How To Test The Coil on Plug Ignition Coil (Honda 3.0L)

If you've been wondering how to test the Coil-on-Plug ignition coils on your Honda Accord or Honda Odyssey (2000, 2001, 2002, 2003 -3.0L V6) to see if one or several are BAD and are causing a misfire... this is the article for you.

As is the custom here at easyautodiagnostics.com, the tests steps are explained in detail and the diagnostic/troubleshooting is accomplish in several easy steps.

This info applies to the 00-03 Honda Accord or Honda Odyssey with the 3.0L 6 cylinder engine. If you'd like to read a primer on how to test Coil-on-Plug ignition coils that are not covered by this article, read: Testing And Troubleshooting 3 Wire COP Ignition Coils.

Common Symptoms Of A BAD Coil-on-Plug Ignition Coil

This is not the most definitive list on the subject, but does cover the majority of symptoms I've seen on this type of ignition system:

  1. Misfire codes that light up the CHECK ENGINE LIGHT (CEL) on your instrument cluster.
  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?

A Scan Tool (Automotive Diagnostics Scanner) is not needed. Even if you suspect a misfire, you don't need a scan tool to find out which cylinder is the one that is misfiring. You can perform the cylinder balance test yourself on your Honda Accord or Honda Odyssey, Test 1 will help you with this. You'll need:

  1. An HEI spark tester.
  2. Battery jump start cables.
  3. A digital multimeter.
    1. This multimeter must be able to read Hertz frequency.
  4. A helper.
    1. You'll need someone to help you crank the engine while you perform the tests in the engine compartment.
  5. A repair manual.
    1. For whatever remove and replace info you'll need that is not covered by this article.

Circuit Descriptions Of The C-O-P Ignition Coil Connector

How To Test The Coil on Plug Ignition Coil (Honda 3.0L)

OK, to test the Coil-on-Plug ignition coils on your Honda Accord (Odyssey), you need to know what each wire (circuit) does in the connector. Here are the Circuit descriptions:

  1. Circuit labeled 1:
    1. Power (12 V) Circuit.
  2. Circuit labeled 2:
    1. Ground Circuit.
  3. Circuit labeled 3:
    1. Trigger Signal Circuit.

The above circuit descriptions are shared by all of the six Coil-on-Plug ignition coils on your Honda Accord (or Odyssey). So, whether you're testing the number 1 cylinder ignition coil or the number 4 cylinder ignition coil (or whichever ignition coil)... the above info applies.

To test these circuits, it's not necessary to unplug the ignition coil's connector therefore, I recommend testing for each Signal with the connector connected. Also, using a wire-piercing probe is the most effective and easy way of getting to the signal. If you need to see what this tool looks like, click here: Wire-Piercing Probe.


TEST 1: Testing For Spark

Testing For Spark. How To Test The Coil on Plug Ignition Coil (Honda 3.0L)

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

  1. 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.
  2. 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.
  3. I don't recommend using any other type of spark tester. Buy the HEI spark tester... not an imitation or something similar.

OK, now on with the show... I'm gonna' assume that you don't know which cylinder is the one that is misfiring or with the BAD ignition coil or coils... so then, the very first thing that has to be done is to:

  1. Remove the first Coil-on-Plug ignition coil (which one? it doesn't matter since you're gonna' test them all).
  2. Attach the HEI spark tester (or an equivalent spark tester) to the Coil-on-Plug ignition coil (as shown in the photos in the image viewer).
  3. Attach the HEI spark tester to a good ground point by using a battery jump start cable (my preferred method).
  4. Have your helper crank the engine while you observe the spark tester.
  5. After noticing the result, which will be either spark or No spark, disconnect the spark tester and put the ignition coil back in place.
  6. Repeat the test for all of the remaining Coil-on-Plug ignition coils.
  7. You're gonna' get one of two results: spark or No spark.

Interpreting The Results

CASE 1: If you got spark, from all of the Honda Accord's (or Odyssey's) Coil-on-Plug ignition coils... then the ignition coils are good. The cause of the misfire is something else. Go to TEST 5.

CASE 2: If you got spark, from some but NOT all of the Honda Accord's (or Odyssey's) Coil-on-Plug ignition coils... then the ones that did not fire off spark are probably BAD. To make sure you need to verify that the ignition coil (the one that did not spark) is receiving 12 Volts and the Triggering Signal. Go to TEST 1.

