Train doors at front M1 car were not proven closed. Suspected isolated'A3' were not proven closed.Staff (COM) assisted to clear fault but no avail.Pax weredetrained and trainwithdraw to UPD via OTPSD. ERS-10 ~~~~~ 1533 Found NO clearance between latch & stopper - Adjusted. Open all lintel cover to check all clearance of all doors when SDIC isolated - All OK. Tested Door operation when 1533 A3 isolated - OK (No DIR). Cyclic test door operation 20x - OK. Resistance test - 7kgF. Jervis. 11/04/21.