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How to Replace Spark Plugs 10-15 Toyota Prius

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How to Replace Spark Plugs 10-15 Toyota Prius

Created on: 2018-04-10

How to repair, install, fix, change or replace old or defective spark plug wires on 10, 11, 12, 13, 14, 15 Toyota Prius.

  1. step 1 :Removing the Wiper Arms
    • Pry the cap off the driver side wiper arm stud
    • Remove the 14m nut from the stud
    • Pull the wiper arm off the stud
    • Open the hood
    • Remove the two 14mm mounting nuts from the passenger side wiper arm
    • Pull the wiper arm off the windshield
  2. step 2 :Removing the Cowl Cover
    • Pry off the two cowl corner trim pieces with a trim tool
    • Pry the two push clips out of each side of the cowl with a flat blade screwdriver
    • Release the clips along the front of the cowl
    • Lift the cowl up and out of the engine bay
  3. step 3 :Removing the Wiper Transmission
    • Unplug the wiper motor electrical connector
    • Unclip the wiring harness from the lower wiper cowl
    • Remove the four 10mm bolts from the wiper transmission
    • Pull the wiper transmission off the lower wiper cowl
  4. step 4 :Removing the Lower Cowl
    • Remove the three 10mm bolts from the lower cowl bracket
    • Remove the bracket from the cowl
    • Remove the nine 10mm bolts from the lower cowl
    • Pull the cowl out of the engine bay
  5. step 5 :Removing the Ignition Coils
    • Remove the plastic engine cover
    • Disconnect the wiring harnesses
    • Remove the 10mm bolt from the coil pack
    • Lift the coil pack up and out
  6. step 6 :Removing the Spark Plugs
    • Remove the spark plug with a spark plug socket
  7. step 7 :Installing the Spark Plugs
    • Press the spark plug to the spark plug socket
    • Tighten the spark plug by hand
    • Torque the spark plug to 15 foot-pounds
  8. step 8 :Installing the Ignition Coils
    • Insert the coil into place
    • Tighten the 10mm bolt to the coil
    • Connect the wiring harness
    • Press the engine cover on
  9. step 9 :Installing the Lower Cowl
    • Fold over the cowl wind guides
    • Slide the lower cowl into place
    • Insert the nine 10mm bolts into the cowl
    • Raise the cowl wind guides
    • Line up the support bracket on the cowl
    • Insert the three 10mm bolts into the support bracket
  10. step 10 :Installing the Wiper Transmission
    • Line up the wiper transmission
    • Insert the wiper transmission pin into the rubber grommet
    • Insert the four 10mm bolts into the wiper transmission
    • Plug in the wiper motor electrical connector
    • Clip the wiring harness to the lower wiper cowl
  11. step 11 :Installing the Cowl Cover
    • Slide the cowl under the windshield
    • Push in the clips along the front of the cowl
    • Insert the two push clips into each side of the cowl
    • Clip the corner trim piece onto each side of the cowl
  12. step 12 :Installing the Wiper Arms
    • Line up the passenger side wiper arm on the windshield
    • Fasten the two 14mm nuts onto the wiper arm
    • Line up the driver side wiper arm on its stud
    • Fasten the 14mm nut onto the stud
    • Push the cap onto the wiper stud
    • Close the hood

Tools needed for replacement

  • Ratchets & Related

    Socket Extensions

    Torque Wrench


  • Screwdrivers & Related

    Flat Blade Screwdriver

  • Sockets - Metric

    14mm Socket

    10mm Socket

  • Sockets - SAE

    9/16 Inch Socket

Installation Video
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Hi, I’m Mike from 1A Auto. We’ve been selling auto parts for over 30 years!

To remove the driver's side wiper arm you can leave the hood down. Use a small flat-bladed screwdriver and gently pry up on this plastic cap. Find the edge. Pull it off. There's a 14mm nut under here. It needs a 14mm socket extension and ratchet. Loosen this up. Take the nut off. We're going to lift up on the arm. And now, I'll wiggle it back and forth. It should come right off the wiper arm shaft.

To open the hood, we'll go inside and pull the release. Find the safety latch, release that. The prop rod is under the hood. It's got two positions. One position here and then a service position here. It opens further. The passenger side of the wiper arm has two mounting nuts. They're 14 mm, and I'm going to use a 14mm socket and ratchet again. Loosen that one up and loosen this one up. You might need to hold the wiper arm to get it off. It popped right off. Release the spring action of the wiper arm and lift off the windshield. Put it aside.

To remove the side corner trim, this will be same on both sides. Pry it up with a plastic prying tool. You can buy this at When it's up, you slide it out and put it aside. There's two push clips on both sides that need to be removed. You can use a small flat-bladed screwdriver to pry it up. Pull the clip out. If the center part comes out, that's okay. Just push it back in to reuse it.

The center cowl piece is clipped along the edges and then it slides up under the window glass. So we're going to unclip it and slide it out this way. You kind of go in underneath and push the clips in. That one's loose. You go in and find all the clips. It might be easier to use the plastic trim tool to push the clip in. Push it up. Then slide it from underneath the windshield. I think this one clipped back in. Yup, it did. Make sure these stay clipped out. Put that aside.

To unplug the wiper motor, the lock of the clip is underneath the bottom. Squeeze it up. Pull the connector off. It's wiring harness should be clipped into here. Somebody's had it apart before, so the clips are a little bit broken. But you'll have to pry this clip out of here. You'll have to either slide this off or cut the electrical tape. Be careful not to cut the wires. Somebody's already had this apart. It'll come off here. There should be a clip here. It's missing. And then there's this clip here. And we just get the wiring harness out of the way.

