Testing the igniter (ignition control module) in the 1993-1995 1.6L 4A-FE Toyota Corolla, to see if it's failed and causing an engine no-start, isn't difficult at all.
I'll walk you through my method of testing the igniter to check if it's doing its job. The best part? This is an on-car test.
Contents of this tutorial:
- Symptoms Of A Bad Igniter.
- Distributor Connector Circuit Descriptions.
- How the Igniter Works.
- TEST 1: Making Sure The Igniter Is Getting Power.
- TEST 2: Making Sure The Igniter Is Getting Ground.
- TEST 3: Testing The Igniter Control Signal.
- TEST 4: Testing The Ignition Coil Activation Signal.
- More 1.6L Toyota Corolla Tutorials.
APPLIES TO: This tutorial applies to the following vehicles:
- 1.6L 4A-FE Toyota Corolla: 1993, 1994, 1995.
IMPORTANT: Before testing the igniter, check the ignition coil for spark first.
If you've got spark from even just one spark plug wire, the igniter's working fine and you don't need to go any further. If you haven't tested the ignition coil yet, this tutorial will help you do that:
Ignition System Wiring Diagrams:
Distributor Pickup Coil Tests:
Engine No-Start Diagnostics:
Other Igniter Test Tutorials:
- How To Test The Igniter (1989-1992 1.6L Toyota Corolla).
- How To Test The Igniter (1996-1997 1.6L Toyota Corolla).
Symptoms Of A Bad Igniter
The igniter (ignition control module), which is located in the distributor, plays a key role in the ignition system. It's one of the components that makes sure the engine has the spark necessary to start and stay running.
In a nutshell, the igniter works with the fuel injection computer to:
- Trigger the ignition coil by sending it (the ignition coil) activation signals.
- Control ignition timing by deciding when and how long the coil sparks.
- Tell the fuel injection computer when the engine's cranking or running, so it can turn on the fuel pump and injectors.
When the igniter fails, the ignition coil won't fire, when means that none of the spark plugs get spark. Plus, the fuel pump and injectors won't turn on. The end result is an engine that won't start since it's got neither spark nor fuel.
Distributor Connector Circuit Descriptions
You'll find the igniter inside the distributor, right under the distributor cap. The distributor's got two connectors —one with two wires and another with six wires.
Each wire has its own job, and here's a quick rundown of what they do:
2-Wire Connector:
| Pin | Wire Color | Description |
|---|---|---|
| 1 | Black with orange stripe (BLK/ORG) | B+ → Ignition 12 Volts |
| 2 | Black (BLK) | IG- → Tachometer Signal |
6-Wire Connector:
| Pin | Wire Color | Description |
|---|---|---|
| 1 | Black (BLK) | IGT → Ignition Timing Signal |
| 2 | White (WHT) | NE- → Sensor Ground For NE Signal |
| 3 | Green (GRN) | G- → Sensor Ground For G1 Signal |
| 4 | Black with yellow stripe (BLK/YEL) | IGF → Ignition Feedback Signal |
| 5 | Black (BLK) | NE → Engine Speed Signal |
| 6 | Red (RED) | G1 → Crankshaft Position Signal |
NOTE: The distributor harness connector has female terminals, while the connector coming out of the distributor itself has male terminals.
How the Igniter Works
When you turn the key and crank your 1993-1995 1.6L Toyota Corolla's engine, a whole process kicks off to send spark to all four cylinders, start the engine, and keep it running.
Here's what happens:
- The igniter gets 10 to 12 Volts DC from the ignition switch.
- This power comes through the black with orange stripe (BLK/ORG) wire on the distributor's 2-wire connector, which also powers the ignition coil.
- As the engine cranks, the pickup coil inside the distributor generates the G1 and NE signals and sends them straight to the fuel injection computer.
- Once the ECM gets both signals, it sends an IGT (Ignition Timing) signal to the igniter.
- The IGT signal tells the igniter when to fire the ignition coil.
