait outside of the vehicle before and after you need them to crank the engine. This will avoid having your helper crank the engine accidentally.

What Tools Do I Need?

To successfully use this information to diagnose and troubleshoot the coil pack on your 3.3L or 3.8L Chrysler mini-van, you need a few specific tools. Don't worry, none of this stuff is expensive.:

1. A 12 Volt automotive test light.
2. A multimeter (don't have a digital multimeter? Need to buy one? Click here to see my recommendations: Buying A Digital Multimeter For Automotive Diagnostic Testing).
3. An LED light.
   • To see what this tool looks like, click here: The LED Light Test Tool And How To Make One.
4. An HEI spark tester
   • This tool is a must have since it's the most accurate spark tester you can own (don't have an HEI spark tester? Need to buy one? You can buy it here: OTC 6589 Electronic Ignition Spark Tester).
5. Battery jump start cables.
6. Someone to help you crank the car.

The most important tool out of the whole list above, is the HEI spark tester and it's NOT because I own the company that makes the HEI spark tester. The principal reasons are:

1.) This spark tester is accurate. From personal experience I can tell you that I have used most of the spark tester on the market and only the HEI spark tester delivers a true spark or no-spark test result I can trust 100% of the time.

2.) You are not gonna' spend an arm and a leg, since the HEI spark tester is inexpensive. Unfortunately, your local auto parts store probably won't carry it, you'll have to buy it online, but because this spark tester is extremely accurate, it's well worth the wait.

Coil Pack Circuit Descriptions

It's important to know what the 4 wires coming out of the Chrysler coil pack connector do and below is a brief description of each.

• Circuit labeled 1:
  • Switching Signal Circuit for Spark Plugs 3 and 6.
• Circuit labeled 2:
  • Switching Signal Circuit for Spark Plugs 1 and 4.
• Circuit labeled 3:
  • Power (12 Volts) Circuit
• Circuit labeled 4:
  • Switching Signal Circuit for Spark Plugs 2 and 5.

You've probably noticed that there's no mention of the color of the wires of the three wires coming out of the connector, well the color is not important (to take advantage of the info in this article) as long as you're able to correctly identify the circuit by its number in the photos supplied.

Where To Buy The Ignition Coil And Save

The following links will help you comparison shop for the ignition coil pack:

Not sure if the above ignition coils fit your particular vehicle? Don't worry, once you get to the site they'll make sure it fits by asking you the specifics of your vehicle. If they don't fit, they'll find you the right ones.

How The Coil Pack Works

The PCM (Powertrain Control Module=Fuel Injection Computer) is the one that controls the whole show in this type of ignition system since the ‘Ignition Control Module’ function is handled by the PCM itself. So, in a nutshell, here's what happens when you turn the key to crank and start the mini-van:

1. The Auto Shut Down (ASD) Relay provides the ignition coil pack with 12 Volts (only when the engine is cranking or running).
2. The crankshaft position sensor starts to create its CKP signal, as the engine cranks.
3. The CKP Signal, upon being received by the PCM along with other necessary sensor information, starts to do its little song and dance and decides which ignition coil (within the coil pack assembly) to fire. It does this by sending the coil pack three different Switching signals (thru' separate circuits).
   • The term Switching signal describes the PCM's action of switching the Primary Current (12 Volts), flowing thru' each ignition coil within the coil pack, ON and OFF by interrupting their Ground path. It's this control signal that makes the ignition coils fire spark.
4. The coil pack is made up of three separate and individual ignition coils, therefore each one gets its own switching signal from the PCM. Each ignition coil within the coil pack has two towers that feed spark to two cylinders at the same time. These two cylinders (that get spark at the same time) are called ‘Paired Cylinders’
   • One ignition coil within the coil pack fires spark to cylinders 3 and 6. So, Cylinders 3 and 6 are ‘Paired Cylinders’.
   • One ignition coil fires cylinders 1 and 4. So, Cylinders 1 and 4 are ‘Paired Cylinders’.
   • The other ignition coil fires cylinders 2 and 5. So, Cylinders 2 and 5 are ‘Paired Cylinders’.
5. As each individual ignition coil, within the ignition coil pack, get their Switching signal, they then fire spark to two different cylinders at the exact same time (in what's known as the Waste Spark method).

