3556 BCU fault. ~~~~~ 3556 BCU fault.  555/556 ER D/L - Done. Replaced 3556 BCU & 1555 ACU - Done. Function test - OK. Brake pressure test - OK (refer to attached checklist). Air leak test (0.3 bar/5 min) - OK. 3556 BCU S/N : OLD : 200-7262 NEW : 18100-73 1555 ACU S/N : OLD : 1042-071 NEW : 1024-030  Chan GF/Selvan 44050