P0301 Honda 3.5L – How To Test Coil On Ignition

The P0301 Honda OBDII trouble code means that your Honda or Acura 3.5L engine is misfiring in cylinder 1. This can cause your V6 engine to respond poorly and feel sluggish to accelerate. Engine cylinder misfire can lead to problems with your engine and catalytic converter, so it’s wise to address it immediately. Other codes may exist from P0301, P0302, P0303 and so forth to represent the engine cylinder that is misfiring. I’ll be showing you how to test this in a 2000 Honda Odyssey with a 3.5L J35A1 engine with coil-on plug style ignition. Before we begin on how to test this on your vehicle, let’s take a look at what is causing the P0301 Honda OBDII trouble code.

What is coil-on plug?

Coil-on plug technology eliminates the need for ignition wires as the coils are placed directly on or atop the spark plug for maximum spark performance. Most of these late model coil-on systems are three wire units. I’ll be showing you what wire does what and how to test each wire directly.

Symptoms of a bad COP ignition coil can range from rough idle, poor fuel economy and sluggish acceleration. In extreme cases it can prevent your vehicle from starting.

How to Test a Honda 3.0 3.5L J Series Ignition Coil

We’ll begin the how to test coil on ignition coils by removing the 10mm bolts that hold the upper J series engine cover in place.



There are four 10mm deep bolts that run through this plastic shroud and into your intake manifold.


After these are removed, use a standard flathead screwdriver to undo the plastic front rivets on the lower engine cover.


After removing both plastic tabs pull up on the lower cover to remove.


Next remove the upper cover to expose your intake manifold and igntion coils.


We’ll be testing and removing the cylinder 1 which is located in the front of the vehicle.


Unplug the three-pin connector to take a look at the wires you will be back pinning and testing.


The pins above are

The most common symptoms of a BAD Coil-on-Plug Ignition Coil or Coil-on-Plug Ignition System faults are:


You will be splicing open the protective layer that covers these three wires for better exposure, and then plugging it back into your ignition coil.

Checking for Ignition Coil Power


Using a voltmeter or similar voltage reading device, measure pin 1 or the black wire with yellow stripe for a 12 volt condition with the key set to the “ON” position. The middle pin or the black wire is the ground, check for power here using a voltage reading device or connect the black to this wire with the red probe to your battery.

If you do not have power and ground here at these two wires, you have a break somewhere between the main ignition harness and your terminating ignition coil. Have your harness checked or rewire the harness itself.


Check Coil-On Ignition Coil Trigger Signal


If you have reached this point, you have confirmed power and ground to your igntion coil in question. Now you’ve got to check that your coil-on ignition coil has a trigger signal from the igniter. Because this engine is without a distributor, you may need to check your igniter if this test and your coil check out okay.

Backpin the last pin on your ignition coil using a paper clip if your voltage reading device does not have a piercing tip. Place the negative post of your voltmeter to this wire and put the voltmeter into Hertz mode (Hz).

Have a friend get into the car and ensure that the parking brake is on and that the car is not in gear. Now put the red post of your multimeter to the battery and you should see a fluctuating value of 30-60 Hz. This represents the trigger value being sent by your igniter in your distributorless J35 engine ignition system.

If you read this value upon the cranking state, this means that your coil-on ignition plug is dead and needs replacement. Undo the hex nut and replace the unit, which should allow you to reset your ECU and the check engine light.

If you do not see this value however there’s something else wrong with your ignition system. namely your ignitor or possibly another unrelated electrical issue.

Have any questions about your 3.5 liter VTEC engine or the P0301 Honda trouble code? Let me know below!

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