How To Test The Ignition Control Module (1990-1995 3.8L V6 Ford Taurus, Mercury Sable)

I think most folks are surprised by how easy it is to test the ignition control module (ICM) to see if it's behind an engine no-start.

The best part is you don't need to remove it from the engine compartment to check it. In this tutorial, I'm going to show you step by step how to do it with some very basic tools —no scan tool or expensive diagnostic equipment needed.

By the end, your test results will tell you whether the ICM's toast and needs to be replaced, or the issue lies somewhere else.

APPLIES TO: This tutorial applies to the following vehicles:

• 3.8L V6 Ford Taurus: 1990, 1991, 1992, 1993, 1994, 1995.
• 3.8L V6 Mercury Sable: 1990, 1991, 1992, 1993, 1994, 1995.

IGN SYSTEM WIRING DIAGRAMS:

• Ignition System Wiring Diagram (1990 3.8L V6 Ford Taurus, Mercury Sable).
• Ignition System Wiring Diagram (1991 3.8L V6 Ford Taurus, Mercury Sable).
• Ignition System Wiring Diagram (1992-1995 3.8L V6 Ford Taurus, Mercury Sable).

What Tools Do I Need To Test The Ignition Control Module?

To diagnose the ignition control module (ICM) as good or bad, you don't need any expensive or fancy diagnostic equipment. In the list below, you'll find the must-have tools you'll need to determine if the ICM on your Ford Taurus or Mercury Sable is bad or not:

• Multimeter: A multimeter will help you check that the ICM's getting power, and it can also be used to verify that it's receiving the PIP signal from the Profile Ignition Pickup sensor in the distributor. If you don't have one, or you're looking to upgrade the one you've got, this is the one I recommend: Tekpower TP8268 AC/DC Auto/Manual Range Digital Multimeter (Amazon affiliate link).
• LED Light: An LED light comes in handy when testing the PIP signal with the engine cranking. You can use a multimeter to check the PIP signal, but to get an accurate result, you've got to turn the engine over by hand. With an LED light, you can visually see the signal —the light will flash ON and OFF as you crank the engine. If you don't have one, this is the one I recommend, and you can buy it here: Oznium Flush Mount 12V LED Light (Amazon affiliate link).
• 12V automotive test light: A regular 12V incandescent test light will help us check the ignition coil's activation signal in TEST 2. If you don't have one, this is the one I recommend —you can see it here: Lisle 28400 Heavy Duty 12 Volt Test Light (Amazon affiliate link).

TEST 1: Making Sure The ICM Is Getting Power

To get our ignition control module (ICM) diagnostics underway, we're going to make sure it's getting power.

Power, in the form of battery voltage, is delivered to the ICM through the red with light green stripe (RED/LT GRN) wire. This wire connects to female terminal 3 of the ignition module's 6-wire connector.

These 10 to 12 Volts are available with the key in either the RUN or START position. For our test, we'll check for this voltage with the key in the RUN position and the engine OFF.

These are the test steps:

1. 1

   Disconnect the ICM from its 6-wire connector.

2. 2

   Place your multimeter Volts DC mode.

3. 3

   Connect the black multimeter test lead to the battery negative (-) post.

4. 4

   Turn the key to the ON position but don't start the engine.

5. 5

   With the red multimeter test lead, probe female terminal 3 of the connector.
   
   NOTE: Double-check that terminal 3 corresponds to the RED/LT GRN wire.

6. 6

   Your multimeter should read 10 to 12 Volts DC.

Let's interpret your test result:

CASE 1: Terminal 3 has 10 to 12 Volts present. This test result lets us know the ignition control module (ICM) is getting the power it needs.

Now we need to move on to our next test —making sure the ICM is activating the ignition coil. For this test, head to: TEST 2: Checking The Ignition Coil Activation Signal.

CASE 2: Terminal 3 doesn't have the indicated voltage. Without power, the ICM isn't going to function. With this result, we can rule out the ICM itself as the cause of the engine's no-start problem.

