Toyota Yaris Forums - Ultimate Yaris Enthusiast Site


Go Back   Toyota Yaris Forums - Ultimate Yaris Enthusiast Site > Second Generation Toyota Yaris Main Rooms > General Yaris / Vitz Discussion
  The Tire Rack

Thread Tools Display Modes
Old 08-23-2011, 08:00 PM   #1
I've made a post!
Drives: Yaris ´08
Join Date: Sep 2009
Location: Guatemala, C.A.
Posts: 1
Toyota Yaris Battery Light On - Repair

Yaris Enthusiast:

I found this great article about this issue. I did what it says and got the problem fixed. Hope it works for you too.


Jake von Slatt — Mon, 11/02/2009 - 14:22

The day after I returned from SteamCon in Seattle I got into the car to go to the day job and discovered that my battery light was on in my 2007 Toyota Yaris. Being an old Volkswagen man I resisted the urge to get out and hammer on the the alternator with a monkey wrench. Instead I turned everything off and then listened carefully to the engine RPM as I turned on the rear window defroster. When I pressed the defrost button the engines revs did indeed drop about 100 and the engine lugged for a moment until the ECU gave it a bit more gas to smooth out the idle. Good. This exercise told me that the alternator was charging the battery and that the problem was with the warning light itself. I could safely drive the car for the rest of the week and figure things out at my leisure.

This morning I started working the problem . . . by googling "toyota yaris battery light comes on" which lead me to this Technical Service Bulletin EL002-07 Charging System Warning Light "on" . I removed the alternator from the car and disassembled it as per the TSB and discovered corrosion exactly as described. The suggested action was to replace the regulator assembly but, radical makerpunk that I am, I decided to repair it.

Only, it din't need repair. I cleaned it up and scraped away all of the corrosion expecting to find bad connections that I could solder or otherwise fix. Only there was no sign of any problem beyond the surface corrosion on what appeared to be contacts exposed to facilitate testing of the regulator during the manufacturing process.

I quickly came to the conclusion that the battery light was coming on due to conduction between these two test points caused by the build-up of dirt on the surface of the regulator.

So, Toyota's suggested process for re-mediating a problem caused by a design flaw introduced to facilitate their manufacturing process is to sell you a replacement for a part that simply needs to be cleaned? Screw that!

I scraped out the corrosion with a sharp pick, and cleaned up the regulator with a stiff brush and some dish detergent and then filled the holes that were the culprit with some RTV to keep them from collecting the troublesome dirt. I re-assembled the alternator and put it back in the car. It started right up and no battery light! Total repair time was about an hour.

gabo is offline   Reply With Quote
Old 08-24-2011, 07:21 AM   #2
Klink10's Avatar
Drives: 2007 Yaris Liftback
Join Date: Sep 2007
Location: 910
Posts: 1,229
Thanks for the post and links.
Klink10 is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
News : 2007 Toyota Yaris - the little Euro's official arrival VitzBoy General Yaris / Vitz Discussion 9 06-06-2017 12:51 AM
How many forum posters does it take to change a light bulb? silver_echo Off-topic / Other Cars / Everything else Discussions 25 06-27-2011 01:50 AM
NEWS: TOYOTA REVEALS ALL-NEW YARIS SEDAN AT 2006 LOS ANGELES AUTO SHOW VitzBoy General Yaris / Vitz Discussion 5 09-05-2010 08:53 PM
2007 Yaris Pricing Info ! YarisBueller New YARIS Purchase Forum 104 06-24-2009 04:54 PM

All times are GMT -4. The time now is 09:43 AM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2022, vBulletin Solutions Inc.