How To Test The Ignition Coil (1995-1997 1.8L Toyota Corolla)

TEST 3: Checking The Distributor Cap For Spark

TEST 1 showed that some spark plugs aren't firing spark. That usually comes down to one of two things:

1. Bad spark plug wire: If the wire's too old, it won't deliver spark to the spark plug anymore.
2. Bad distributor cap: Corrosion or carbon tracks inside the distributor cap tower can block the spark from reaching the spark plug wire.

To figure out what's causing the issue, you're gonna do a quick spark test on the distributor cap tower(s) that connect to the non-sparking spark plug wire(s).

NOTE: If more than one spark plug wire did not spark in TEST 1, test them one by one.

Here's what to look for:

• If the distributor cap tower sparks: The spark plug wire is bad.
• If there's no spark: The distributor cap tower itself is the problem.

Let's dive in:

1. 1

   Make sure all spark plug wires are connected to their spark plugs (if any were unplugged earlier).

2. 2

   Pull off the spark plug wire from the distributor cap tower that didn't spark.
   
   NOTE: If multiple wires aren't sparking, test them one by one. For now, just remove one. You'll check the others in Step 8.

3. 3

   Insert the spark tester into the distributor cap tower.

4. 4

   Use a battery jump-start cable to Ground the spark tester to the battery's negative (-) terminal.
   
   NOTE: The jump-start cable also helps hold the spark tester in place inside the distributor cap tower.

5. 5

   Have someone crank the engine.
   
   CAUTION: The engine might start during this test, so stay alert and follow all safety precautions.

6. 6

   You'll get one of two results: Either the spark tester sparks or it doesn't.

7. 7

   Remove the spark tester and reconnect the spark plug wire.

8. 8

   Repeat the test for any other distributor cap towers connected to spark plug wires that didn't fire spark in TEST 1.

Here's what your test results mean:

CASE 1: The spark tester sparked. That's exactly what you wanna see.

This means the distributor cap tower is working fine, but the spark plug wire isn't. Swap out all the spark plug wires with a new set.

CASE 2: The spark tester DIDN'T spark. That points to a bad distributor cap.

Replace both the distributor cap and rotor, then go back and rerun TEST 1 to check the spark plug wires. All spark plug wires should now spark.

TEST 4: Making Sure The Ignition Coil Is Getting Power

By now, you've confirmed the following:

• None of the four spark plug wires fire spark (TEST 1).
• The ignition coil didn't spark either (TEST 2).

Our next troubleshooting step is to see if the ignition coil is actually getting 10-12 Volts DC when you turn the key to the ON position.

To do that, you're gonna measure the voltage right at the ignition coil's (+) terminal (check the image above).

Alright, here's what you gotta do:

1. 1

   Turn the key to the ON position, but don't crank the engine.

2. 2

   If the distributor cap is still on, take it off.

3. 3

   Set your multimeter to Volts DC mode.

4. 4

   Attach the black multimeter lead to the battery's negative (-) terminal.

5. 5

   Touch the red multimeter lead to the ignition coil's (+) terminal.

6. 6

   Your multimeter should read between 10 and 12 Volts DC.

Now, let's break down what your test results mean:

CASE 1: The multimeter reads 10 to 12 Volts DC. That's exactly what you wanna see.

Next up, you need to check if the ignition coil is getting its activation signal. Jump over to: TEST 5: Making Sure The Ignition Coil Is Getting Its Activation Signal.

CASE 2: The multimeter DIDN'T show 10 to 12 Volts DC. That usually points to an issue with the ignition switch not sending power to the ignition coil.

This guide doesn't cover how to diagnose that problem, so you'll have to track down what's blocking power from reaching the ignition coil. Once voltage is restored, the coil should start sparking again.

The following ignition system wiring diagrams may be of help:

• Ignition System Wiring Diagram (1995 1.8L Toyota Corolla).
• Ignition System Wiring Diagram (1996-1997 1.8L Toyota Corolla).

TEST 5: Making Sure The Ignition Coil Is Getting Its Activation Signal

Alright, here's what you've confirmed so far:

• TEST 1: None of the four spark plug wires are sparking.
• TEST 2: No spark from the ignition coil tower.
• TEST 4: 10 to 12 Volts are being supplied to the ignition coil.

Now it's time for the final check —let's see if the igniter is actually sending an activation signal to the coil.

To do this, you're gonna use a 12-volt automotive test light to probe the ignition coil's (-) terminal (check the image above).

Don't have a 12-volt test light? Here's the one I personally use and recommend: Lisle 28400 Heavy Duty 12 Volt Test Light (at: amazon.com).

IMPORTANT: For this test to work, the igniter's gotta stay plugged into its electrical connector.

Alright, let's get this done:

1. 1

   Clip the 12V test light's alligator clip to the battery's positive (+) terminal.

2. 2

   Touch the test light's metal probe to the ignition coil's (-) terminal.
   
   NOTE: Keep the probe in place while performing the next step.

3. 3

   Have your helper crank the engine while you watch the 12V test light.

4. 4

   The 12V test light should flash ON and OFF as the engine cranks.

Here's what your test results mean:

CASE 1: The 12V test light flashed ON and OFF. That's exactly what you wanna see, which confirms the igniter is doing its job and sending the activation signal to the ignition coil.

If you've already checked and confirmed:

• TEST 1: None of the four spark plug wires are firing.
• TEST 2: The ignition coil tower isn't sparking.
• TEST 4: The ignition coil is getting 10-12 Volts.
• This test: The ignition coil is receiving the activation signal.

Then that means the ignition coil is bad and needs to be replaced.

CASE 2: The 12V test light DIDN'T flash ON and OFF. That tells you the ignition coil isn't sparking because it's not getting an activation signal from the igniter.

The igniter is responsible for generating and sending that signal. Your next step? Test the igniter:

• How To Test The Igniter (1995-1997 1.8L Toyota Corolla).

More 1.8L Toyota Corolla Tutorials

You can find a complete list of 1.8L Toyota Corolla tutorials and wiring diagrams in this index:

• 1.8L Toyota Corolla Index of Articles.

Here's a sample of the tutorials you'll find there:

• How To Test The Throttle Position Sensor (1993-1997 1.8L Toyota Corolla).
• How To Do A Cylinder Balance Test (1993-1997 1.8L Toyota Corolla).
• How To Test The MAP Sensor (1993-1997 1.8L Toyota Corolla).
• How To Test For A Blown Head Gasket (1993-2008 1.8L Toyota Corolla).