Flashing 4X4 Light

Hello everyone...

I have a 2019 Tacoma Pro. My 4x4 light is now flashing all the time after a snow drive in the mountains. Thankfully the truck is in 2HI and not stuck in 4HI. I cannot enable 4HI or 4LO. I've read/watched many people talking about the front ADD actuator failing due to loose solders or corrosion (water). I've seen people taking these apart and attempting fixes. My understanding is that there is a front actuator and a a rear actuator. While at a stop and slight roll, I hear nothing attempting to engage 4x4 while rotating the switch. Fuse is good.

I've seen Toyota Tech Tip T-TT-0684-22 stating "Water intrusion to the ADD actuator is currently being investigated as a cause of 4WD inoperative complaints. P17A0 and P17A4 DTCs may set for this condition but not always." Recommending: "Please create a TAS case and contact TAS for instruction prior to diagnosing or repairing of the vehicle. If it is a weekend or a holiday, continue with diagnosis and repair. Please save all parts and/or details and contact TAS on the next available workday."

I am not interested in creating a DIY fix for this. I'd rather become versed in the issue and know my options for taking my truck into the stealership. Knowing that Toyota may know of this issue, does anyone know if they have turned it into a recall?

Toyota Tech Tip T-TT-0684-22 can be found here: https://static.nhtsa.gov/odi/tsbs/2022/MC-10209009-9999.pdf

My end solution, if not covered by Toyota, would be to have a trusted service center first replace the front ADD actuator and see if that cures the problem. Any comments or additional recommendations?

 

Does it flash while in 2wd?

Edit: that was a dumb question and i am tired but im still asking it cause im dumb

 

Hi Mater, yes it flashes all the time; 2hi, 4hi, and 4lo. I cannot get 4hi or 4lo to engage nor does it seem to even try when I rotate the selector dial. From reading, it seems the whole 4x4 system is inoperative when the light is flashing due to some fault. I really hope Toyota would make this right if a part has failed.

 

Could be a damaged ABS sensor, or there's a harness on the rear axle that can be damaged. I know @SquirrelBait had something similar happen and the service writer told him it's a known thing when trucks slide into the snowy ditch.

 

I know mine flashes while its trying to get in to 4WD or out of. But for you that sounds like a fault like a bad switch or relay if its always blinking. I would take it in to a dealership and see what it would cost to get fixed. I mean you would have to pay a little for a diagnostic fee im sure. But then at least you would know whats up with it. And try and fix it yourself if possible. But yeah both of us have 2019s and they aren't gonna fix anything for free anymore. We are out of warranty.

 

https://www.tacomaworld.com/threads/4wd-light-blinking.325816/
https://www.tacomaworld.com/threads/how-to-trouble-shoot-4x4-actuator.263525/#post-6447309

looks like these are some threads with some solutions (maybe?) hope you fix it man

 

I'm curious to see if my front ADD actuator has water, corrosion or rust in it. If it does, and turns out to be causing the issue, Toyota should recall the part for a manufacturing (or design) defect. Hell, they called my truck in for the third brake light leaking and said Toyota will fix the light and clean up and mold for free until 2025.

My thoughts now are to have the dealer order a new ADD actuator, open the actuator, make the solders, better seal the box, and then install it and hope if fixes the problem. Who would have thought we'd be playing chase the tail with a "quality product".

 

Just three days ago I was driving on an icy road and my 07 Taco would not engage in either 4X. The 4X icon kept flashing, even when I put the knob back to 2X mode. I pulled over (selector still on 2X) and decided to drive in reverse about 20 feet and the flashing stopped. When I drove off, I attempted to engage 4X again, and this time, it locked in. First time this has happened. I was 4X’ing in the dez a month ago with no issues.

 

Have you guys been following the owner manual recommendations to engage and run 4x4 for 10 miles each month? I think the Taco has that, but it might only be the Tundra. Check your manuals.

 

Thanks 50Buck, I haven't been running it a few miles each month. It worked great all day, disengaged no problem after the mountain trip and the light stayed off for the 40 mile drive home. The next day as I left my house to drive to work, the light stayed on flashing. My main concern is 1) Toyota's ability to diagnose the problem, and 2) getting it fixed. I am really interested in Toyota's Toyota Tech Tip T-TT-0684-22. It seems they may know of the issue and should stand behind their product.

 

Hi Chuy, I will try the reverse fix today! I have nothing to loose on that one!

 

Mine does it every once in awhile, the reverse thing does the trick.

 

You keep mentioning some tech tip note (never heard of them, is that like a TSB?) and that Toyota should stand behind their product. They certainly will (or would) if your truck is still covered by the factory warranty. If not, you will probably either have to fix this yourself or pay them to do it. Doubtful they will do any work for free here outside the warranty, but maybe you can break out your TT note and convince them otherwise.

Good luck and carry on!

 

Hi everyone, I tried the reverse fix, no luck. I removed the skid plate and see that the breather hose has actually fallen off. Perhaps moisture could have gotten in. Does anyone know how to troubleshoot the ADD actuator? I see online that I should have 1.5 to 10 ohms between pins 1 and 2 of the ADD actuator. I am getting 3.3 ohms. My understanding is that this is good and the motor is making contact.

How would I test the 4 wheel drive control ECU or the ADD actuator?