This tutorial will help you to diagnose a BAD ignition module vw control(ICM) causing a Misfire Condition on your VW 1.8L Passat (New Beetle, Jetta, Golf) . It will also help you to troubleshoot a BAD Coil-On-Plug (COP) Ignition Coil.
Ignition Module vw
One of the most common failures with this type of ignition control module (ICM) is a Misfire Condition in which the Ignition Module doesn’t activate one of the Coil-On-Plug (COP) Ignition Coils.
This condition is usually misdiagnosed as a BAD Ignition Coil and the end result is money spent on parts that don’t solve the misfire issue.
In this article, I’ll show you my way of testing the ignition control module. It’s a very easy test, that doesn’t involve using any expensive diagnostic equipment (not even a scan tool!) and that I’ve used time and time again, over the years, with very accurate results.
For your cross reference information, the Ignition Control Module that this article covers are:
AutoZone part #:Duralast RB155O’Reilly part #:MasterPro 2-7122Import Direct 14-0284Import Direct 14-0279AC Delco F1909AOthers:STANDARD MOTOR PRODUCTS Part # LX920Airtex Part # 6H1022WELLS Part # RB155
What Tools Do I Need To Test The Ignition Control Module And The COP Coils
As I mentioned at the beginning of this tutorial, you don’t need a scan tool. Here are the tools you’ll need:
MultimeterA digital or analog multimeter will work.If you need to buy one or are looking to upgrade, check out my recommendations here: Buying A Digital Multimeter for Automotive Diagnostic Testing.A Spark TesterA dedicated spark tester is a must have tool to correctly diagnose an Ignition System Misfire or No Spark Condition. I’m gonna’ recommend to you the HEI Spark Tester because of its accuracy and ease of use. To find out more about this Spark Tester, you can read more here: HEI Spark Tester.Wire Piercing ProbeAlthough not an absolute must, this tool is a time saver of the first order. To see what this tool looks like, click here:Wire Piercing Probe.
You’ll also need basic hand tools to remove the Ignition Module (if it tests BAD that is), like a ratchet wrench, sockets, etc.
Ignition Module Circuit Descriptions

The Ignition Control Module has two connectors. Looking down at the Ignition Module (with the Ignition Module still bolted in place), you’ll notice that the ignition control module has a left connector and a right connector.
In the Pin Out charts below is a brief job description of what each wire does.
NOTE: Although I’ve included the color of the wires, in the charts below, I can tell you that they are not gonna’ match the colors that are on your vehicle (it’s been my experience that the colors described on the wiring diagrams usually never matches what’s on the VW).
So then, how can you locate the wire you’ll need to test? Very easily, because the connector labeled as the ‘Left Connector’ (in the photo above) has only 4 wires connected to it and the connector labeled as the ‘Right Connector’ has 5 wires connecting to it.
Also, you’ll find the number of the wire embossed on the Ignition Control Module (Igniter) and this will also help you further identify the wire to be tested.
Right ICM Connector Pin outsPinWire ColorDescription1Gray *Cyl. #1 Ignition Coil Signal2Gray w/ Brown stripe *Cyl. #2 Ignition Coil Signal3Gray w/ Black stripe *Cyl. #3 Ignition Coil Signal4Brown w/ Black stripe *Cyl. #14 Ignition Coil Signal
* Your specific VW vehicle may have different colors.
Left ICM Connector Pin outPinWire ColorDescription1Grey w/ Yellow stripe *To Fuel Injection Computer2Yellow w/ Grey stripe *To Fuel Injection Computer3Brown *Chassis Ground4Red w/ Gray stripe *To Fuel Injection Computer5Green w/ White stripe *To Fuel Injection Computer
* Your specific VW vehicle may have different colors.
COP Ignition Coil Circuit Descriptions

OK, before we jump into the testing part (in the next page), you need to know a few more things and this is what each of the three wires that connect to the ignition coil connector do.
This is important because in the tests (in this tutorial), I’m gonna’ ask you to verify Power (12 Volts), Ground and continuity between the ICM and Coil at the ignition coil’s 3-wire electrical connector.
OK, these are the circuits (wires):
COP Ignition Coil Connector Pin outsPinWire ColorDescription1Color will vary with Coil *ICM Switching Signal2Brown w/ Yellow stripe *Chassis Ground3Black w/ Blue stripe *Power -12 Volts
* Your specific VW vehicle may have different colors.
Once again, I want to tell you that you don’t have to worry about the specific colors of the wires on your vehicle since you’ll be able to located the correct wire to test with the photo I’m providing.
OK, let’s turn the page and get testing!