Tips to Identify Ignition Coil Failure in Your Volkswagen
by europewpadmin January 25, 2020Ignition coil failure in your Volkswagen can cause a variety of inconvenient symptoms such as rough idling and misfires. It can also contribute to further part failure, such as the premature wear of your spark plugs. Let’s take a closer look at the different kinds of ignition coil as well as why the coils may fail, what this means for your VW, and how to diagnose the issue.
The Different Types of Ignition Coils
A conventional ignition coil is, at heart, a mini-transformer. The job of the ignition coil is to convert low voltage electricity into high voltage electricity. The spark plugs use this to create sparks. Alongside its iron core, the ignition coil also features a primary and secondary winding as well as electrical connections. Here are the different types of ignition coils:
Dual Spark Ignition Coil
A dual spark ignition coil is used inside engines which have an even number of cylinders, such as a V8. Unlike a basic ignition coil, dual spark coils have two connections on their primary and secondary windings.
Four Spark Ignition Coils
Four spark ignition coils feature in four-cylinder engines. Like the dual spark coil, four spark coils have two primary windings which are triggered by an ECU unit. However, there is only one secondary winding. There are also two connections for spark plugs at each of the outputs.
Single Spark Ignition Coils
Single spark coils are used in systems where one coil has a primary and secondary winding assigned to each cylinder. Single spark ignition coils are installed at the cylinder head just above the spark plug.
The Causes of Ignition Coil Failure
There are four leading causes of ignition coil failure which are as follows:
1. Internal Short Circuits
Short circuits are caused when the coil overheats, which is commonly caused by age, faults in the module, or a faulty output stage in the ECU.
2. Voltage Supply Faults
Coil charging time will increase when the voltage supply is too low. This to premature wear or the ignition control unit becoming overloaded. This is commonly caused by a weak or aged battery or faulty wiring.
3. Mechanical Damage
Mechanical damage can occur when the ignition cables become damaged. This issue can also be caused by a failed valve cover gasket, with both of these issues ultimately leading to spark over and accelerated wear.
4. Contact Faults
Contact faults most commonly occur due to humidity. Risk of this can be caused by frequent engine washing or use of grit.
Signs of a Faulty Ignition Coil
Experiencing any of the symptoms listed below when driving your VW can indicate ignition coil failure.
- engine won’t start
- ignition misfires
- weak acceleration and noticeable power loss
- ECU switches engine to limp mode
- check engine warning light
- fault codes
How to Measure an Ignition Coil
If you are a mechanically savvy, you can check the function of your ignition coil. There are multiple ways in which you can do this.
If the coil is dismantled, use an ohmmeter. This tests the resistance values of the coil. You will want to consult with the manufacturer’s specifications to make sure your ignition coils sit within the correct range for your model of VW. If the reading is off, then you know you’ll need a new coil.
When the coil is installed, you can do a visual inspection and look for signs of mechanical damage. Check the housing of the ignition coil for hairline cracks or leaks. Check the wiring and plug connections for oxidation or corrosion, and finally, check for any visual signs of oil leaks. Use a multimeter/oscilloscope to check the voltage supply to the coil. Check the distributors triggering signal as well as the signals of the ignition control unit, or ECU. Use a diagnostic unit such as an OBD-II scanner to read the fault codes on the system to determine the parameters.
How European Auto Tech Can Help You
If you suspect your VW is suffering with 
an ignition coil problem and you don’t feel comfortable poking around under the hood, you can rely on European Auto Tech to resolve your issue quickly and affordably. Whether you live in any of the areas of Allen, Dallas, Flower Mound, Frisco, Highland Park, McKinney, Park Cities, Richardson, Southlake, University Park, Plano, TX, expert help is close at hand. Call us today or stop by to talk to one of our expert technicians.