abs computer not responding

The ABS computer is completely different from the PCM. You need a scan tool that will communicate with the ABS computer. Also, each time you shut off the ignition the ABS computer is cleared. It does not store trouble codes. So in order for the codes to be read the ABS light has to be on when you scan it. If the ABS light comes on and stays on when you start the engine it's a sensor or the related wiring. If the ABS light comes on when you start the engine, goes out, but comes on again when the vehicle starts moving it's the pump and modulator assembly. The ABS computer checks everything except the pump and modulator assembly when you start the engine. The pump and modulator assembly is not checked until the vehicle begins to move after the engine is started. Hope that helps! Jim