Your next step is to find out why the RED/LT GRN wire isn't delivering battery voltage with the key in the RUN position. Once you've restored power to the circuit, the ignition module should function, and the engine should start.

TEST 2: Checking The Ignition Coil Activation Signal

There's a good chance you've already tested and confirmed that the ignition coil activation signal isn't being sent from the ICM to the ignition coil. Still, I recommend checking it one more time —just to make sure we're dotting our I's and crossing our T's.

We're going to perform the ignition coil activation test right at the ignition coil's connector. The wire that delivers the activation signal to the ignition coil is the tan with yellow stripe (TAN/YEL) wire of the ignition coil connector.

It's important that you use a 12-Volt incandescent automotive test light to check for the presence of this signal. If you don't have one and need to buy one, this is the one I use and recommend: Lisle 28400 Heavy Duty 12 Volt Test Light (Amazon affiliate link).

CAUTION: You'll be working around a cranking engine. Keep your hands, tools, loose clothing, and test leads clear of moving engine parts such as belts and pulleys. Secure any long hair and avoid leaning over the engine while performing the test. Always stay alert and aware of your surroundings when working near moving components.

Alright, let's get to work:

1. 1

   Disconnect the ignition coil from its electrical connector.

2. 2

   Connect the test light's crocodile clip to the battery positive (+) terminal.

3. 3

   With the metal point of the 12 Volt test light, back-probe terminal 1 of the connector.
   
   The TAN/YEL wire connects to terminal 1 of the connector (see the connector pinout illustration above) and connects directly to the ignition control module.

4. 4

   Have your helper crank the engine while you observe the 12 Volt test light.

5. 5

   You'll see one of two things:
   
   1.) The 12 Volt test light flashes ON and OFF.
   
   2.) The 12 Volt test light DOES NOT flash ON and OFF.
   
   NOTE: Don't worry about what the test light does before cranking the engine. What matters is whether the test light flashes ON and OFF while the engine's being cranked.

Let's walk through what this result indicates:

CASE 1: The 12V test light did not flash ON and OFF while cranking the engine. This confirms the ICM isn't activating the ignition coil to fire spark.

Now that we've confirmed the ignition coil isn't getting an activation signal, our next step is to check that the ICM's receiving the Profile Ignition Pickup (PIP) signal from the distributor.

There are two ways to test the Profile Ignition Pickup (PIP) signal. One is with a multimeter and the other is with an LED light:

• TEST 3: Testing The PIP Signal With A Multimeter.
• TEST 4: Testing The PIP Signal With An LED Light.

NOTE: The difference between these two tests is in how the engine is cranked. If you use a multimeter to check the PIP signal, you'll need to turn the engine over by hand using a 1/2-inch ratchet and socket on the crankshaft pulley. Testing the PIP signal with an LED light, on the other hand, requires cranking the engine with the starter motor. Both methods are effective —the multimeter test is just a bit more involved.

CASE 2: The test light flashed ON and OFF. This confirms the ignition control module is actively trying to get the ignition coil to spark -meaning the ICM is not defective.

This test result also lets you know that the profile ignition pickup (PIP) sensor inside the distributor is OK. If the PIP sensor were bad, it wouldn't be generating its signal —and the ICM wouldn't be actively trying to trigger the ignition coil to spark.

If the engine isn't starting, it's not due to the ignition control module (or PIP sensor). Have you tested the ignition coil? Have you done any other ignition system tests? If not, the following tutorial will help you out: Ignition Coil And Basic Ignition System Tests (1990-1995 3.8L V6 Ford Taurus, Mercury Sable).

TEST 3: Testing The PIP Signal With A Multimeter

The PIP sensor, located inside the distributor, is the ignition system's de facto crankshaft position sensor. As the engine cranks or runs, it produces an ON/OFF voltage pulse that the ICM uses to begin activating the ignition coil to create spark.

We can easily check the ON/OFF voltage pulses the PIP sensor generates by tapping into the wire that connects to terminal 6 of the ICM's 6-wire connector.

