ABS,T/C,brake light on. 06 Lacrosse. Code RR circuit open. Cleaned the ABS unit. All the lights came back on. Attached scanner while driving it showed the wheel speed for all wheels was accurate.

SOURCE: What is a Code 84

Hello
Welcome to FY
I would check your speed sensor located on the rear end this is on top of the housing this will throw that code too.
RD

SOURCE: Pontiac G6 ABS Problem

when the ABS light comes on you will not hear or feel anything cause soon as the ABS light comes on the ABS is disabled
sounds like it is weather related (rain,snow)
i would check both rear wheel speed sensor harnesses for water intrusion if you see any corrosion (green) on the terminals replace both the hub and harness
if there is no corrosion then check resistance of the sensor also check for a short to ground
if that is ok then put some dielectric lube on the wheel speed sensor terminals and clear the codes and see what happens
intermittent problems can be hard to find
hope this helps

SOURCE: Rr.ABS and the brake lights on

CHECK TO MAKE SURE WITH CAR RUNNING VOLTAGE AT THE BATTERY SHOULD BE 13.5 VOLTS TO 14.5 VOLTS. USE A DIGITAL VOLT METER TO CHECK VOLTS AT BATTERY. WITH ENGINE OFF BATTERY VOLTAGE SHOULD BE 12.5 VOLTS. IF NOT ALTERNATOR NOT CHARGING BATTERY.THAT WILL MAKE ABS AND BRAKE LIGHTS COME ON AND A FAULTY BRAKE LIGHT SWITCH WILL ALSO CAUSE ABS AND BRAKE LIGHTS COME ON.IF ALL LOOKS GOOD.HAVE THE ABS BRAKES SCANNED.IN THIS CASE YOU ARE HAVING BRAKE FAILURE.BECAUSE WHEN BRAKE LIGHT COMES ON THATS WARNING BRAKE FAILURE BECAUSE THE BRAKE MASTER CYLINDER AND ABS UNIT IS TOGETHER AS ONE.NOT SAFE TO DRIVE.COULD LOSE BRAKE CONTROL AT ANY TIME TOW IT IN.

SOURCE: i scanned my 06 chrysler 300 abs.it said left

try taking battery off for half an hour and retry

SOURCE: abs code c 0036,front left wheel speed circuit range / performanc

I agree that it is more then like the the hub bearing assembly that also houses the speed sensor I would first check that there is no damage to the wiring that goes to the hub bearing that could be easy repaired, or debri that has been caked in between the sensor & the hub, use an air preesure to clean it out. Hub bearings are very expensive, so try this first. Good luck