CASE 3: If you got NO spark, from none of the Honda Accord's (or Odyssey's) Coil-on-Plug ignition coils... then the cause of your Honda's NO START Condition is not due to the ignition coils. It is rare (next to impossible) for all of the ignition coils to go BAD at the exact same time. Testing this condition is beyond the scope of this article but possible causes could be a BAD Crankshaft Position Sensor, BAD Ignition Switch, etc.

TEST 2: Testing The Power (12 V) Circuit

Making Sure The Ingition Coil Is Getting Power. How To Test The Coil on Plug Ignition Coil (Honda 3.0L)

OK, you're here because in TEST 1 you got a NO SPARK result from one of several ignition coils. The next step is to verify that that ignition coil or coils are receiving power.

Testing for Power can be accomplished by testing the COP coils connected or disconnected to their connectors. The method I recommend to use is with them connected to their connectors and with a Wire-Piercing Probe (to see what this tool looks like, click here: Wire-Piercing Probe. Now, if you decide to unplug the connector to test the front of the female terminal (of the connector) for 12 Volts... be careful not to damage it.

  1. Remove the Coil-on-Plug ignition coil that did not spark and connect the HEI spark tester to it (although you're no longer testing for spark, the spark tester must be connected just as a safety precaution).
  2. The three wires in the ignition coil's connector are usually sheathed in a hard plastic tube... remove enough of this plastic tube to expose the three wires for testing.
  3. With the ignition coil connected to its connector.
  4. Put the multimeter in VOLTS DC mode.
  5. Probe the circuit labeled with the number 1 (see photo in image viewer) with the RED multimeter test lead (using an appropriate tool to pierce the wire).
  6. With the BLACK lead of the multimeter probe the BATT (-) NEGATIVE terminal.
  7. Have your helper turn the key to the ON position.
  8. You should see 11-12 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: If the multimeter registered 11-12 Volts (or the test light lit up), then the power circuit is OK and is delivering voltage. The next step is to test the ground circuit, go to TEST 3

CASE 2: If the multimeter DID NOT register 11-12 Volts (or the test light DID NOT light up), then the power circuit has a problem. This result eliminates the COP ignition coil as the source of the misfire condition. The power circuit is shared by all of the COP ignition coils.

TEST 3: Testing The Ground Circuit

Making Sure The Ingition Coil Is Getting Ground. How To Test The Coil on Plug Ignition Coil (Honda 3.0L)

OK, you're here because in TEST 2 your multimeter (or test light) confirms that the power circuit is OK. The next step is to verify that that ignition coil's ground circuit is doing its job.

Testing for ground can be accomplished by testing the COP coils connected or disconnected to their connectors. The method I recommend to use is with them connected to their connectors and with a Wire-Piercing Probe (to see what this tool looks like, click here: Wire-Piercing Probe. Now, if you decide to unplug the connector to test the front of the female terminal (of the connector) for ground... be careful not to damage it.

With the Coil-on-Plug ignition coil that did not spark already removed and still connected to the HEI spark tester and to its connector:

  1. Put the multimeter in VOLTS DC mode.
  2. Probe the circuit labeled with the number 2 (see photo in image viewer) with the BLACK multimeter test lead (using an appropriate tool to pierce the wire).
  3. With the RED lead of the multimeter probe the BATT (+) positive terminal.
  4. You should see 11-12 Volts on your multimeter, or if you're using a test light... the test light should light up.

CASE 1: If the multimeter registered 11-12 Volts (or the test light lit up), then the ground circuit is OK. The next step is to verify that the ignition coil is receiving the Triggering Signal, go to TEST 4.

CASE 2: If the multimeter DID NOT register 11-12 Volts (or the test light DID NOT light up), then the ground circuit has a problem. This result eliminates the COP ignition coil as the source of the misfire condition. The ground circuit is shared by all of the COP ignition coils.


TEST 4: Testing for the Triggering Signal

Making Sure The Fuel Injection Computer Is Activating The Ignition Coil. How To Test The Coil on Plug Ignition Coil (Honda 3.0L)

OK, you're here because you have confirmed that the ignition coil is not sparking, has 12 Volts and ground. The next step is to verify that that ignition coil's is receiving the Triggering signal from the Fuel Injection Computer.