• ON: PIP signal voltage is above 8 Volts DC.
• OFF: PIP signal voltage is below 2 Volts DC.

Depending on the specific year of your 3.8L V6 Ford Taurus or Mercury Sable, the wire connected to terminal 6 of your ICM will be one of the following colors:

• 1990-1991: Dark blue (DK BLU).
• 1992-1995: Gray with orange stripe (GRY/ORG).

To check the PIP signal with a multimeter, you'll need to manually crank the engine by hand. This involves raising the front of the vehicle, removing the passenger-side tire, the water splash shield (covering the crankshaft pulley and serpentine belt) and using a 1/2-inch ratchet and the appropriate socket on the crankshaft pulley bolt to turn the engine.

In case you're wondering, you can't use the starter motor to crank the engine for this test —only by turning the engine by hand can you clearly see the ON/OFF voltage pulses of the PIP signal.

If you prefer to test the signal with the engine actually cranking (with the starter motor), head over to TEST 4, which covers testing the PIP signal with an LED light.

CAUTION: You'll be working around a cranking engine. Keep your hands, tools, loose clothing, and test leads clear of moving engine parts such as belts and pulleys. Secure any long hair and avoid leaning over the engine while performing the test. Always stay alert and aware of your surroundings when working near moving components.

All right, let's get going.

1. 1

   Raise the front right side of your vehicle and place it on jack stands.
   
   IMPORTANT: NEVER trust the jack alone to keep the vehicle raised. ALWAYS use jack stands.

2. 2

   Remove the front right tire and the water splash shield that is covering the crankshaft pulley.

3. 3

   Disconnect the ignition coil from its electrical connector.
   
   NOTE: This is an important safety precaution —do not continue to the next step without doing this first.

4. 4

   Disconnect the ICM from its 6-wire connector.

5. 5

   Set your multimeter to Volts DC mode.

6. 6

   Connect the black multimeter test lead to the battery negative (-) terminal.

7. 7

   Connect the red multimeter test lead to the PIP signal wire, using the appropriate tool.
   
   The PIP signal wire connects to terminal 6 and will be either a DK BLU wire (1990-1991) or a GRY/ORG wire (1992-1995).

8. 8

   Turn the ignition key to the ON position, but don't start or crank the engine.

9. 9

   Slowly rotate the crankshaft pulley by hand using a 1/2-inch ratchet and the appropriate socket.
   
   NOTE: Rotate the pulley at least two full revolutions to ensure all of the tone wheel slots pass by the Hall effect sensor.

10. 10

    Watch your multimeter for voltage changes. Voltage should toggle between ON and OFF voltage states as you turn the crankshaft pulley.
    
    ON: Voltage above 8 Volts DC.
    
    OFF: Voltage below 2 Volts DC.

OK, let's interpret your test results.

CASE 1: The multimeter toggled between ON and OFF voltage states as you turned the crankshaft pulley. This test result lets you know that the PIP sensor is working and sending a valid PIP signal to the ignition control module.

You can conclude that the ICM is toast and needs to be replaced if you've confirmed all of the following:

• All six spark plug wires are not sparking.
• The ignition coil is not sparking.
• The ICM is getting 10 to 12 Volts (TEST 1).
• The ICM is not activating the ignition coil to fire spark (TEST 2).
• In this test section, you've confirmed that the PIP sensor is supplying a PIP signal to the ICM.

CASE 2: The multimeter did not toggled between ON and OFF voltage states as you turned the crankshaft pulley. Without a PIP signal, the ignition control module won't activate the ignition coil to start sparking —and without spark, the engine won't start.

Your next step is to check the PIP sensor. Checking the PIP sensor —which is located in the distributor— isn't difficult at all. I'll show you how, step by step, in this tutorial: How To Test The PIP Sensor (1990-1995 3.8L V6 Ford Taurus, Mercury Sable).

