I installed LED headlight bulbs about 1 month ago. Shortly after I had the ABS VSC Traction Control Lights all come on. (Codes CO226 CO236 CO246 CO256 C1223) Hooked up Techstream ran tests, Zero point calibrations and after a few tries it went away and stayed away...well for a couple of weeks. Came back on - same codes. Reset everything again and ZPC and went out to test it. Withing the first 2 minutes lights all back on. Went back and ZPC and cleared and ran Techstream in record mode to look for errors.....nothing, no lights on.
So I went out to run some errands. About 5 minutes into the trip I noticed I did not have my headlights on which I run on all the time. So I flip them on and within 10 seconds all the ABS lights come back on. Has to be a coincidence . So I pull over, turn off the headlights, turn off the 4runner and wait a minute and start back out. No ABS lights. I drive around making several stops for the next hour. On the way back to the shop I turned the headlights back on. Again within 10 seconds, all of the ABS lights back on.

I have now removed the LED headlight bulbs and have gone back to standard bulbs and have had no ABS malfunctions.

I am not sure why the LED headlights would cause a problem. I do have a scan gauge and with headlights on I run about 13.8-14.0 Volts. With the LED bulbs on I run about 13.7-13.9 volts but not sure why. The battery is a fairly new AGM battery that reads 12.3 volts. The LED bulbs do have a fan built into the base of the heatsink. Maybe this is causing some interference?

Anyone else seen this issue?

Update. I went to led headlight bulbs that do not have a built in fan. So far no ABS issues. I suspect the bulb fan motors caused some kind of electronic noise upsetting the ABS system. I've heard of radio noise from these bulbs as well.

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Toyota just released a tech tip I believe for this issue.

Does this still seem to have fixed the issue? I'm experiencing the same thing after installing LED's with fans

Yep. It’s your LED headlights causing noise on the ground of the Skid Control ECU.
The solution is to go back to stock headlights.


https://static.nhtsa.gov/odi/tsbs/20...72379-9999.pdf


Tech Tip T-TT-0597-2
“Some 2014-2020 model year 4Runner vehicles may experience the ABS Light ON with DTC C0226, C0236, C0246 and C0256 stored current in the ABS system.”

Which bulbs you running now? Mine have fans and are quite noisy but no issues.


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Just to add, I have had LED headlights for three years and never had an issue. Then one day my VSC TRAC Brake lights went on and I couldn't for the life of me troubleshoot it. Turns out one of the LED headlights started failing (the light still worked) but the RF noise was messing with the the ABS unit. I replace the LED light with the halogen and the problem went away. I then replaced the Halogen with a new LED light and the issue remained fixed.

So it's not only the brand of LED but it seems if a LED starts to fail for some reason that will set off the warning lights as well.

Thought I'd chime in on this topic...

I too had the ABS, VSC, TRAC, and BRAKE lights all come on. They started coming on just shy of 2 years after I installed LED headlights with fans (Opt 7 is the brand).

I resigned myself to the fact that my brake booster, skid computer, and accumulator were all failing as I was showing codes for all 3, plus 3 speed sensors. I knew this was a common issue, and my car had around 185k miles at the time the lights started coming on, so it wasn't a huge surprise.

What *was* a surprise was that the lights came back on minutes after I replaced the whole unit with a brand new one ($$$$!!). I was SO disheartened. So, I started searching the forums, and found this.

I immediately went and bought $55 Sylvania Silverstar Ultra halogen bulbs and installed them. I've since driven about 100 miles and the lights have not come back on.

Moral of the story: swap your LEDs for halogens before buying expensive parts!

ScottD - Can you update us about your fanless LEDs? I've been looking at them, but I'm not sold. How's the heat output? Any issues with the wiring, connectors, or housings?

Once again, drop-in cheap quality Chinese LED headlight bulbs in your halogen housings are not the recommended way to go. Besides the inferior performance that you can read about in hundred of posts, they may “work” for a while but their lifespan is limited and some are susceptible to causing electronic noise on the system ground. This is not audible noise that you hear, like from the fan motors. It’s high frequency narrow voltage pulses, maybe a volt or two, that are superimposed on the battery ground going to the ECUs, the micro computers in your 4Runner. Computers don’t like crappy power supplies. The Skid Control ECU seems to be quite sensitive to this hence the error codes. Toyota has verified this and have documented it. You have been warned.

I'm intrigued, I had installed Morimoto DRL's and one had burnt out, Morimoto replaced them both on warranty and upgraded me to their newer design. No issues, they look great, but a couple weeks ago my 21 Venture one day threw multiple codes (Pre-Collision System Mal, Drive Start Control Mal, 2wd-4wd mode change Mal, braking power low and ABS Mal).

Curious if the new DRL's are a cause for those codes. Toyota has replaced the left rear wheel sensor and then sent it back. Codes came up again 10 days later. Went back and have now replaced left rear bearing, taken apart the differential and tonight told me they have it being tested overnight for faults in the system. They have disconnected my off-road lights (unclear if it were my fogs and ditch, both from Baja, or if it my DRL's). I thought they were giving up and going to blame my install of the lights, but now seeing this thread I'm intrigued.

Thanks for your warning. To the best of my knowledge, Toyota has only released a bulletin for the 5th gens, not the 4th gens. That's probably why shops don't think to check for fan-cooled LED lights on 4ths.

I sure wish I had seen this thread earlier. I could have saved about $1600. Dealership said it was a bad master cylinder. It wasn’t. I bought Simple twist pop out and and they’re in their halogens is is that what I need to be

On the bright side—I have a new master cylinder. Downside—all I needed was a new headlight bulb. Apparently, this issue also exists in 4th Gens, too.

God am I glad I found this thread. I was experiencing similar issues and they have gone away for now but now I know to be aware of my bulbs causing this. I'm running fan cooled auxbeams right now.

Chinese LED Bulbs are the bane of my existence... even those cheap dome replacement bulbs can wreak havoc with smart key systems.