4hi flashing

2016 tundra. If I switch to 4x4 it goes into 4x4 but 4hi flashes. If I turn off the truck while in 4hi then back on the 4hi stays lit and doesn't flash. Any ideas what is cause?

 

Probably one of your actuators. I've replaced my diff actuator twice. The flashing indicates trouble shifting into 4WD, but if it stays lit the front diff is engaged.

 

Or a wheel bearing.

Check the wheel speed sensor. And run a scan tool. That will tell you which bearing if that's the issue.

 

I should have mentioned the truck sat for last 2 years unused. It has ultra low miles on it. Would wheel sensor throw a code? Cause it's not showing any codes

 

That has bad actuator written all over it

 

But I know it is physically going in/out of 4x4. I feel the engagement and tested on gravel incline.

Could it be the diff actuator even if 4x4 is physically working?

 

Yes, intermittent issues are common right up until it quits working altogether.

 

Agreed now knowing it sat for that long. Actuators need monthly usage.

 

ok. You guys are right. Front add is not engaging. Its interesting cause i can shift the transfer case into 4hi and 4low. Couple questions...Is there an add relay or fuse? Would I hear if the front add actuator was attempting to engage (similar to how i hear the tcase actuator)?

Thanks for all help.