How To Test The Ignition Coils Suzuki Verona (2004-2005)

TEST 2: Testing The Power (12 V) Circuit

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.

These are the test steps:

1. 1

   Disconnect the ignition coil that did not spark from its electrical connector.

2. 2

   Put the multimeter in Volts DC mode.

3. 3

   Connect the black multimeter test lead to the battery negative (-) terminal.

4. 4

   Gently probe the female terminal that connects to the wire labeled with the number 1 with the red multimeter test lead.

5. 5

   Have your helper turn the key to the ON position.

6. 6

   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 interpret your test result:

CASE 1: The multimeter registered 10-12 Volts (or the test light lit up). This tells you the power circuit is OK and is delivering voltage. The next step is to test the Ground circuit, go to: TEST 3: Testing The Ground Circuit.

CASE 2: The multimeter DID NOT register 10-12 Volts (or the test light DID NOT light up). This test result confirms 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

OK, you're here because in TEST 2 your multimeter (or 12 Volt 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.

These are the test steps:

1. 1

   Disconnect the ignition coil that did not spark from its electrical connector.

2. 2

   Put the multimeter in Volts DC mode.

3. 3

   Connect the red multimeter test lead to the battery positive (+) terminal.

4. 4

   Gently probe the female terminal that connects to the wire labeled with the number 3 with the red multimeter test lead.

5. 5

   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 interpret your test result:

CASE 1: The multimeter registered 11-12 Volts (or the test light lit up). This test result tells you the Ground circuit is OK. The next step is to verify that the ignition coil is receiving the Triggering Signal, go to: TEST 4: Testing For The Triggering Signal.

CASE 2: The multimeter DID NOT register 11-12 Volts (or the test light DID NOT light up). This test result means 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

So far, you have confirmed:

• The ignition coil is not sparking
• The ignition coil is getting 12 Volts.
• The ignition coil is getting Ground.

The next step is to verify that that ignition coil's is receiving an activation signal from the fuel injection computer.

NOTE: Testing for the Triggering signal is done with the ignition coil connected to its connector. You'll need to use a back-probe on the connector or a wire-piercing probe on the wire to read the activation signal. You can see an example of this tool and where to buy it here: Wire-Piercing Probe.

Let's get started:

1. 1

   Put the multimeter in Hertz (Hz) mode.

2. 2

   Connect the red multimeter test lead to the battery positive (+) terminal.

3. 3

   Connect the black multimeter test lead to wire labeled with the number 2 (see the photo above) with the black multimeter test lead (using an appropriate tool to pierce the wire).

4. 4

   Have your helper crank the engine while you observe the multimeter.

5. 5

   You should see fluctuating values of 30 to 60 Hertz as the engine starts and runs on your multimeter.

Let's interpret your multimeter test result:

CASE 1: The multimeter registered 30 to 60 Hertz (Hz) as the engine cranked and started. This test result confirms the Triggering signal is present. This result indicates that the Coil-On-Plug Ignition Coil on your Suzuki is bad and needs to be replaced.

CASE 2: The multimeter DID NOT register 30 to 60 Hertz (Hz) as the engine cranked and started. Re-check all of your connections and repeat the test.

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.

TEST 5: 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 photo above, 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?: 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.