Author Topic: Replacing coil connectors on Toyota vehicles --  (Read 100 times)

Offline goodfellow

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Replacing coil connectors on Toyota vehicles --
« on: May 14, 2024, 06:42:02 PM »
The old 2005 Highlander needed new plugs, and while I was in there I decided to replace the coil connector plugs at the same time. These connectors are notorious for breaking the hold down tabs. After many heat cycles these connectors get brittle and there no way to take them off the coil without damage. It's one of the few Toyota repair issues that crop up very frequently. The tabs on this car broke months ago, and even the old zip tie trick wouldn't work because the connector had crumbled in too many places.

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Long story short, you have to remove the intake plenum in order to get to the rear cylinder bank plugs. There are many youTube vids out there that do a great job at explaining this procedure. I've posted several times on the GG on how I removed this plenum and the pitfalls that occur along the way.

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To install a new plug. remove the white inner alignment clip. A small screwdriver inserted in the bottom slot and prying up will release the clip.

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Then take a small screwdriver and insert underneath the lip of the individual push pin plugs and pry up; that releases the plug from the clip. In my case as soon as I pried up, the entire plug crumbled into pieces. Pretty much all of the plugs broke into pieces as soon as the little push pin plugs were pried on.

IMPORTANT!! Don't forget to take note of the wire color code to make sure you insert each pin plug back into the proper position on the new connector.

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Take the new plug and insert each push pin plug back into its original position and listen for the "click" as each push pin plug is pushed home.
Insert the white alignment lock into the front of the new connector and it's a done deal.

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The entire job -- spark plugs, new connectors, and reinstalling the plenum took about three hours. I took my time -- I'm an old guy.

This is the broken pile of connectors I had left -- the would literally break into dust if you touched them. Amazing that they held up this long -- 20 years.
The plugs looked very good, but there was some wear and the gap had increased. After 80K miles on these plugs, it was time.

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Tomorrow I have to do the CAT on this car. Got the dreaded P0430 Bank 2 Efficiency code (it's a 3.3L V6), and no amount of CAT/Sensor cleaner will help this situation. Glad it's Bank 2 since it's right in the front of the car.

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« Last Edit: May 14, 2024, 10:13:59 PM by goodfellow »

Offline Lookin4_67GalaxieConv

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Re: Replacing coil connectors on Toyota vehicles --
« Reply #1 on: May 15, 2024, 12:15:07 AM »
How many miles on the old girl?
boop/bop/beep

Offline goodfellow

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Re: Replacing coil connectors on Toyota vehicles --
« Reply #2 on: May 15, 2024, 07:09:09 AM »
How many miles on the old girl?
Getting close to 165K Galaxie. It's my daughter's car, and her job requires her to visit clients throughout her workday. Hence it gets a lot of miles. Given the sorry state of new vehicle quality and complexity these days, this old Highlander is a keeper. She loves it, and it'll run another 100K miles easy.

While I have it, I'll do a fluid service on it as well.

Online muddy

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Re: Replacing coil connectors on Toyota vehicles --
« Reply #3 on: May 15, 2024, 06:51:32 PM »
Those connectors are notorious for that.

You mentioned CAT cleaning? What's your preferred method? Is it just a temporary fix?

Sent from my twisted mind of the mudman


Offline goodfellow

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Re: Replacing coil connectors on Toyota vehicles --
« Reply #4 on: May 15, 2024, 07:00:02 PM »
Those connectors are notorious for that.

You mentioned CAT cleaning? What's your preferred method? Is it just a temporary fix?

Sent from my twisted mind of the mudman



Temporary fix Tim. I used a bottle of CataClean as directed and it solved the problem temporarily. Experience has taught me that once you get a P0430 or P0420, the specific Cat (left or right bank) is on its last legs. You can keep cleaning it, but eventually the code returns and it will need to be replaced in the very near future. Better to just replace it, along with the upper and lower sensors.

Online muddy

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Re: Replacing coil connectors on Toyota vehicles --
« Reply #5 on: Today at 05:45:37 PM »
Those connectors are notorious for that.

You mentioned CAT cleaning? What's your preferred method? Is it just a temporary fix?

Sent from my twisted mind of the mudman



Temporary fix Tim. I used a bottle of CataClean as directed and it solved the problem temporarily. Experience has taught me that once you get a P0430 or P0420, the specific Cat (left or right bank) is on its last legs. You can keep cleaning it, but eventually the code returns and it will need to be replaced in the very near future. Better to just replace it, along with the upper and lower sensors.
Kinda figured. I have the code on my truck. Watching the voltage readings while it runs it's evident that the cat is failing or failed.

I'll have to bite the bullet and put a new one in sometime.

Sent from my twisted mind of the mudman