- This signal travels through the black (BLK) wire, which connects to terminal number 1 on the distributor's 6-wire connector.
- After receiving the IGT signal, the igniter sends out the +B2 activation signal to the ignition coil.
- The +B2 signal makes the ignition coil fire spark.
- Once the ignition coil fires, the igniter sends an IGF (Ignition Feedback) signal back to the fuel injection computer.
- The IGF confirms the ignition coil fired, allowing the fuel injection computer to activate the fuel pump and injectors.
Now that you know how it all works, let's get to testing.
TEST 1: Making Sure The Igniter Is Getting Power
IMPORTANT: If the ignition coil is firing spark and sending it to all four cylinders, then the igniter's working fine. So before testing the igniter, make sure you've checked for spark first:
The first we're gonna do, to get our igniter diagnostic started, is use a multimeter to check if the igniter's getting power (10 to 12 Volts DC).
This voltage reaches the igniter through the black with orange stripe (BLK/ORG) wire, which connects to terminal number 1 on the distributor's 2-wire connector (see the illustration above).
Once we confirm the igniter's getting power, we'll move on to TEST 2.
Here's how to test it:
- 1
Unplug the distributor's 2-wire electrical connector.
- 2
Attach the black multimeter test lead to the battery's negative (-) terminal.
- 3
Have your helper switch the key to the ON position.
- 4
Set your multimeter to Volts DC mode.
- 5
Lightly probe female terminal number 1 (on the 2-wire connector) with the red multimeter test lead.
NOTE: Make sure female terminal number 1 on the 2-wire connector corresponds to the BLK/ORG wire. - 6
Your multimeter should show 10 to 12 Volts DC.
Here's what your test results mean:
CASE 1: Terminal 1's voltage is between 10 and 12 Volts. That's exactly what you're supposed to see.
Now, let's check if the igniter's got Ground. To do that, head over to: TEST 2: Making Sure The Igniter Is Getting Ground.
CASE 2: Terminal 1 isn't getting the indicated voltage. That means the igniter isn't working 'cause it's not getting battery power.
Your next step is to figure out why that power's missing and fix it. Once battery power is back (to the BLK/ORG wire), the igniter should start working again.
TEST 2: Making Sure The Igniter Is Getting Ground
Now that TEST 1 shows the igniter's getting power, the next thing to check is if it's got a solid connection to Ground.
Unlike other engine management components that have their own Ground wire, The igniter gets Ground straight through its metal case.
As you're already aware, the igniter is bolted to the distributor with two screws, and since the distributor's attached to the cylinder head, that creates a direct path (connection) to chassis Ground.
To see if it's grounded, we're just gonna check for continuity between the igniter's case and the battery's negative (-) post.
If it's grounded right, the multimeter should show continuity.
Alright, let's do this:
- 1
Disconnect the battery's positive (+) cable from the battery positive (+) post.
NOTE: Keep the battery's negative (-) cable connected to the negative (-) post. - 2
Take off the distributor cap.
- 3
Switch your multimeter to Ohms (Ω) mode.
- 4
Touch one multimeter lead to the igniter's metal case.
- 5
Touch the other lead to the center of the battery's negative (-) post.
- 6
The multimeter should show continuity.
If you see continuity (anything under 1 Ohm), the igniter's grounded properly.
If there's no continuity (infinite resistance or OL on the display), the igniter isn't grounded.
Here's what your test results mean:
CASE 1: The igniter's got continuity to Ground. That's exactly what you're supposed to see.
Now, let's check if the igniter's getting the IGT signal from the fuel injection computer. Head over to: TEST 3: Testing The Igniter Control Signal.
CASE 2: The igniter DOES NOT have continuity to Ground. This usually means there's corrosion or a bad connection between the igniter's case and where it's mounted.
Check the mounting points and clean 'em up to make sure there's solid metal-to-metal contact. Once the case is grounded right, the igniter should work like it's supposed to.