Problems with your Forester Ignition Coil can cause serious issues with your 2.5 liter Subaru engine. Some of these Subaru Forester problems can range from intermittent engine misfire issues or your Forester not starting. This coil pack is mounted to the top of your engine, and failure of these coils are relatively common.
Today I’ll be showing you how to test the Forester ignition coil in your 2000 Subaru. To do this however you’ll need a digital multimeter to measure resistance of the coils. If you have misfire make sure that you check your crank and cam angle sensors before continuing onto your Subaru coil pack.
When your Forester has an issue with the coilpack, chances are the check engine light will lit up. When you see this check engine symbol on your dashboard, you’ll need the right scan tool to pull your code.
If you determine that your OBDII trouble code is ignition coil related, this guide is for you.
While you are testing your Forester ignition coil you should also inspect your spark plugs and spark plug wires. If you see any issues with these components, replace them right away.
Symptoms of a bad Forester ignition coil
Because this ignition coil pack is mounted to the top of your boxer engine failure is fairly common. Exposed to the heat and vibration in your engine bay, this procedure can help you test the coil packs. Here’s a few of the other Subaru Forester issues that might come up from failed spark plug coils.
- Poor performance
- Black smoke from exhaust
- Failed emissions test
- Engine misfire
- Check Engine Light ON
Testing your Forester ignition coil pack
To begin our comprehensive ignition testing guide, you’ll begin by testing the coil pack internal resistance. There’s two ways to go about this. First open your hood and locate the coil pack. Unplug your Forester ignition coil pack.
Once you’ve disconnected the four wire pin connector, you will be using your multimeter to measure resistance. You do this at the four wire connector at the face of your coil packs.
Place the leads of your multimeter to PIN A and PIN B. You should have 0.73 Ω ± 10% between these two pins on the Forester ignition coil.
Now check PIN C and PIN D and the measurement should read the same. If your resistance reads below this mark, it’s a sign of an open condition or a short in your Subaru ignition coil packs.
Now that you’ve tested for internal resistance at the terminal pins, you must also check the secondary resistance at the spark plug leads. These leads correspond to the Forester ignition coil terminals you just tested.
Testing for secondary resistance in coil pack
The next step of this DIY guide is to measure resistance at the spark plug wire terminals. Much like the wiring connector above, this is done in pairs using the Forester ignition coil diagram below. Crank your multimeter down a notch and probe at the pairs shown to measure secondary resistance.
The resistance at these spark plug coil pairs should read 12.8 kΩ ± 15% for either pair. If any of the measurements of your Forester ignition coils do not match these specifications, it’s a sign your coil has gone bad. Remove the four bolts that hold this coil pack in place, and install your replacement coil pack.
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