TC reported TIMS showed FM1 A2 door didnot open. Fault only showed at DBG NB. Staff (NEW) boarded a nd confirmed train door at Front M1 A2 door did not opened. TC also feedback fault recurred at NEW NB. Staff (NEW) assis ~~~~~ 1601 ER D/L & found FC 30 & FC 36 showing door lose communication (Comm. fault) during function test when fault was simulated. Suspect DCP failure as fault only happened to 1601 A2 door.  Jefferson. 27/02/2020.  1601 A2 door DCP swopped to 1601 A3 door. Replaced 1601 A2 door operating mechanism. Cyclic test 50 times - OK. 1601 A2 Door Operating Mechanism S/N : OLD : 1405W0200315001 NEW : 1412W0200415906  Goh AT/Chan GF/Alcus/Anand. 27/02/2020.