How To Test The Igniter (1993-1995 1.6L Toyota Corolla)

TEST 3: Testing The Igniter Control Signal

So far, your igniter diagnostic tests have confirmed:

• The ignition coil isn't sparking.
• The igniter's getting power (TEST 1).
• The igniter's got a solid Ground connection (TEST 2).

Now, we're gonna check if the fuel injection computer (ECM) is sending an IGT activation signal to the igniter.

Like I mentioned earlier, when you crank the engine, the computer creates the IGT signal based on input from the distributor's pickup coil.

Basically, this IGT signal tells the igniter exactly when to fire the ignition coil.

For this test, we're gonna use an LED test light to see if the IGT signal shows up while cranking the engine.

IMPORTANT: Do not use a 12 Volt test light instead of an LED light, or you could damage the igniter. If you need to buy an LED light, you can buy it here: Oznium Flush Mount 12V LED Light (at: amazon.com).

IMPORTANT: For this test to work, the distributor's gotta stay connected to both of its electrical connectors. To tap into the IGT signal inside the wire, you'll need to use either a back probe on the connector or a wire-piercing probe. Check out an example of a wire-piercing probe here: Wire Piercing Probe Review (Power Probe PWPPPPP01) (at: easyautodiagnostics.com).

Here's how to do the test:

1. 1

   Hook up the red LED wire to the black (BLK) wire that connects to terminal 1 on the distributor's 6-wire connector.
   
   If you're using a wire-piercing probe, make sure to pierce the wire as far from the connector as possible.
   
   NOTE: Both the 2-wire and 6-wire distributor connectors must stay plugged into their engine wiring harness connectors.

2. 2

   Attach the black LED wire to the battery's negative (-) terminal.

3. 3

   Once the LED light is set up, have a helper crank the engine while you watch the LED light.

4. 4

   If the IGT signal is being delivered, the LED light should blink ON and OFF in steady pulses as the engine cranks.

Here's what your test results mean:

CASE 1: The LED light flashed ON and OFF. That's exactly what you wanna see —it means the igniter's getting its activation signal from the fuel injection computer.

Now, let's check if the igniter's sending the activation signal to the ignition coil. Head over to: TEST 4: Testing The Ignition Coil Activation Signal.

CASE 2: The LED light DID NOT flash ON and OFF. That means the igniter isn't getting its activation (IGT) signal from the fuel injection computer.

If there's no IGT signal, the igniter's not gonna trigger the ignition coil, so there won't be any spark going to the spark plug wires.

The most common reason for a missing IGT signal is a bad distributor pickup coil. Your next step is to test the distributor's pickup coil:

• How To Test The Distributor Pickup Coil (1993-1995 1.6L Toyota Corolla).

TEST 4: Testing The Ignition Coil Activation Signal

Up to this point, you have confirmed:

• The ignition coil isn't sparking.
• The igniter is getting power (TEST 1).
• The igniter has a solid connection to chassis Ground (TEST 2).
• The igniter is receiving the IGT activation signal (TEST 3).

Now, there's just one more thing to check —whether the igniter's actually activating the ignition coil.

To check for the presence of the ignition coil's activation signal, you're gonna need a 12-volt test light.

If you don't have one, here's the one I recommend: Lisle 28400 Heavy Duty 12 Volt Test Light (at: amazon.com).

IMPORTANT: All distributor connectors need to stay plugged in for this test to work.

Alright, let's get started:

1. 1

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

2. 2

   Touch the test light's metal probe to the ignition coil's (-) terminal (see image above).
   
   NOTE: Keep the probe in contact with the terminal for the next step.

3. 3

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

4. 4

   If the ignition coil's being activated, the 12V test light should blink ON and OFF repeatedly while the engine cranks.

Let's break down what your test result means:

CASE 1: The 12V test light flashed ON and OFF. That's exactly what you wanna see.

This proves the igniter is creating and sending the activation signal to the ignition coil, so the igniter (ignition control module) is working just fine.

If you've already confirmed the following, then the ignition coil's bad and needs to be replaced:

• There's no spark coming from the ignition coil.
• The igniter's getting battery power and is getting Ground (TEST 1 and TEST 2).
• The IGT activation signal is being received (TEST 3).
• The igniter is activating the ignition coil (this test section).

CASE 2: The 12V test light DID NOT flash ON and OFF. Without this activation signal, the ignition coil will not spark.

The igniter is bad and needs to be replaced, but only if you've already confirmed:

• The ignition coil isn't sparking.
• The igniter's getting battery power and has a solid Ground connection (TEST 1 and TEST 2).
• The igniter's receiving the IGT activation signal (TEST 3).
• The igniter IS NOT activating the ignition coil (this test section).

More 1.6L Toyota Corolla Tutorials

You can find a complete list of 1.6L Toyota Corolla tutorials and wiring diagrams in this index:

• 1.6L Toyota Corolla Index of Articles.

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

• How To Test Engine Compression (1989-1997 1.6L Toyota Corolla).
• How To Test The Throttle Position Sensor (1989-1997 1.6L Toyota Corolla).
• How To Do A Cylinder Balance Test (1989-1997 1.6L Toyota Corolla).
• How To Retrieve Toyota Corolla OBD I Trouble Codes (1990-1995 1.6L Toyota Corolla).