Fix ABS light on Honda Civic
If you own a Honda Civic with an ABS light on with code 81-01 ABS module failure (Central Processing Unit [CPU] Internal Circuit Malfunction, don’t automatically assume you got a bad ABS unit. Start your diagnostics by checking the powers and grounds to the ABS unit. Check for battery voltage on terminals 8-9-16 and ground on 24 & 25. Also make note of the actual battery voltage while the vehicle is running. If the alternator is overcharging, it can cause this ABS code to set.
So if you’ve checked the powers and grounds and they’re good. Clear the code and disconnect the alternator. Then start the engine and see if the code sets again. If it does, then you’ve ruled out an overcharge-induced failure and the ABS modulator control unit must be replaced
© 2012 Rick Muscoplat