Lexus GS ABS Traction Problem

Sounds like a speed signal fault. The ABS, traction control, and even the transmission rely on that signal. Since it's a hybrid, could the inverter be playing a part? And have you checked the wheel speed sensors themselves for damage or corrosion? They are usually the first suspects.

Hmm, the inverter... that's a thought I hadn't considered. How would a problem there manifest itself in this kind of issue? And if the wheel speed sensors were at fault, wouldn't a diagnostic tool pinpoint that?

The inverter could, theoretically, introduce electrical noise that interferes with the speed signal being sent to the ABS module. While a diagnostic tool should pinpoint a wheel speed sensor, sometimes the fault is intermittent, or the signal is just weak enough to cause problems without throwing a specific code. Considering all the symptoms together, I'd say it's most likely a defective control unit. I'd suggest having a workshop take a look.

Thanks for the advice! I took it to a trusted workshop, and you were spot on - it was a defective control unit. They replaced it, and it cost me around 1000€. Everything's working perfectly again. Really appreciate the help!