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.

 

Shoot straight can you post that chart another way? I can't zoom enough to make it out clear...I appreciate you in advance.

 

The chart @shoot-staight posted is a fantastic reference. You can find it on the site by searching posts by trident.

If you are using a simple OBD2 reader, it doesn’t read body modules. You need a more advanced reader to check sensors and modules; they can communicate with each sensor via CAN to cycle and diagnose them individually. I have a friend with a shop that let me use his to diagnose a bad wheel speed sensor. The chart above told me it was a whee speed sensor, the advanced reader told me exactly which wheel it was.

 

Here is a little better one.

 

Gotchya blenton! Fairly sure it went in to protective mode, and needs a reset. For the story:
Trucks been sitting 4 years. I finally got the motor in and running and it was stuck in 4lo. Messed with t case actuators and screwed timing up, tried to shift out a horrible noise then nada ever since. Got back into actuators and set timing and rods in correct position (this forum helped greatly). Voila! The truck was in 2wd and I finally drove it, even made it few miles home from my buddies house. Now 4hi, 4lo, vsc off, flashing and traction control solid.
Thats where I'm at...just gotta find someone with fancy snap on reader.

 

All...Still was not able to get to the scanner to diagnose. Appreciate post! Thanks for the chart but it doesn't seem to have any scenarios that fit MY Indicator Lights. VSC/ABS solid, 4HI/LO flashing. There is no Brake, Check, or Trac off lights. However, when I pull the ABS1 (50 amp) fuse, THEN i add an ABS light solid. Appreciate for all the replies!!