How To Test The GM Ignition Control Module (1995-2005)
Jul 11, · Testing an ignition coil simply involves removing it from its place on the engine valve cover and attaching a spark tester to it. Then the engine is cranked to see if the spark tester sparks. If the spark tester sparks, then you can conclude that the ignition coil is OK (not defective). Place one test lead from the ohms meter on the negative post and one on the positive post of the coil. it doesn't matter which lead goes on which post because you are measuring resistance, not amps or volts. The reading should be between and ohms. If it .
In this tutorial I'm going to explain how to test the ignition coils on the,and 4. Testing the ignition coils, to find out if you have a defective one, isn't hard and I'll explain how to test them to find out in a step-by-step ignotion.
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. So when an ignition coil fails the very first thing that you're going to notice is a misfire problem when the engine is running.
You're also going to see the check engine light lit up by a specific misfire trouble code. You'll see one or more of the following:. Besides a misfire trouble code stored in your Chevrolet Trailblazer or GMC Envoy's fuel injection computer you're going to see one or more of the following symptoms:.
If your test results indicate that an ignition coil is defective on your 4. I think you'll save a few bucks by buying it online:. Testing an ignition coil simply involves removing it from its place on the engine valve cover and attaching a spark tester to it.
Then the engine is cranked to see if the spark tester sparks. If the spark tester sparks, then you can conclude that the ignition coil is OK not defective. You can also conclude that it's not behind the dead cylinder's misfire problem. If the spark tester DOES NOT spark then you can conclude that the ignition coil is defective and behind the misfire problem although it's a good idea to make sure it's getting power and an activation signal.
If you don't have one and need to buy one then I recommend the HEI spark tester. Connect a spark tester to the ignition coil. Reconnect the ignition coil to its electrical connector if you disconnected it to remove it. Ground the spark tester with a battery jump start cable directly on the battery negative - hoa. CASE 1: The spark tester sparked.
This is the correct and expected test result and lets you know that the ignition coil ignitino you're testing is not defective. This is a test result also confirms that this specific ignition coil is getting power and an activation signal from the fuel injection computer.
CASE 2: The spark tester did not spark. This test result generelly 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 you need to make sure that it's getting power and an activation signal. Other than not meeting any of those 3 criteria, this was a fine article. This material how to download dragon saga not be reproduced without the author's consent.
As an Amazon Associate, I may earn a small commission from qualifying purchases ignitioj the Amazon product links from this website. Your purchase helps support my work in bringing you real diagnostic testing information to help you solve the problem on your vehicle.
How to have good smile Chrysler ro. Contents of this tutorial:. Applies To:. Chevrolet Vehicles:.
Jul 11, · If the PNK wire is feeding 10 to 12 Volts to the ignition coil then the next step is to make sure that the fuel injection computer is supplying an activation signal. These are the test steps: 1 Disconnect the ignition coil from its electrical connector. Apr 13, · The following ignition system circuit diagram may be of help: Ignition System Circuit Diagram ( Chevy/GMC Pick Up And SUV). Ignition Coil Circuit Descriptions. The ignition coil on your car or truck may have or may not have 3 wires coming out of it. Whether it does or doesn't doesn't matter, the info in this test article still applies. Test the coil with a multimeter. Disconnect the coil pack's electrical connector then remove the coil pack from your car's engine using a wrench. Set the ohmmeter/multimeter to ohms range then turn it on. Using a meter lead, attach the spark plug wire terminal to each coil.
This is one of the easiest GM ignition control modules to test. This article will take you step by step through the whole process of diagnosing and troubleshooting a bad ignition control module and ignition coil. If you're GM car or truck starts and runs, this article will not help you. Since so many things can cause your vehicle to not start like a bad fuel pump, etc. At the end of this tutorial I've included a list of other tutorials that will help you diagnose a Cranks but Does Not Start Condition in case it's not ignition system related.
Specifically, the ignition coil will not spark. For this particular reason and before you follow the test procedures in this tutorial , you need to verify that the ignition coil IS NOT sparking by connecting a spark tester directly on the ignition coil's tower and cranking the engine. This is a pretty easy test, but it must be done with a spark tester. In this scenario, your vehicle will start and run most of the time, but every now and then it won't.
If this is the case, you'll have to wait till the car or truck does not start to use the tests in this article. You don't need a whole lot of stuff, heck, you don't even need a scan tool tho' a scan tool is important to have, but not for this article! Here is what you're gonna' need to effectively use the information in this article:. Here is a little background information to help you diagnose the ignition control module ICM or the ignition coil.
In a nutshell, when your turn the key and start cranking the engine:. If everything is working properly, the engine will start. Now, the important thing to know is that the PCM controls the creation of spark from the get-go crank up and at all engine speeds thru' the ignition control module ICM. The really cool thing about this type of ignition system is that all of these signals IC Signal and the Switching Signal can be tested easily with some very simple tools.
The following links will help you comparison shop for the factory original ignition control module and ignition coil:. Not sure if the ignition system components above fit your particular GM vehicle? Don't worry, once you get to the site, they'll make sure they fits and if they don't, they'll find you the right ones.
The ignition control module ICM has 4 wires coming out of it. Below are the descriptions of what each circuit does. Each circuit is identified by a letter, and this is the same letter that you will find on the ignition module's connector. The ignition coil on your car or truck may have or may not have 3 wires coming out of it. Whether it does or doesn't doesn't matter, the info in this test article still applies. Each circuit is identified by a letter, and this is the same letter that you will find on the ignition coil's connector.
If you'd like to have access to a wiring diagram, ignition component connector pin-outs, and the entire testing procedure in one place, then take a look at the following diagnostic manuals in downloadable PDF format:. All of the information you need to diagnose a misfire or a no-start problem caused by the ignition coil, the ignition module, or the crankshaft position sensor.
It fascinates me. I sit and look at it for hours. This material may not be reproduced without the author's consent. As an Amazon Associate, I may earn a small commission from qualifying purchases from the Amazon product links from this website. Your purchase helps support my work in bringing you real diagnostic testing information to help you solve the problem on your vehicle.
Home Misc Index Chrysler 2. What Tools Do I Need? Here is what you're gonna' need to effectively use the information in this article: A multimeter don't have a digital multimeter? Need to buy one?
An LED Light. A 12 Volt test light. A helper to crank the engine. A Wire Piercing probe. This tool is a time saver. If you need to see what this tool looks like, click here: Wire Piercing Probe. Basic Operating Theory Here is a little background information to help you diagnose the ignition control module ICM or the ignition coil.
In a nutshell, when your turn the key and start cranking the engine: Power in the form of 12 Volts flows into the crankshaft position CKP sensor, the ignition control module ICM , the ignition coil.. On an oscilloscope, it produces a digital square waveform.
With this IC Signal , the ignition module starts to activate the ignition coil to start sparking with a Switching Signal. Diagnostic manual comes with: Wiring diagrams. Component pin outs. Connector pin outs. Firing orders.
Complete step-by-step testing instructions. The illustrations in the diagnostic manual are printer friendly! Ignition system component part numbers. Firing order.
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