Are You Having Trouble With Your Jaguar's Ignition Coil?

Are You Having Trouble With Your Jaguar’s Ignition Coil?

Ignition coil troubles can ruin everything that’s good about owning a Jaguar. Instead of punchy acceleration, you’re left with lacklustre performance. Where once your car was reliable and sporty, it now struggles to start, or worst of all, your engine goes into limp mode. All these scenarios should make it clear that catching ignition coil trouble early is essential. Keep reading to learn more.

Different Types of Ignition Coil

Your standard ignition coil is your Jaguar's version of a transformer. Its sole job is to change low voltage energy produced by the battery into high voltage electricity which can be used by the spark plugs. A basic ignition coil is made up of the following key parts; an iron core, a primary winding, a secondary winding, and electrical connections. There are three main types of ignition coils:

Dual Spark Ignition Coil

This has two connections on the primary and secondary windings and is used in even cylinder engines.

Four Spark Ignition Coil

These feature in four-cylinder engines and have two primary windings and one secondary windings with two connections each.

Single Spark Ignition Coil

These are used in engines where one coil is assigned to each cylinder.

Causes of Ignition Coil Failure

The four leading causes of ignition coil failure experienced by Jaguar drivers are:

  • Short Circuits: Commonly caused by overheating.
  • Faulty Voltage Supply: This is caused by a voltage supply which is low due to bad wiring or weak battery.
  • Mechanical Damage: This is usually caused by road debris, collision, or catastrophic engine breakdown, which damages the ignition cables.
  • Faulty Contacts: This is commonly caused by humidity.

Symptoms of Ignition Coil Failure

When your Jaguar's ignition coils are failing, you are likely to experience the following symptoms:

  • engine struggles to start
  • frequent ignition misfires
  • sluggish acceleration
  • power loss
  • engine switches to limp mode
  • illumination of EML
  • generation of fault codes

Troubleshooting your Jaguar's Ignition Coils

If you have mechanical experience or are a Jaguar enthusiast, you may be interested in trying to troubleshoot your ignition coil troubles at home. If so, you can follow the guide below:

1. Use the Diagnostic Unit

Connect the diagnostic reader to the 16-pin OBD connector and carry out the following steps: Select program > Select vehicle > Select fuel type > Select model > Select function required > Select system > Start fault diagnostics

2. Read the Fault Memory

Your Jags’ onboard computer will have sent out specific fault codes which describe the specific nature of the problem.

3. Determine the Cause of the Fault

Prepare the relevant diagnostic tools, such as a multimeter. Find your vehicle's technical documents, and remove your engine cover.

4. Visually Check the Wiring

Before starting diagnostics, give the wiring a visual check. Look out for kinks, wear, and damage which could explain the problem.

5. Check Voltage Supply

Remove the ignition coil from its connectors and measure the voltage. When measuring, you’re looking for a reading that is over 10.5V.

6. Check the Primary Actuation of the Ignition Coil

To do this, you need to connect a diagnostic tester to the measurement module of the ignition coil and detach the plug connects form the injection valves and then start the engine. You’re looking for a clearly-identifiable signal.

7. Remove the Coil for Further Testing

If you’ve not got to the heart of the problem, you can next remove the coil.

8. Measure Resistance

Using a multimeter, you should now check the removed coil. You should measure both the primary and secondary windings.

9. Replace the Coil

When replacing the coil, be sure everything fits back correctly and that all connections are reattached.

10. Clear the Fault Memory

If your investigations have triggered further fault codes, then you need to make sure to clear them before undergoing test drives.

11. Test Drive

Undergo a test drive with the diagnostic unit still connected. When this is complete, you can read out the fault memory again to check if your problem is resolved.

For Less Hassle, Choose Import Motorworx

If the diagnostic process listed above sounds like a lot of work, you can come to Import Motorworx where we will undertake the diagnostic work and any repairs necessary. We will consult you with our findings and present you with an affordable plan to get you back on the road safely and quickly. We happily service the communities of Lawndale, Culver City, West Los Angeles, and South Bay, CA. Stop by and say hello or give us a call to find out how we can help you maintain your Jaguar and keep it in top condition.

Written by Import MotorWorx