4 LO flashing, no 4 LO, engine light and TRAC light on too.

I have a 2012 Tundra 4.6L Crewmax that I use for plowing. I made the usual .7 mile downhill light plow run, mostly idling/coasting, on the way down to the main road to run an errand, switched from 4HI to 2WD once I finshed plowing. I drove about 4 miles and parked for a bit more than one hour and when I started up the truck 3 lights came on. 4LO was flashing, check engine light, and the TRAC light. I messed around with switching from park to neutral and toggling the 2W 4W 4LO dial, turned off the vehicle and started it a few times, because that "fixed" a similar problem last winter.
It sounds like the 4LO flashing can be an issue. Does anyone have any experience with this? I'm not a mechanic by any stretch of the word and am going to call the dealership tomorrow, but I'd like to have some idea of what I can try on my own first.

I'd appreciate any advice.
Thanks.

 

Prior to hitting the dealer, stop at the local auto parts store to see if they have the ability to get the codes that triggered the Check Engine Light.

 

I wish I had a code reader at home! I'd check it out to see if it might be a bad idea to drive it. The truck is in great shape.

 

Very generally speaking, yellow dash lights aren't as worrisome as red dash lights.

 

It’s probably one of speed sensors. Either the cable ripped or water in one of them. My passenger one broke last year. Quick and easy fix.

edit: I can’t remember if both lights were flashing or only one but hope this helps.

 

I had the same thing happen last week to my 2007 5.7L tundra SR5. Codes were P0018 & P0021. Dealer cleaned cam filters, last 300 miles and codes returned. Second dealer (was traveling) said it was a ocv valve sticking open. Had it replaced and went 1200 miles with no problem

 

Maybe a rat chewed some wires, that's what happened to me.

 

I doubt you will hurt anything by driving it if it runs fine. I had similar lights come on but mine also went into limp mode, which for me it ran fine but if i had a trailer behind me, I would be lacking power to pass people. Anyway, I drove it for several days around town fearing what this fix was going to cost me at the dealership. Then one day it wouldn't start, so I threw in another battery and to my surprise, the lights were gone and my limp mode was gone. It's been good ever since. What I am saying is, an easy thing to try first, is disconnect the battery, leave it for half an hour to clear codes, hook it back up and see if the codes come back.

Edit: in retrospect, it could have been that the voltage in the battery was low, causing activation of the codes.

 

It sounds like an ABS issue to me. Could be from either a sensor, one of the harnesses, or a combination. Crawl under there and inspect the sensors for any breaks and feel along the harnesses for any damaged or pinched wires. If you can’t find anything obvious, run over to an auto parts store so they can scan your codes.

Also, just speaking from experience.. if it ends up being a sensor, I’d check out rock auto or similar places first rather than going to the dealership or the parts store. I think AutoZone sells them for like $200+/- each!