This tutorial will help you test the igniter (ignition control module) on the 1995 thru' 1996 1.5L Toyota Tercel.
You don't need any expensive diagnostic tools to follow the test instructions, since I'll be showing you how to test it using a simple LED light.
I've also included the Oscilloscope wave form patterns for the IGT control signals you'll need to see if you're using one.
Contents of this tutorial:
- Symptoms of Bad Igniter.
- Igniter Circuit Descriptions.
- Where To Buy The Igniter (Ignition Control Module).
- Basic Operation Theory Of The Igniter.
- TEST 1: Testing For Spark At All 4 Cylinders.
- TEST 2: Making Sure The Igniter Is Getting Power.
- TEST 3: Making Sure The Igniter Is Getting Ground.
- TEST 4: Testing The Igniter Control Signals.
- TEST 5: TEST 5: Testing The Ignition Coil Control Signals.
You can find this tutorial in Spanish here: Cómo Probar El Módulo De Encendido (1995-1996 1.5L Toyota Tercel) (at: autotecnico-online.com).
WIRING DIAGRAM: You can find the igniter wiring diagram here: Igniter Wiring Diagram 1995-1996 1.5L Toyota Tercel.
You can find the 1997-1998 Toyota Tercel igniter tests here:
Symptoms Of A Bad Igniter
The igniter (which is another name for the ignition control module) is the component that activates the ignition coils sitting on top of the engine's valve cover. When this bad boy fails, your Toyota Tercel is not gonna' start due to a lack of spark (at all four cylinders).
What gives away the igniter as defective, when testing it, is the fact that it's getting battery power, ground, and its two igniter control signals from the fuel injection computer but it does not activate the ignition coils to fire spark away.
Igniter Circuit Descriptions
The igniter (ignition control module) has 8 wires coming out of its connector. Each one has a specific job to do and here's a brief description of each:
|1995-1996 1.5L Tercel Igniter Connector
|Red with white stripe
|IGC2 -2/3 Ignition coil control signal
|Light green with black stripe
|IGF -Ignition coil firing feedback
|White with black stripe
|GND -Chassis Ground
|Blue with yellow stripe
|IGT2 -Igniter control signal cylinders 2/3
|IGT1 -Igniter control signal cylinders 1/4
|Black with blue stripe
|TACH -Tachometer signal
|Black with orange stripe
|+B -Battery power
|IGC1 -1/4 Ignition coil control signal
NOTE: The igniter harness connector has female metal terminals. You'll need to use a back probe or a wiring piercing probe to test the signals in the wires.
Where To Buy The Igniter (Ignition Control Module)
Yup, this bad boy is very expensive. Check out the following links and comparison shop:
Basic Operation Theory Of The Igniter
In a nutshell, when you turn the key and crank the engine:
- The igniter gets battery power on the igniter harness connector terminal #7 (see illustration above).
- The wire that feeds battery power to the igniter is the black with orange stripe (BLK/ORG) wire.
- This same circuit also feeds battery power to the ignition coils.
- The crankshaft and camshaft position sensors start to generate their signals. These signals are transmitted directly to the fuel injection computer.
- Once the fuel injection computer gets the crank and cam position signals, it sends two igniter (IGT) control signals to the igniter. The IGT signals are what tell the igniter to start activating the ignition coils.
- The signal to activate the 1/4 ignition coil is received on terminal #5. The color of the wire is light green (LT GRN). This circuit is labeled as IGT1
- The signal to activate the 2/3 ignition coil is received on terminal #4. The color of the wire is blue w/ yellow stripe (BLU/YEL). This circuit is labeled as IGT2
- When the igniter receives the igniter control signals, it now activates the ignition coils by switching the ignition coils' primary circuits ON and OFF:
- Ignition coil for cylinders 1/4 is activated thru' the red (RED) wire. This circuit is known as the IGC1 circuit.
- Ignition coil for cylinders 2/3 is activated thru' the red with white stripe (RED/WHT) wire. This circuit is known as the IGC2 circuit.
- Once the ignition coils get their IGC1 and IGC2 signals, they start to spark away.