Turning to the Forum for Help!!

I have a ‘17 TRD OffRoad with 100k miles, 2.5” Dobinsons Lift. Lift was installed in 2019, no issues for 2 years until about two months ago while on an 8hr drive home from West Texas when the ABS, VSC and Traction Control lights came on. I noticed bc cruise control immediately went out. Ever since, these lights are very intermittent, some days they come and go, sometimes they stay on for hours at a time, sometimes they don’t come on for a week or longer. When they are on, all of those systems are non functioning, also no cruise control. 4WD works, however, occasionally the rear diff lock light will blink as well. When the rear diff lock light is flashing, I have no 4WD. Typically this only happens when I have been driving for hours on a long trip, the ABS, VSC, and Traction Control lights have to be on for awhile then the rear diff lock light will come on and blink.

When the lights are not on, all systems work great.
I have changed out all ABS Sensor wires and all ABS Sensors. I have performed the Zero Point/Yaw Rate Calibration numerous times. I have donek it with the lights on, and with the lights off. It does not help.
No check engine lights or codes. If the lights are on, the only way to clear them is to turn the vehicle off and let it sit off for more than 4hrs (overnight). When I come back, the lights will be off and will only come back on randomly as I’m driving. Could be a few days, could be instantly.

I’m stumped. I’ve read every article I can find with this combo of lights and everyone says ABS sensor wires or the sensors themselves. I ohmed all the original wires and sensors out and they all appeared to be fine, but I changed them anyways.

Trying to save a trip to the dealer, having a friend with Techstream come by next weekend to plug-in and see if that tells us anything. Turning to the forum for help, suggestions and/or advice. Thanks in advance!

UPDATE: 7/27 @8am CST - I managed to scan the ABS sys this morning, all wheel speed sensors are functioning properly. I drove for about 20mins on the highway and the same 3 lights came on, scanned ABS again, all wheel speed sensors are working. Now I’m thinking I need to start looking for sensors related to the VSC and Traction Control system…any thoughts on what I should be looking for??



SOLVED: The dash lights were being caused by the rear diff e-locker indicator switch mounted atop the rear diff with the 2-wire plug attached. After reading about this particular indicator switch, it is apparent that this is notorious for failing on all Generations of 4Runners. It’s a simple brake light indicator switch that used to be mounted under the brake pedal in older cars. When the brake pedal is pushed the switch activated, turning brake lights on. In our case the switch is mounted atop the rear diff with the switching mech inside. When the e-locker button is depressed, the e-locker motor activates, locking the rear diff, which in turn pushes the indicator switch, activating it. When the ECU reads a signal from this indicator switch it deactivates ABS, VSC, and Trac Control. Hence the reason I was seeing these lights, the switch had failed and was always sending a signal to the ECU. Swap the switch out, lights go out, everything goes back to normal. Toyota gets close to $80 for one of these, or you can order from RockAuto or eBay for less than $15. Just cross reference the Toyota Part #. I ordered a spare to keep in the glove box as it seems very easy for this switch to go bad, seeing as how it is immersed in the diff fluid and exposed to the same heat and pressures that the diff carrier components are exposed to.

Also discovered that my e-locker motor was locked up. It is not activating. The working theory is that due to the low whine I heard (read below for more info), when the failing indicator switch was sending a signal the ECU kept trying to unlock the diff, which was already unlocked. So, the e-locker actuator motor was just turning full force against itself. It was unable to find time to take it off this past weekend, but I will remove it this weekend, take it apart, ultrasonically clean it, remove all rust and build up, lube it up and reassemble to see if that will fix it. As long as none of the windings are broken, it should be repairable, and as noted below by lbro23, these are supposedly really simple and easy to rebuild. Will post back an update on the e-locker actuator motor when I complete that. As for the moment, this issue has been solved and I have no lights on my dash. Thanks again lbro23!