2015 WW GSR

4WD System Service Required Light came on an evening dallas had heavy rain. I hit a massive puddle on the passenger side Traction Control Light came on and went off as it should.

so here’s the list of troubleshooting I’ve gone through:
1). Tested TPMS Sensors ✅
2). Tested Battery (Replaced)✅
3). Cleaned Wheel Speed Sensors✅
4). Tested AYC Relay✅
5). Tested ACD/AYC Pump Load,Voltage, Pressure, & Fluid. (Yes I cracked the 2 bleeders on the backside)

Light turns off each time I shut down the car. Sometimes it takes some time before the light kicks on, but usually once I’ve either had to turn the wheel or get above 30mph.

Then more often it just pops on when I’m pulling outta parking spot. This leads me to believe it’s SAS, but I can’t get the dang car to throw code. Nothing at all

 

I guess its not the AYC pump going out..

 

Sounds like it could possibly be a failing abs/wheel speed sensor. They will throw intermitent 4wd service/abs/asc lights. Normally the malfunctions will display on the info screen, accompanied by beeping. Itll give you the option to "clear" the messages after a few seconds by holding the info button, although a exclamation point will remain on the screen, along with the yellow lights. If the 4wd fault is set, it will also disable the tarmac/gravel/snow modes. Turning the ignition off fully and turning it back on will often reset them, once you begin to roll, but other times, itll come right back. In my experience, there wont be any hard codes stored within the obd2 diag system. I believe you need a etacs scanner to see the codes. I had a condition where the car would trigger a 4wd serivce required light, a abs service light and occasionally, a asc light. They malfunctions would sometimes occur after a 45min or longer drive, during speeds under 20mph, or after turning with the wheel close to full lock. Every now and then, i would get a blinking traction light, right after making a turn where the wheel was close to full lock. Sometimes the lights would clear if i shut the ignition off, then restarted it. Other times, it would come right back on. The lights would always clear if i allowed the engine to cool down completely. I was able to fix the issue by replacing a faulty wheel sensor. Apparently, high heat from braking, wear from brake dust, shock from being hot and getting drenched with water, can all cause a wheel sensor to fail. They also seem to fail intermittently, which causes all the symptoms ive described. You just need to figure out which sensor has the issue and replace it. They just thread into the knuckles and read the cogs on the axle ends, probably by some type of hall effect sensor. Its just a sensor with a pigtail harness and a plug connector. I also tried to clean mine prior to replacing the one faulty sensor, but i had no luck. The good thing is, a faulty wheel speed sensor wont effect driveability, aside from the sawc and asc being disabled. I believe the car still imparts some degree of traction control, and obviously, the awd will still work, even with the malfunctions active.

 

It very possibly could be. I once had a flat tire, and the "4WD System Service Required" light came on. The light no longer turns on after the tire is replaced and inflated.

 

I just went through the exact same thing.
I replaced the two front speed so sensors and that didnt clean it up. Cleaned the rear two and test then. Nope. Noticed the right rear hub bearing was going bad. Replaced it and it clear the code up. Lots of crud and rust inside the hub. Guessing it made the sensor miss read.