There are two ways of doing this test... with a multimeter that can read Hertz frequency or just by swapping coils. If you just want to test them by swapping COP coils, go to the next heading below.

Testing for the Triggering Signal should be done with the ignition coil connected to its connector. The method I recommend to use is with them connected to their connectors and with a Wire-Piercing Probe (to see what this tool looks like, click here: Wire-Piercing Probe.

With the Coil-on-Plug ignition coil that did not spark already removed and still connected to the HEI spark tester and to its connector:

  1. Put the multimeter in Hertz (Hz) mode.
  2. Probe the circuit labeled with the number 3 (see photo in image viewer) with the BLACK multimeter test lead (using an appropriate tool to pierce the wire).
  3. With the RED lead of the multimeter probe the BATT (+) positive terminal.
  4. You should see fluctuating values of 30 to 60 Hertz as the engine starts and runs on your multimeter.

CASE 1: If the multimeter registered 30 to 60 Hertz (Hz) as the engine cranked and started, then the Triggering Signal is present. This result indicates that the Coil-on-Plug ignition coil on your Honda is BAD and needs to be replaced.

CASE 2: If the multimeter DID NOT register 30 to 60 Hertz (Hz) as the engine cranked and started, re-check all of you connections and repeat the test again. If still no Hertz readings, then this results eliminates the ignition coil as the source of the NO SPARK condition/misfire, since without the Triggering Signal the ignition coil will not work.

Testing The Triggering Signal Without A Multimeter

Making sure that the Triggering Signal is present can be done without a multimeter and in this test step I'll show you how:

  1. Remove the COP coil that did not spark and set it aside.
  2. Remove one of the adjacent COP ignition coils that does spark.
  3. Now connect the COP ignition coil (that sparks) to your HEI spark tester and then connect it to the electrical connector of the COP coil that does not spark.
  4. When all is ready, have your trusty assistant crank the engine and notice if the HEI spark tester sparks. Be careful, the engine may start.
  5. If the COP coil sparks, then you now know that the Triggering Signal is present in this connector.

Here are the test result interpretations:

CASE 1: If you got spark, then the Triggering Signal is present. This result indicates, beyond a shadow of a doubt, that the Coil-on-Plug ignition coil on your Honda is BAD and needs to be replaced. Replacing the ignition coil will solve the misfire condition.

CASE 1: If you got NO spark, re-check all of you connections and repeat the test again. If still no spark, then this results eliminates the ignition coil as the source of the NO SPARK condition/misfire, since without the Triggering Signal the COP ignition coil will not work.


TEST 6: Checking for Carbon Tracks

Checking for Carbon Tracks

If all of the spark plug boots fired off spark in TEST 1 and yet the vehicle is experiencing a misfire condition, then the most likely causes are: 1) the spark plug boots spark plugs have developed carbon tracks or 2) the spark plugs and spark plug boots are swimming in engine oil or 3) both of the aforementioned conditions. All of these conditions are a very common occurrence in this type of coil-on-Plug ignition system.

If the spark plug boots spark plugs are swimming in engine oil, it's usually due to the valve cover gasket leaking oil into the spark plug tubes. This oil will cause the ignition system to misfire and/or cause carbon tracks to form as the spark cooks the oil.

In the image viewer you'll see what a carbon track looks like on the spark plug boot and on the spark plugs. The next step is to remove the spark plugs and spark plug boots to visually inspect them for carbon tracks and/or to see if the are all oil-soaked.

If the spark plugs are oil-soaked and/or with carbon tracks, you'll need to replace them all along with the spark plug boots. Failure to replace one without the other will only make the carbon track return and/or continue to misfire still.

What If No Carbon Tracks Or Cracks Exist?

Now, if no carbon tracks are visible on any of the spark plugs, or spark plug boots... then the ignition system is not the cause of your misfire condition. I would check engine compression and the fuel injectors among several things.

The following test tutorials may be of help:

  1. How To Test Engine Compression (Honda 3.0L) (at: troubleshootmyvehicle.com).
  2. How To Test Misfire Codes (Honda 3.0L) (at: troubleshootmyvehicle.com).
  3. How To Troubleshoot A No Start (Honda 3.0L) (at: troubleshootmyvehicle.com).
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