Toyota Says it Might be the Bulbs
Some 2014-2020 Toyota 4Runner vehicles may experience the ABS light on, with DTC C0226, C0236, C0246 and C0256 stored in the ABS system.
Inspect the ABS connector for signs of damage. If OK, go to Step 2.
Use a Picoscope to monitor the ground to the Skid Control ECU with the engine running and headlights on, then with the headlights off. If the ground circuit voltage fluctuates with the headlights on as compared to headlights off, go to Step 3.
Inspect the headlight bulbs for any aftermarket parts such as LED or HID bulbs. If aftermarket bulbs are found, perform the same tests with factory headlight bulbs.
Example of skid control ground with headlights on. Note the difference with headlights off.
Example of skid control ground with headlights off.