TC reported air-con fault at car 1541. Unable to reset. Staff(RFP) checked and confirmed no air-con faulty. Car was cooling. ERS-14 ~~~~~ TC reported air-con fault at car 1541. U     Tims shown #1542 a/c 1-1 coolant fault.Further check found low freon and check CCU found LP charging point having freon stain,suspect charging cap NG,replace charging cap and top up freon.Monitor cut in/out and cooling ok.#1541 a/c 1-1 check freon and cooling ok,no fault observed. Done by Rizman/Kalee.  29/07/22