You can easily and quickly test the ignition coils on your 2.8L Chevrolet Colorado or GMC Canyon without fancy or expensive diagnostic equipment.
In this tutorial, I'll explain how to test them step by step. You'll quickly find out if an ignition coil is bad and causing an engine cylinder misfire problem.
Contents of this tutorial:
- Symptoms Of A Bad Ignition Coil.
- Ignition Coil Pin Outs.
- Where To Buy The Ignition Coil And Save.
- TEST 1: Testing The Ignition Coil For Spark.
- TEST 2: Making Sure The Ignition Coil Is Getting Power.
- TEST 3: Making Sure The Ignition Coil Is Getting Ground.
- TEST 4: Swapping The Ignition Coils.
- Other Common Misfire Causes.
- More 2.8L Chevrolet Colorado (GMC Canyon) Tutorials.
You can find this tutorial in Spanish here: Cómo Probar Las Bobinas De Encendido (2004-2006 2.8L Chevrolet Colorado, GMC Canyon) (at: autotecnico-online.com).
APPLIES TO: This tutorial applies to the following vehicles:
- 2.8L Chevrolet Colorado: 2004, 2005, 2006.
- 2.8L GMC Canyon: 2004, 2005, 2006.
NOTE: You can find the ignition system wiring diagram here: Ignition System Wiring Diagram (2002-2005 2.8L Chevrolet TrailBlazer).
Symptoms Of A Bad Ignition Coil
As you're already aware, the ignition coil's job is to supply spark to its cylinder. This spark then ignites the air-fuel mixture within the cylinder.
If spark goes missing, the cylinder does not produce power and is considered 'dead' (misfiring).
The fuel injection computer will notice the misfire and set a misfire diagnostic trouble code. It'll also illuminate the check engine light.
You'll see one or more of the following diagnostic trouble codes registered in the PCM's memory:
- P0300: Random Cylinder Misfire.
- P0301: Cylinder #1 Misfire.
- P0302: Cylinder #2 Misfire.
- P0303: Cylinder #3 Misfire.
- P0304: Cylinder #4 Misfire.
Besides a misfire trouble code stored in your Chevrolet Colorado or GMC Canyon's fuel injection computer, you're going to see one or more of the following symptoms:
- Bad fuel mileage.
- The check engine light flashes when the misfire is occurring.
- Rough idle.
- Lack of power as you accelerate under load.
- Engine misses (misfires) as you accelerate it's under load.
- Smell of raw fuel coming out of the tailpipe.
Ignition Coil Pin Outs
| Ignition Coil -Cyl #1 | ||
|---|---|---|
| A | Pink (PNK) | 12 Volts |
| B | Purple (PPL) | Activation Signal |
| C | Black (BLK) | Chassis Ground |
| Ignition Coil -Cyl #2 | ||
|---|---|---|
| A | Pink (PNK) | 12 Volts |
| B | Red with white stripe (RED/WHT) | Activation Signal |
| C | Black (BLK) | Chassis Ground |
| Ignition Coil -Cyl #3 | ||
|---|---|---|
| A | Pink (PNK) | 12 Volts |
| B | Light Blue (LT BLU) | Activation Signal |
| C | Black (BLK) | Chassis Ground |
| Ignition Coil -Cyl #4 | ||
|---|---|---|
| A | Pink (PNK) | 12 Volts |
| B | Dark green with white stripe (DK GRN/WHT) | Activation Signal |
| C | Black (BLK) | Chassis Ground |
Where To Buy The Ignition Coil And Save
The following links will help you to comparison shop for the ignition coil. All of the links point to well-known automotive brand ignition coils (no knock-offs):
TEST 1: Testing The Ignition Coil For Spark
You'll test all four ignition coils for spark with a dedicated spark tester to get started.
Of course, you don't have to test all four ignition coils; you can test the one you suspect is bad.
If you don't know which one is the one (or ones) causing a misfire problem, I recommend that you test all four ignition coils.
IMPORTANT: To get the most accurate test result from your ignition coil test, you need to use a dedicated spark tester. If you don't have one and need to buy one, I recommend the HEI spark tester. You can see what this tool looks like and where to buy one here: The HEI Spark Tester (The Best Spark Tester On The Market).
These are the test steps:
- 1
Remove the ignition coil from its place on the valve cover.
- 2
Connect your spark tester to the ignition coil.
- 3
Reconnect the ignition coil to its electrical connector (if you disconnected it to remove it).
- 4
Ground the spark tester with a battery jump start cable directly on the battery negative (-) terminal.
- 5
Have a helper crank the engine while you observe the spark tester.
- 6
The spark tester will do one of two things: Spark or Not Spark.
Let's take a look at what your test results mean:
CASE 1: The spark tester sparked. This is the correct and expected test result.
This test result also confirms the ignition coil is good and that it is getting power, Ground, and an activation signal.
If the cylinder is misfiring, take a look at the following section for more testing suggestions: Other Common Misfire Causes.
CASE 2: The spark tester did not spark. This test result generally lets you know that the ignition coil (that is not sparking) is defective and needs to be replaced.
Before condemning the ignition coil as defective, make sure that it's getting power, Ground and an activation signal. Go to: TEST 2: Making Sure The Ignition Coil Is Getting Power.
