Step 3: Check the Central Locking Fuse. Remove the metal key from the keyfob and use it to unlock the doors manually. Next, you need to check the fuse for the central locking circuit. Not only that, but also look at the fuse for the Antenna Module and AAM.. Because your MB receives the lock / unlock signal via the antennas installed on your car, a bad antenna module fuse can also cause the Insert key into ignition and turn to ignition and back 4 times in quick succession. You will then hear a chime which indicates you are in the central locking programming mode. remove key and press the lock and unlock (although I only needed to press the lock) button on the remote. Unfortunately, there are many electronics and moving parts involved, so it's possible to find your car's central locking system not working at some point in time. A failing car central locking system might be due to a blown fuse, faulty solenoid, or electrical wiring issues. 01553 - Motor for Central Locking; Passenger Door (V57); Lock 012 - Electrical Fault in Circuit - Intermittent Freeze Frame: Fault Status: 00101100 Fault Priority: 3 Fault Frequency: 5 Reset counter: 126 Mileage: 69101 km Time Indication: 0 Date: 2023.14.30 Time: 18:43:49 00929 - Locking Module for Central Locking; Front Passenger Side (F221) Click to expand I also have a 2003 SL500 with problems in: 1) Central Locking System - Door and Trunk Locks work with Physical Key, but neither Keyless Go nor the Traditional Remote Key. 2) Retractable Roof, doesn't open nor close. Red Light just flashes, referring to instructions, but the Trunk cover is in place. bnKY.