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

TEST 3: Testing The Igniter Control Signal

Here's what you've confirmed so far:

• The ignition coil isn't sparking.
• The igniter is getting 10 to 12 Volts DC (TEST 1).
• The igniter's case is properly Grounded (TEST 2).

Now, we're gonna see if the fuel injection computer is actually sending an IGT activation signal to the igniter.

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

If the computer isn't sending that IGT signal to the igniter, then the ignition coil won't fire spark to the spark plugs.

To check if the IGT signal is present, we're gonna use an LED test light while cranking the engine.

IMPORTANT: Don't use a regular 12 Volt test light instead of an LED light —it could damage the igniter. If you need an LED light, you can get one here: Oznium Flush Mount 12V LED Light (at: amazon.com).

IMPORTANT: The igniter must remain connected to its electrical connector for this test to function. To access the IGT signal inside the wire, you'll need to use either a back probe on the connector or a wiring piercing probe. You can see an example of a wiring piercing probe here: Wire Piercing Probe Review (Power Probe PWPPPPP01) (at: easyautodiagnostics.com).

Here's what you gotta do:

1. 1

   Connect the red LED wire to the BLK or YEL/GRN wire that corresponds to terminal 2 of the igniter's 5-wire connector.
   
   1995: The BLK wire connects to female terminal number 2 on the igniter's 5-wire connector (check the illustration above).
   
   1996-1997: The YEL/GRN wire connects to female terminal number 2 on the igniter's 5-wire connector (check the illustration above).
   
   NOTE: Leave the igniter plugged into its 5-wire connector.

2. 2

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

3. 3

   With the LED light set up, have a helper crank the engine while you keep an eye on the LED.

4. 4

   If the IGT signal is present, the LED should flash ON and OFF in a steady rhythm while the engine cranks.

Here's what your test results tell you:

CASE 1: The LED 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.

Next, you need to check if the igniter is actually sending the activation signal to the ignition coil. Head over to: TEST 4: Testing The Ignition Coil Activation Signal.

CASE 2: The LED DID NOT flash ON and OFF. That means the igniter isn't receiving the IGT signal from the fuel injection computer.

If the igniter doesn't get the IGT signal, it won't activate the ignition coil, so no spark reaches the spark plugs.

The most common reason for a missing IGT signal is a faulty distributor pickup coil or CKP sensor. Your next step is to test the distributor's pickup coil (G2 sensor) and the crankshaft position sensor.

• How To Test The Distributor Pickup Coil (1995-1997 1.8L Toyota Corolla).
• How To Test The CKP Sensor (1995-1997 1.8L Toyota Corolla).

TEST 4: Testing The Ignition Coil Activation Signal

All of your previous tests have confirmed:

• The ignition coil isn't sparking.
• The igniter's getting 10 to 12 Volts (TEST 1).
• The igniter's case has a solid chassis Ground connection (TEST 2).
• The igniter is receiving the IGT activation signal (TEST 3).

Now, it's time for the final check —making sure the igniter is actually triggering the ignition coil to spark.

To check that that the igniter is generating the ignition coil's activation signal, we're gonna use a 12 Volt test light.

This signal reaches the ignition coil through the black (BLK) wire, which connects to female terminal number 5 on the igniter's 5-wire connector.

IMPORTANT: The igniter has to stay connected to its electrical connector for this test to work. To tap into the IGT signal inside the wire, you'll need either a back probe on the connector or a wiring piercing probe. You can check out an example of a wiring piercing probe here: Wire Piercing Probe Review (Power Probe PWPPPPP01) (at: easyautodiagnostics.com).

These are the test steps:

1. 1

   Clip the alligator end of the 12V test light to the battery's negative (-) post.

2. 2

   Use the test light's metal probe to tap into the BLK wire that connects to female terminal 5.
   
   NOTE: The probe must pierce through the wire's insulation to make contact with the copper inside.
   
   IMPORTANT: Make sure to pierce the wire as far from the connector as possible.

3. 3

   Have a helper crank the engine while you keep an eye on the test light.

4. 4

   The 12V test light should flash ON and OFF repeatedly the entire time the engine is cranking.

Let's take a look at your test results:

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

This confirms that the igniter is working —it's generating and sending the activation signal to the ignition coil like it should.

If you've already verified:

• The ignition coil isn't sparking.
• The igniter is getting battery power and Ground (TEST 1 and TEST 2).
• The IGT activation signal is reaching the igniter (TEST 3).
• The igniter is generating the ignition coil activation signal (this test section).

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

CASE 2: The 12V test light DID NOT flash ON and OFF. That means the igniter isn't doing its job.

With this result, you can confirm the igniter is faulty and needs replacing, but only if you've already checked and confirmed:

• The ignition coil isn't producing spark.
• The igniter has battery power and a solid Ground (TEST 1 and TEST 2).
• The IGT activation signal is being sent to the igniter (TEST 3).
• The igniter is NOT generating the ignition coil activation signal (this test section).

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 Diagnose A Broken Timing Belt (1993-1997 1.6L Toyota Corolla).
• How To Test For A Blown Head Gasket (1993-2008 1.8L Toyota Corolla).