codes c0226-c0221 and c0227 are coming up on 1999 gmc k15004x4

Question

the abs light comes and goes does not stay on all the time ware is a good place to start looking

Answer 1

C0226 Wheel speed sensor Left front

C0221 Wheel speed sensor Right front

C0227 Wheel speed sensor Left front

The first place to start is to make sure that the hub and bearing is in good shape, where the bearing has no excessive play, you would do this by lifting the tire off the ground and checking for any excessive play on the wheel bearing , and check the tire pressure

 The wheel speed sesnor is part of the wheel bearing , excessive play in the bearing will set a wheel speed sensor code, as well as tire pressure and tire size