TC reported Obstacle Detector alarm at car 1649 near B3 train doors. Fault subsequently self-cleared . ~~~~~ 1649 TC reported Obstacle Detector alarm near B3 train doors. Fault subsequently self-cleared. CE checked/found 1649 check for obstacle detection alarm found ok. Check B3 door ops found ok. OE Tan request 1649 B3 door operational check & download FC.  1649 ER D/L & found no abnormalities. No FC recorded on TIMS. Checked for FOD - Not found. Checked door guide & J-rail - OK. Cleaned J-rail as preventive measure. Checked door resistance = 6.5kg. Manually pushed both door leaves & no abnormalities found during door movement.  Au TK 44736