Update - sorry the next day the light is back on. Drivers rear wheel has excessive brake friction on the caliper and may be causing the problem - I may investigate someday........

Just wanted to post this fix hoping it will help anyone else.

'93 LS400

~240,000km

had the brake fluid flushed

soon after the flush was performed the trac light - the one that flashes when it's helping you gain traction (not the TRAC OFF) light, started coming on after a minute or so into a drive. The traction control would function until this light came on, then it wouldn't function. Sorry - I can't remember the code # (might have been 43) but I remember it was referring to a break in the trac system "link" or so I understood it

This went on for about 20,000 km

Anyway my friend suggested there was likely air in the lines. So we did a bleed both at the actuator and each wheel. A bit of air came out.

Went for a drive used brakes frequently, light came on. Stopped & restarted engine. Light has been off since.