"Flashing 4x4 light" issue

We can start diagnosing it with an ohmmeter, pulling off the tranny skid, by accessing connectors on both transfer case and front add. Up for that kind of work?

As Tony said (unless we are just throwing parts at it), cant give much other help without getting into the measurements on the actuators, or the data given in techstream.

If up for it, I will help

 

Yep. Had to this several times today. Now it's fine.

 

So rad. If this was me I'd be all over it lol

 

Thanks for the knowledgeable responses - the techs at the shop did the ohmmeter check across the ADD and found a moderate voltage drop. After disconnecting the ADD, the voltage ceased dropping. They've ordered new parts for it, we'll see what happens Monday.

I was unaware of the ADD system until this issue cropped up, so this has been enlightening.

Assuming this is an ADD issue, are there any steps I as an owner/overlander can take to safeguard the system from damage, or to prevent it from leaving me without 4WD in the field?

 

Not alot to do. Exercise it regularly. Engage 4wd before you get deep into stuff and leave it engaged. Be careful in soft sand (depending on your skid plates.) Have had a report of an ADD broken when soft sand got compacted into the ADD on top of the skid plate.

The 4wd system on this truck is definitely 'delicate', in that it will failsafe to lock out mode changes for a lot of detected failure modes.

We have discussed on the forum briefly building a breakout box to allow manual electrical control of the two actuators in the 4wd system. Assuming the actuators are still semi-functional, this would allow you to climb under truck, hook up box to existing connectors, and engage 4wd.

 

Problem has been resolved! Thanks everyone for your input, especially BigWhiteTRD. The ADD was indeed the problem, but I couldn't get any more specific information out of the tech; I don't think his knowledge extended much past "Toyota told me to replace it, so I did, and now it works". Hopefully it's just a fluke. Glad I've still got some warranty miles left on it. Not gonna complain about getting a new transfer case out of the deal too

It's interesting you mention soft sand though - the issue first began manifesting the day after I explored the Carcross "Desert" up in the Yukon territory. Perhaps it's a coincidence, but perhaps not. At any rate, I'll take it easy if I ever find myself in sand again.

Has anybody experimented with beefing up the breathers down there? I don't know that it contributed to my failure, but I've heard them mentioned as a source of consternation.