ABS light coming on after fitting aftermarket radio and reverse camera

[rocker1911]

Hello,

This is a 2007 Toyota Yaris 1.5L automatic with ABS. I have fitted aftermarket radio unit with steering wheel control module and reverse camera. Now ABS and SRS light are coming on right after ignition is turned on. Code P0073 from ABS module Control communication BUS off. Power steering light flashing on every now and then when turning steering wheel and also heavy steering for couple of seconds after engine was started without any pattern. No DTCs on any other modules apart from ABS module. Car drives well without any symptoms. All fuses check ok. ABS module and ECU have been swapped, fault still exists. Only thing I wasn't sure about was tapping reverse camera power and radio reverse input signal into a wire on reverse/taillight circuit board which is measured 12V but not battery voltage.

Any help would be appreciated.