Train EB was applied in Auto mode due toObstructed motion. Released EB-ok. Train unable to proceed in Auto mode. Fault recurred at YIS1. Proceeded in ATPM to t he next station. TSC did a VOBC switchover to no avail. TC d ~~~~~ 3551 AMR1 & AMR2 replaced due to high resistance. #3552 checked - OK. To arrange for M/L testing.  Au TK. 28/12/2020.  551/552 M/L test. #3552 : ATPM & Auto Mode - OK. #3551 : ATPM - OK. Auto Mode - Failed.  Au TK. 28/12/2020.  3551 ASAR, SNR, SR-2 & CH3R checked - OK. Checked continuity of 7028 to 7034, wire 7010 to 10287H - OK. Found SNR2 intermittent jammed. SNR2 waiting for spare. Replaced ASAR as preventive measure.  Goh AT/Chan GF. 29/12/2020.  3551 SR contact checked - OK. Energised voltage 107.2v. 7005 to 7006 resistance 0.10 ohm. DTO (AM) AMR contactor able to energise. MDR & BDR checked - OK. Checked wire 7046 to CBTC K20, K47 to 7044 - OK. Voltage from CBTC Auto Mode - oK. Replaced SNR2 & Ohm reading test - OK (0.1 ohm). Refer to SIG L N/O 2234142. Joint inspection with OE. Found CBTC DTOR-3 having fluctuating high resistance. Refer to SIG L to follow-up. To follow-up with M/L test once SIG L replaced faulty relay.  Goh AT/Chan GF. 30/12/2020.  551/552 M/L test from UPD-JKN-UPD. #3551 able to proceed in Auto Mode.  Au TK. 01/01/2021.