4wd light stuck flashing green (2018 trd offroad) **fixed**

**update** it was the add, I finally got around to putting the new one in which had water in it and replaced front and rear diff fluid while I was at it and just replacing the add fixed it. Thanks for all the advice here I appreciate it . No other issues since going through all that water, I should explain the water wasn't up to the hood probably halfway up the front grill and driving through it made it go up to the hood (still not good I know)
Also put on some clamps to the breather tube which suggest anyone who goes through any amount of water do it's super easy.

Some backstory, last month I was pulling people out of the storm water in California because they kept driving through 3+ feet of water in their cars. I drove through the water maybe 4 times and the last time the water was going over my hood. I never engaged 4wd but the next week my rear differential lock light would start flashing green and now it is stuck on regardless of whether I press the button or not. also switching to 4h or 4l does nothing now, no flashing lights and wont engage at all.

the light comes on as soon as I start the truck and will not turn off no matter what.

Now here's what I've tried so far,

*checked the fuses all good
*checked the connections on the diff all dry and looks good
*loosened the diff sensor and wiggled it maybe 1/4 inch
*checked the vent hoses and both were off and dangling so I put them back on
*tried engaging 4wd and did every little trick (turning left, right, figure 8, backwards, forwards you guess it I tried it
*no damaged wires that I could see
*disconnected the battery for 10 mins
*gently tapping while trying to engage 4wd


4wd worked fine the month before this started happening any advice would be awesome.

 

no, it is flashing green which mean ready to engage but its not engaged.

 

Have you checked your diff fluids to make sure water didn't get in from being submerged? You mentioned the "vent hoses were off and dangling", is that referring diff breather hoses?
Have you tried disconnecting the battery for 30+ mins? It's my understanding some vehicles (unsure if specifically the tacoma) wont do a true reset with any shorter timespan.

 

Diff lock light is red on my '16 and all Toyotas I remember. Yours is really green? 4wd light is green. You have a picture of said light?

 

Yeah, that's the 4wd light if it's green, diff lock is red. Kind of moot at this point, but don't drive in water of unknown depth, for any reason (especially to "help" others who already made that gamble, and lost) unless you're fine with totaling your truck. By far the quickest way to total a vehicle, and just because it's a truck doesn't mean there aren't sensors mounted low enough to get submerged. Electrical gremlins on water damaged vehicles are an absolute nightmare to deal with. Best of luck.

 

change the diff fluid. you should do so every time you submerge it in water. i would get some electronic cleaner spray and clean all the connections too.

$9 CRC 05103 QD Electronic Cleaner -11 Wt Oz

CRC 05103 QD Electronic Cleaner is what i use. It's great stuff. i wouldn't ever do that again. trucks aren't really designed to hold up long-term when you submerge them in water.

 

Sorry for your situation OP, but the lesson learned here is nice guys finish last! I have a cabin in the north Georgia mountains and cabin renters routinely getting stuck in a parking area at the cabin located at the bottom of the hill from my place.

When asked if i can pull them up the hill with my OR, I decline citing safety and liability concerns (which are very real). I give them the number of a local towing company and wish them a pleasant stay.

 

The depth of the water was not unknown, not sure what you are even talking about and they weren't strangers the were my neighbors who were stranded.

I'll never understand people who comment on a forum just to insult someone and offer nothing of value.

 

Your right it is the 4wd light

 

Sounds like a plan, I figured water and dirt got in from that breather tube and messed something up but I was hoping it was something more simple.

 

I never said strangers, nor did I insult you. By far the most common type of catastrophic failures I've seen on these trucks involves deep water, so I thought I'd throw in my $0.02 about why it's not a good idea to drive in deep water, which seems to have caused your issue. Anything going over the hood is far too deep, but hey man, it's your truck. Apparently it also wasn't helpful to confirm your issue is with your 4wd, not your diff lock. My bad. Hope you get it fixed, it should be easier than fixing your knee-jerk defensiveness.

 

Lol I browse this forum daily and it always filled with people like you giving advice on how to use your truck and not actually helping with the actual situation and it just junks up the forums. I got to call it out sometimes or else when someone else has the same problem they will have to sift through pages of unhelpful comments.
Like no shit you shouldn't drive your vehicle through water but I wasn't asking driving advice on what I should and shouldn't do during a hurricane. If I want to help out all my neighbors and pull their cars out of the water that's my choice and I live with the consequences. There's no need to comment about my poor decision making choices just give actual advice or don't and move on.

 

Do you know why "people like me" comment about people's mishaps? Because I don't understand people like you that come here and post about something stupid they did and then act completely shocked when they receive the absolute smallest amount of what could even be perceived as criticism (that wasn't even intended to be), that was also posted after useful advice to point you in the right direction. A blinking diff lock light is a different issue than a blinking 4wd light, so you were asking the wrong question. Let me know when you find a forum that is 100% useful advice at all times with no criticism, I have a bridge to sell you.

By the way, search for your problem before you start claiming that I'm "junking up the forums" when your problem has happened dozens of times, it doesn't need a new post (that actually makes it way harder to find answers than extra comments). My money is on your ADD actuator. Here, in case you're still too high up on your horse to search for yourself:

https://www.tacomaworld.com/threads/4wd-lights-flashing.738637/
https://www.tacomaworld.com/threads/water-killed-my-4-wheel-drive.307663/
https://www.tacomaworld.com/threads/4wd-flashing-help.89013/
https://www.tacomaworld.com/threads/flashing-4x4-light.794026/

Learn some humility, it's good for you.

 

Fix that title op

 

East Coast Gear Supply recommends using conventional gear lube, especially if you submerge your diff often. it tends to lube better in the presence of water, compared to synthetic. but always good to change it out ASAP if you want your differentials to last the life of the truck. mud and gears don't mix well.

i checked the service manual and it says to check/replace the 4WD Control ECU Assembly if your rear diff lock light is stuck on. i'd start with cleaning those connections, or any others that were submerged. but i'm thinking you will have to replace that 4wd ecu. looks like they are around $305 from online dealer parts store.

do you have any codes?

 

Per above post, it's actually his 4wd light, not Diff Lock. So it's his transfer case, not rear diff that seems to be the issue. Or the things controlling it.

 

changing the diff fluid and having it be fixed is about the simplest of the possible fixes and should be done anyway. If you haven’t done it before it was probably due from miles regardless of driving through the water. It’s really easy to change, plenty of info on YouTube or this forum. Hope it solves the problem!

 

Please change the title of your thread so folks see it's actually the 4WD light that is flashing, not the DIFF Lock. Your issues seems to have nothing to do with your rear differential, but instead a sensor or actuator on your Transfer Case (the transmission like thing that engages your front driveshaft for 4wd).

 

ah, well that changes things. i'd say it's an issue with the actuator. they are the weak link, generally. i'd just take it off and clean it really well.