There's a 10mm bolt here, one here, and then one here and here that's holding the wiper transmission to the car. We'll use a 10mm socket extension and ratchet and remove these bolts. Then lift the wiper transmission out of the car. It's sitting on a stud just under here. So pull that off.

We need to remove the lower cowl panel. There's nine 10mm bolts holding it in place. We need to remove all these bolts and then slide it out of the engine compartment. Use a 10mm socket extension and ratchet. To get clearance, I'm going to remove this bracket. There's two 10mm bolts. Lift it out of the engine compartment. Flop these down and over by sub clearance. To remove the plastic engine cover, it just sits on a couple of ball studs that pull right up.

To remove the four coils, the exact same procedure. This one's pointed in slightly a different direction but it will be identical to these three. To unclip the coil connector, push in on the lock. Sometimes, if you push in on the connector it helps to release it. If the connector is sticky, you can spray some water displacement oil on there. It's not going to hurt anything. Hopefully, it will come apart.

These connectors get gummed up with dirt. Sometimes if you move them in and out, it helps to free them up. Push it on here. To wiggle it off, try to pull on the connector not the wires. There we go. Use a 10mm socket extension and ratchet to remove the 10mm bolt holding the coil pack to the head. Just slide in here. It just fits with this connector, and we have a valve timing solenoid. Break it free. Get the bolt out of here and put it aside. Rock the coil pack back and forth, and it'll come right out.

Use a 9/16th spark plug socket or a 14mm spark plug socket, they're both very close, to remove the spark plug from the engine. The spark plug socket has a special rubber grommet in it. It grabs onto the spark plugs. You can lift it out. To put in a new spark plug and spark plug socket so it won't fall out, put it down into the cylinder, and thread it in by hand. Long threads. Thread it down til it stops.

I'm going to use a torque wrench, and I'll torque the spark plugs to 15 foot-pounds. That'll be enough to crush the gasket that seals it and prevents any leaks. Once it clicks, you're all set. Repeat this for the other three cylinders. The procedure will be exactly the same. The socket stayed on the spark plug, so the extension was kind of weak. Just play with it a little bit. Should eventually come loose. It's just a rubber part that sticks on the end of the spark plug. There it is.

So, this spark plug socket’s a little bit loose on my extension, and I just don't want it to stay in the cylinder head after I install the spark plug. Cause it's getting stuck, so I'm going to take a little bit of electrical tape and just tape over the end. And that way it just stays together better.

Install this new coil the exact same way the old one came out. Push it over the spark plug. Reinstall the bolt that holds it in place. Thread it in by hand to a steel bolt or an aluminum valve cover. So you don't want to cross thread it. Use socket extension and ratchet to just tighten it up. Once I feel like it gets tight, I will stop. I don't want to break the bolt off or break the valve cover. I reconnect the connector. It clicks when it locks in place. And repeat this procedure for the other three.

Something just to be aware of before you do this last coil. Leave this wire, or leave this coil pack disconnected because the wire harness does go over the bolt that you need to access. So I'm going to leave it disconnected for now. I can remove this coil, and when I'm all set. I'll plug this one back in.

To put your plastic engine cover back on, these three rubber mounts, just push over these three robber ball studs. Line it up with the oil cap hole.

To get our lower part of the car panel, the steel piece, these little air guides are folded over so they'll fit under the windshield. Slide it into place. I'll start reinstalling the bolts. I'll just go along and start them all by hand and then I can come back with a socket and ratchet to tighten them all. We'll shut that door, snap it in place. When they get tight, I'll stop. Clip this little door back. Tighten this one up.

To reinstall the support bracket, so we'll tab it into there. It's bolt caught here first. Rinse all the wiper transmission. So this little pin here is going into this rubber grommet up here. Push it up into place. Push it into that rubber grommet. Oops. It wants to pop out, so let's see. I took it off and I'll push it onto here, and then we can hook it in this way, just like that. Line it up with the mounting holes. We've got our bolts. Get this one started. Start the other ones. Tighten these all up. When you feel them get tight, then I'll stop.

We're going to reinstall the harness for the wiper motor. So this clip is kind of broken but it does go in here. There's a missing clip here. You clip it back into place. This goes through this opening here. This is normally clipped into here. And then there's a final clip here. And then, of course, you plug it in. It's keyed, only go in one way. It'll click when it locks in place. So, the plastic upper cowl cover. It's got some little tabs here. They're going to slide underneath the windshield, the edge of it. And then clips in the front that will clip down onto the metal.

So to get it up into position, put it over the wiper arms and we're going to slide it up, push it along the edge, and slide it over the glass like that. And then it will clip down into place. Place your push clips. Do that for both sides. Clip these little corner pieces back in place. So that part will go underneath the windshield and these will clip into the plastic here. Slide them underneath, clip them in place. Do the same for both sides.

To put the passenger side wiper in place there was a little dust line here where the wiper blade was, so I'll use that as a reference point. Should be right about there. There's some spring tension to this pushing it back up. I'll install the nuts. I'll just tighten these down ‘til they get tight. I don't want to break off the studs off the wiper transmission.

I'll reinstall the driver's side wiper arm and blade. You could do this with the hood down or the hood up, it's all right. Just get it in place. Reinstall the nut. Tighten it up. When I feel like it's tight, I'll stop. I don't want to break this hood off. And I'll reinstall the cap. It just pushes into place.

Thanks for watching. Visit us at for quality auto parts, fast and free shipping, and the best customer service in the industry.

Tools needed for replacement:

    Ratchets & Related

  • Socket Extensions
  • Torque Wrench
  • Ratchet

  • Screwdrivers & Related

  • Flat Blade Screwdriver

  • Sockets - Metric

  • 14mm Socket
  • 10mm Socket

  • Sockets - SAE

  • 9/16 Inch Socket

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