Thursday, November 19, 2015

How to replace the alternator in a 1.8L Toyota Corolla, Yaris, Matrix, Scion xD and Pontiac Vibe

  This post covers removing and installing the alternator found on the 1.8L Toyota engine. This engine was used from 2009 to 2013 and is also found on the Yaris, Matrix, Scion xD and Pontiac Vibe. Shown is a 2010 Toyota Corolla. Due to it's location near the front of the engine compartment, working on it is not too difficult

                                                                The job at a glance
  • Tools: 10, 12 and 14mm 3/8" sockets and ratchet, breaker bar (optional), large Screwdriver 
  • Materials: none
  • Parts: Alternator  
  • Cost of parts:  $150-220
  • Time: 1 hour


1) Disconnect the battery with a 10mm wrench or socket and ratchet..

2) Remove the serpentine belt from the alternator. Loosen the upper 12mm and lower 14mm bolts on the alternator. Make note of the thread length on the tension adjuster for ease of returning the belt to proper tension. Loosen the nut in stages while turning the adjuster bolt counterclockwise to relieve all tension on the belt. Slip the belt off the alternator and let it rest below. It doesn't need to be fully removed unless being replaced. There is a separate post for the belt:

3) Unplug the lower control wire by depressing a keeper on the right side. Unwire the alternator. Use a small flat blade screwdriver to pry off the protective cover and slide it down the large B+ wire. Now use a 12mm socket to remove the nut. Remove the wire from the stud. Disconnect the wiring harness from the bracket to the left of the alternator.

3) Remove the upper 12mm mounting bolt.

4) Remove the lower alternator 14mm pivot bolt.

5) Remove the adjustment bracket above the alternator. This is a 12mm bolt. It is in the way of the removal of the alternator. 

6)  Remove the alternator. Use a large screwdriver under the alternator to pry it off the pivot arms. It will be removed up and out of the engine compartment. 


1) Slip the alternator through the top of the compartment and between the two pivot arms. It may be helpful to put a bit of grease on the mating surfaces of the arms as an aid as this is a tight fit.

2) Turn in the long 14mm pivot bolt hand tight only.

3) Install the adjustment bracket with the 12 mm bolt hand tight only.

4) Install the upper 12mm mounting bolt through the adjuster and into the alternator, again hand tight only.

5) Wire the alternator back up.

6) Install the belt in place. Refer to separate blog for that if needed.

7) Set the tension on the belt with the adjuster. Refer to measurement or guide used earlier or the rule of thumb: 1/2" of defection at the middle of the longest run of the belt.

8) Tighten all bolts to final torque.

9) Re-connect the battery.

10) Re-mount the engine cover.

11) Run and test. 



  1. See, this is one of the many reasons why I love JDM Cars - repairing them is a cinch! Well, most of the time anyway... But you wouldn't believe how much trouble it was to replace the alternator in my Cadillac Deville compared to this.

  2. Thank you thank you so much I finally got it out . Thanks to you . I started this 5 days ago and I just found your post . have a good day I will

  3. Just replaced my alt on my 2010 matrix. Now I'm having a HORRIBLE squeal from my belt. Could it be belt tension, maby bad alt. If anyone has any ideals I'm listening lol please n thank you

  4. Thank you for this info! So helpful! Changed alternator on Scion XD 2010. Couple of differences. Cannot remove the adjuster arm - the mounting bolts are too close- just had to hold it out of the way. Wish I had unlocked my doors before disconnecting the battery. Had to remove the bracket the harness attaches to to remove alternator and install on new one.

  5. Wanted to say thanks to the author.

    This article was exactly what I needed to get the job done.
    I found myself in a position without a breaker bar and I'd say it isn't optional. Tapping on the old alternator with a hammer did help loosen up the bottom bolt for me.
    I'd also recommend marking the tensioner position with a marker.
    And it seems in some cases the tensioner bar can't be removed, this makes pulling the old alternator very tricky, it is possible, but I really struggled with it for a bit.

  6. My 'B+" wire cap melted and was red hot ? what could be the issue?