TEST 4: Testing The PIP Signal With An LED Light

My go-to method for checking the PIP signal is using an LED light —the cool thing being that I can crank the engine and visually see the ON/OFF pulses of the PIP signal with the LED light flashing ON and OFF.

I do want to point out that while using an LED light is effective, it's not as accurate as the multimeter method described in TEST 3. With the multimeter, you can actually see the peak voltage the PIP sensor is producing, which gives you a much clearer picture of its performance.

If you don't have an LED light to perform this test, this is the one I recommend and you can buy it here: Oznium Flush Mount 12V LED Light (Amazon affiliate link)

To check the PIP signal with the LED light, we're going to tap into the PIP signal wire. This is the wire that delivers the PIP signal to the ignition control module.

Depending on the year of your specific Ford Taurus or Mercury Sable, this wire will be one of the following colors:

• 1990-1991: Dark blue (DK BLU).
• 1992-1995: Gray with orange stripe (GRY/ORG).

Regardless of the wire color, the PIP signal wire is the one that connects to terminal 6 of the ignition control module connector. See the illustration above for the ICM pinout.

CAUTION: You'll be working around a cranking engine. Keep your hands, tools, loose clothing, and test leads clear of moving engine parts such as belts and pulleys. Secure any long hair and avoid leaning over the engine while performing the test. Always stay alert and aware of your surroundings when working near moving components.

This is what you need to do:

1. 1

   Disconnect the ignition coil from its electrical connector.
   
   NOTE: This is an important safety precaution —do not continue to the next step without doing this first.

2. 2

   Disconnect the ICM from its 6-wire connector.

3. 3

   Connect the red wire of the LED light to the battery positive (+) terminal.
   
   NOTE: You'll need to use a jumper wire to have the red lead of the LED reach the battery terminal.

4. 4

   Connect the black wire of the LED to the PIP signal wire, using the appropriate tool.
   
   The PIP signal wire connects to terminal 6 and will be either a DK BLU wire (1990-1991) or a GRY/ORG wire (1992-1995).

5. 5

   When all is set up, crank the engine.

6. 6

   The LED light should flash ON and OFF as the engine cranks if the PIP signal is being generated and sent to the ICM.

OK, let's interpret your test results.

CASE 1: The LED light flashed ON and OFF as the engine was cranking. This confirms the PIP sensor is doing its job —generating its signal and sending it to the ICM.

You can conclude that the ignition control module is fried and needs to be replaced if you've checked and confirmed all of the following:

• The spark plug wires are not delivering spark to the spark plugs.
• The ignition coil does not spark.
• The ICM is getting 10 to 12 Volts (TEST 1).
• The ICM is not generating an ignition coil activation signal (TEST 2).
• In this test section, the PIP sensor is confirmed to be generating and sending a PIP signal to the ICM.

CASE 2: The LED light did not flash ON and OFF as you cranked the engine. This confirms the Profile Ignition Pickup sensor isn't creating a PIP signal —and without it, the ignition control module isn't going to activate the ignition coil to spark and get the engine started.

Your next step is to check the PIP sensor itself to see if it's getting power and Ground. For this test, head over to the step-by-step tutorial on how to test the PIP sensor: How To Test The PIP Sensor (1990-1995 3.8L V6 Ford Taurus, Mercury Sable).

More 3.8L V6 Ford Taurus Diagnostic Tutorials

You can find a complete list of diagnostics tutorials for the 3.8L V6 Taurus and Mercury Sable in this index:

• 3.8L V6 Ford Taurus Index Of Articles.

Here's a small sample of the tutorials you'll find in the index:

• How To Test The TPS With A Multimeter (1990-1995 3.8L V6 Taurus, Mercury Sable).
• How To Test The Fuel Pump (1990-1995 3.8L V6 Ford Taurus, Mercury Sable).
• How To Test The MAF Sensor (1991-1995 3.8L V6 Ford Taurus, Mercury Sable).
• How To Test For A Blown Head Gasket (1990-1995 3.8L V6 Ford Taurus, Mercury Sable).