Need Help identifying ABS Codes

[NewfieMZ3]

I have a 2002 M Roadster, which has an intermittant fault which causes the DSC/Abs light to come on. I had a friend scan and pull the codes with the folowing results"

Code 1: A2 - Rotation Rate Signal
Code 2: A1 - Rotation Rate Sensor
Code 3: 76 - Speed Sensor, Signal interference

Does anyone have any comment from this description which wheel it might be. I think I 'll start by checking / cleaning the sensor. Any further advice greatly appreciated...

[Two Rivers]

Test wheel sensor with a volt meter set on AC volts. Have somebody spin the wheel.
You should get a reading of about 0.5 to 3 volts AC turning it as fact as one can by hand.
Check each one.

Next check the resistance of each one.

The test is done at wheel sensor plug.

I always start testing from the wheels first then go up river from there.

I do not know what kind of scanner was used but A2 should be B2 L/F,,A1 should be B1 R/F ..

76=? need to look it up on the scanner used referance guide..

I have also seen where a brake light switch will cause a intermitent light also,, just a heads up, even if the brake lights work there might be to high of reristance leading to the DCS module.

The AC test should work with both analog and digital systems.