TC reportedcar 1656 'A4' train doors did not opened. Staff (PSR) confirmed fault.Train doors sel f opened before SM(PSR) was able to isolate. SM(RFP) confirm ed fault. Unable to isolate in closed position. ~~~~~ 1656 TC reported  A4 train doors did not opened. L3 Staff (PSR) confirmed fault. Train doors self opened before SM(PSR) was able to isolate. SM(RFP) confirmed fault. Unable to isolate in closed position. L3 1656 No FC registered. Checked door leaf & found 1656 A4 door LHS and RHS outer door rollers delaminated - Replaced all faulty rollers. Checked DLS & DCS - OK. No FOD found. Cleaned J-rail & door guide as preventive.  Jonathan Koh 45257