How To Test The Igniter (1991-1994 1.5L Toyota Tercel)

TEST 2: Making Sure The Igniter Is Getting Ground

After confirming in TEST 1 that the igniter is receiving power, the next step is to verify that it's properly grounded.

The igniter gets Ground through its metal case. To check that it's properly Grounded, we'll use a multimeter to check for continuity between the igniter's case and the battery negative (-) post.

If the igniter's case is properly Grounded to its mounting location, the multimeter will register continuity between it and the battery negative (-) post.

Let's get started:

1. 1

   Disconnect the igniter from its 5-wire electrical connector.

2. 2

   Disconnect the battery positive (+) cable from its cable.
   
   NOTE: Leave the battery negative (-) cable connected to the battery negative (-) post.

3. 3

   Set your multimeter to Ohms (Ω) mode.

4. 4

   Place one multimeter test lead on the igniter's metal case.

5. 5

   Place the other multimeter test lead on the center of the battery negative (-) post.

6. 6

   The multimeter should read continuity.
   
   If there's continuity (a low resistance reading, usually close to 0 Ohms), the igniter is properly grounded.
   
   If there's no continuity (infinite resistance or OL on the display), the igniter is not grounded.

Let's take a look at what your test results mean:

CASE 1: The igniter has continuity to Ground. This is the correct and expected test result.

Now we need to check that igniter is receiving the IGT signal from the fuel injection computer. Go to: TEST 3: Testing The Igniter Control Signal.

CASE 2: The igniter DOES NOT have continuity to Ground. This is usually due to poor contact or corrosion between the igniter's case and its mounting surface.

Your next step is to inspect and clean the igniter's mounting points to ensure proper metal-to-metal contact. Once the igniter's case is properly grounded, the igniter should function as expected.

TEST 3: Testing The Igniter Control Signal

So far, your initial tests have confirmed:

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

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

As I mentioned at the beginning of this tutorial, when you crank the engine, the computer generates the IGT signal based on input signal from the distributor's pickup coil. This IGT signal tells the igniter when to activate the ignition coil.

For this test, we'll use an LED test light to detect the IGT signal while cranking the engine.

IMPORTANT: Do not use a 12 Volt test light instead of an LED light, or you'll 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: 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).

These are the test steps:

1. 1

   Connect the red LED wire to the light green (LT GRN) wire of the igniter's electrical connector.
   
   The LT GRN wire is the one that corresponds to female terminal number 2 of the igniter's 5-wire connector (see illustration above).
   
   NOTE: The igniter must remain connected to its electrical connector.

2. 2

   Connect the black LED wire to the battery negative (-) terminal.

3. 3

   After the LED light is set up, have your helper crank the engine as you observe the LED light.

4. 4

   The LED light should flash ON and OFF in steady pulses as the engine is cranking if the IGT signal is present.

Let's take a look at what your test results mean:

CASE 1: The LED light flashed ON and OFF. This is the correct and expected test result and tells you that the igniter is getting its activation signal from the fuel injection computer.

The next step is to make sure that the igniter is now creating the activation signal for the ignition coil. Go to: TEST 4: Testing The Ignition Coil Activation Signal.

CASE 2: The LED light DID NOT flash ON and OFF. This tells you that the igniter is not receiving its activation (IGT) signal from the fuel injection computer.

If the igniter doesn't receive its IGT signal, it's not gonna activate the ignition coil to start creating and sending spark to the distributor.

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

• How To Test The Distributor Pickup Coil (1991-1994 1.5L Toyota Tercel).

TEST 4: Testing The Ignition Coil Activation Signal

At this point, your previous diagnostic tests have confirmed:

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

Now, it's time for the final test: verifying whether the igniter is sending the +B2 activation signal to the ignition coil.

This +B2 signal is critical since it triggers the ignition coil to fire spark. To check for it, we'll use a 12 Volt test light.

The wire that delivers this signal is the black with blue stripe (BLK/BLU) wire of the igniter's 5-wire connector.

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).

Let's begin:

1. 1

   Connect the alligator clip of the 12V test light to the battery negative (-) post.

2. 2

   Probe the BLK/BLU wire with the metal probe of the 12V test light.
   
   NOTE: The 12V test light's metal probe has to pierce the insulation of the BLK/BLU wire and make contact with the copper wiring inside.
   
   IMPORTANT: Pierce the wire as far away as possible from the connector.

3. 3

   Have your helper crank the engine while you observe the test light.

4. 4

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

Let's interpret your test result:

CASE 1: The 12V test light flashed ON and OFF. This is the correct and expected test result.

This result confirms that the igniter is creating and sending an activation signal to the ignition coil and that the igniter (ignition control module) is functioning correctly.

You can conclude that the ignition coil is bad and needs replacement if you have checked and confirmed:

• The ignition coil isn't producing spark.
• The igniter is receiving battery power and has a solid Ground connection (TEST 1 and TEST 2).
• The igniter is receiving the IGT activation signal (TEST 3).
• The igniter is producing and sending the +B2 signal to the ignition coil (this test section).

CASE 2: The 12V test light DID NOT flash ON and OFF. This tells you that the igniter is bad.

You can conclude that the igniter is defective and needs replacement only if you have tested and confirmed that:

• The ignition coil isn't producing spark.
• The igniter is receiving battery power and has a solid Ground connection (TEST 1 and TEST 2).
• The igniter is receiving the IGT activation signal (TEST 3).
• The igniter IS NOT producing nor sending the +B2 signal to the ignition coil (this test section).

More 1.5L Toyota Tercel Tutorials

You can find a complete list of 1.5L Toyota Tercel tutorials and wiring diagrams in this index:

• 1.5L Toyota Tercel Index of Articles.

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

• How To Test The Starter Motor (1993-1998 1.5L Toyota Tercel).
• How To Test For A Blown Head Gasket (1991-1998 1.5L Toyota Tercel).
• How To Test Engine Compression (1991-1998 1.5L Toyota Tercel).
• How To Test The Igniter (1997-1998 1.5L Toyota Tercel).