My 2004 RX 330 with 213,00o miles, Has started to activate the Swerving light on dash. at low speed 30 mph. Then it activates the brakes (Holding steady on the gas) car pulses the brakes and slows! Had mechanic connect scanner. NO CODES!) Took for drive with scanner connected. No codes but braking and flashing light occurred steadily. Any ideas?

maybe clean the ABS sensors?

What Tom said. Here's a thread with the same problem and includes photos of dirty rear ABS sensors.

https://www.clublexus.com/forums/rx-...op-solved.html

If the ABS tone ring on any of the wheels is broken it can activate the ABS at low speed,,,if you can take every wheel out and check the opening above the tone ring behind the wheel hub while rotating the hub you will be able to see the ring moving,,if one of them is broken needs to be replaced,,,for mine I bought the individual ring,,they took the drive shaft out ,at a press shop they replaced the ring and put every thing back,,,no more ABS activation
good luck
The opening to look is the one after taking the ABS sensor out,,so clean , look and check there