To test the Chrysler ignition coil (for these specific 3.3L, 3.8L Chrysler engines this article covers) the only thing that you have to worry about is knowing that two cylinders get spark at the exact same time (#3 and #6, #1 and #4, #2 and #5) from separate ignition coils within the coil pack assembly.

Do I Need To Test All Of The Spark Plug Wires?

You don't need to test all six spark plugs. Especially since the 3 spark plug wires that face the firewall are hard to get to (actually, they are a complete pain the neck to get to).

To help you get the maximum benefit of this article, I'll go into some detail why you don't have to and under what conditions you would need to test them all:

TEST ONLY 1 SPARK PLUG WIRE

1. You have a specific misfire code such as: P0301, P302, P0303, P0304, P305, P0306 and you only want to test that specific cylinder.
2. You have already replaced the ignition coil pack, spark plug wires, and the spark plugs with a new ones and you are still getting a specific misfire code lighting up the check engine.

TEST ALL SPARK PLUG WIRES

1. You have a P0300 misfire code. This code doesn't specify which cylinder is the one misfiring and so you'll need to test them all.
2. The PCM is not registering any misfire trouble codes to help you find out which cylinder is the one affected (but the engine is misfiring), you'll have to test them all (yeah, I know, life sucks).

TEST 1: Checking For Spark

Before you physically start this test, you must fully understand the principle behind ‘Paired Cylinder’ and ‘Non-Paired Cylinder’. If you need help figuring this out, take a look at the section: How The Coil Pack Works.

One more section that will help you a lot with the tests in this article is: Precautions, Do's And Don'ts.

The first order of business is to find out if all the spark plug wires are delivering spark or not to the spark plugs. You don't have to test all of the spark plug wires, although I would. For more info on this, see/read the section: Do I Need To Test All Of The Spark Plug Wires?

You'll need someone to help you to crank the engine. OK, this is what you'll need to do:

1. 1

   Disconnect the spark plug wire from the spark plug that you're gonna' test and connect the HEI spark tester to the spark plug wire.

2. 2

   Ground the HEI spark tester directly on the battery negative (-) terminal with a jump start cable.

3. 3

   When ready, have your helper crank the engine as you observe the spark tester.

4. 4

   You'll obtain one of two results from the spark tester: Spark or no spark jumping across the air gap of the HEI spark tester.

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

CASE 1: You got spark from all six spark plug wires. This tells you that the coil pack and the spark plug wires, on your 3.3L or 3.8L Chrysler mini-van, are OK and not the cause of the misfire condition.

CASE 2: You got NO SPARK from only one spark plug wire. This result means one of two things: either that the spark plug wire is bad or the ignition coil pack is fried. You can find out for sure which one is fried with: TEST 2: Testing For Spark Directly On The Coil Tower.

CASE 3: You got a no-spark result from two ‘Paired Cylinder’ spark plug wires. This usually means that the coil pack is bad on your mini-van, but not always. To further verify/confirm this, go to: TEST 3: Testing For Spark Directly On The Coil Tower.

CASE 4: You got a no-spark result from two ‘Non-Paired Cylinder’ spark plug wires. This usually means that the coil pack is bad or that the spark plug wires are fried on your mini-van. To further verify/confirm this, continue to: TEST 2: Testing For Spark Directly On The Coil Tower.

CASE 5: You got a no-spark result from all of the spark plug wires. This usually means that the crank sensor is bad. The next step is to make sure that the ignition coil is getting power (12 Volts) and then see if the Powertrain Control Module (Fuel Injection Computer) is activating the ignition coils within the coil pack. Go to: TEST 4: Checking Coil Pack Is Getting Power.