Tundra Confusion ABS/VSC solid...4HI/LO flashing no codes

Stay with me here, Much trouble shooting done and forcing symptoms as no OBD2 codes present: Most times when I start the truck up, no lights sitting still (Typically after 1 hour or more time shut off). Without the lights on I get significant activation of the ABS module at low speeds, Once the ABS and TCS lights come on NATURALLY the ABS is disabled, so braking returns to "normal." The 4hi/4lo lights begin flashing at speeds above 20-30 MPH (It varies). Strange PART and think CAN be significant (Just don't know why, except transfer case). When the ABS/TCS light are on solid by themselves, I can get them to go out by SIMPLY engaging 4HI. However, once up to speed with 4x4 engaged same dash activity.
So far I have inspected Wheel Speed Sensors wiring and actually replaced the left and right rear sensors and NO change. Last thing: The ABS/TCS and 4hi/4lo ONCE activated stay on regardless until I shut the truck off. If I shut the truck off and start it again IMMEDIATELY, the 4hi/lo are not on but the ABS/TCS are on solid, if it sits shut off, most times No lights on startup until speed. Additionally, IF the 4hi/lo lights are flashing, the truck will NOT engage 4wd. Makes NO attempt to do so. I know this a NOVEL, but any help would be appreciated. Thanks----Bob

 

Have you looked at live data for the wheel speed sensors?

 

If abs is activating at low speed while braking it's almost certainly a failing wheel speed sensor or they are in need of removal and cleaning.

 

@82nd Airborne @WhiteSR5 ....Putting it on a scanner today, already have changed both rear wheel sensors, with Negative result.

 

Look at the live data from the wheel speed sensors: you may have a speed readout or you may have a graphical readout… the output of all 4 sensor should be the same(ish) when driving under normal conditions.

It’s possible that a good sensor is not reading the tone generator correctly, or the connection is compromised.

 

All the stuff flashing or on is a code. Use the color chart here to diagnose. I did it was a drivers side wheel sensor. Usually best to replace the hub as well. I did. No issues. Then the other side failed. new code.