2015: 4HI Engaged Without Driver Touching Control

Hi,
I have a 2015 Tundra that upon engine start automatically engaged the 4 wheel drive high setting, with the 4HI light indicating as such and while driving it was evident that all 4 wheels were locked. The shifting knob was in 2HI and remained there.

So I made an appointment at the dealer but when I started it up the indicator light was no longer illumined and consequently, they were not able to identify any issue.

If anyone has any insight, would be great to hear.
Truck Details:
2015
Type: 1794 (Crewmax)
Miles: 53,000
Infrequent use of 4HI, most driving on pavement, sadly.

Thanks all.

 

Can you share a bit more?

1. How often does/this this occur?
   
2. Does switching to 4WD and then back to 2WD correct the issue?
3. Have you done any work to your truck recently?

 

Is 4HI solid or blinking? Is that the only light on? No traction control or abs also? I had an issue when 4LO(blinking)+ 4HI(blinking)+ ABS(solid)+ Traction(solid) were on and it turned out to be driver wheel speed sensor.

 

It's a use it or lose it scenario...once a month one should put it engage 4wh and 4wl...have you done any transfer case fill and refill maintenance lately?

 

@mountainpete thank you:

1. How often does/this this occur? A: It's only ever happened once.
2. Does switching to 4WD and then back to 2WD correct the issue? A: Tried that and no change.
3. Have you done any work to your truck recently? A: No work, but just before this occurred, I hauled 1 ton of rock in bed, which I've never done.

@JeffMac the light is solid and that is the only light on.

Thanks @HulkSmurf14 no transfer case maintenance lately. Have meant to periodically engage 4HI and 4LO, just failure to execute on my part.

 

FWIW, I've gone my whole life just engaging 4WD on trucks when I actually need it and I've never had a problem. Now I may need it more than some in the winter, but the rest of the year it doesn't see that much use, and my experience mirrors everyone I know with a 4WD vehicle. I realize it's in the manual, but I think the 10 miles per month thing is overkill, especially given many end up doing it on dry pavement.

What's described in the OP doesn't strike me as anything that would be a result of too infrequently exercising the 4WD components.

 

Maybe rodent damages on wiring.

 

Best idea yet.

 

Agreed. It sounds electrical to me.

 

If it has only ever happened once I wouldn't spend much time chasing it.