LG TCD fault codes indicate abnormal operating conditions detected by the elevator controller. Most faults fall into several categories, including drive system protection, encoder feedback, communication, positioning, door operation, and safety circuits. Identifying the fault category can significantly reduce troubleshooting time.
Common LG Elevator TCD Fault Categories
1. Drive & Inverter Protection
These faults are related to the inverter, motor drive system, and power electronics.
|
Fault Code |
Description |
| TCD-21 | IGBT Short Circuit |
| TCD-22 | DC Bus Overvoltage |
| TCD-23 | Overcurrent |
| TCD-34 | Low DC Voltage |
| TCD-75 | IGBT Heat Sink Overtemperature |
These faults are commonly caused by power supply abnormalities, inverter module failure, excessive motor load, or poor cooling.
2. Position & Encoder Faults
Accurate positioning depends on encoder feedback and floor reference signals.
|
Fault Code |
Description |
| TCD-40 | Encoder Failure |
| TCD-46 | Encoder Wiring Fault |
| TCD-60 | Floor Distance Measurement Error |
| TCD-61 | Position Synchronization Error (After Power Recovery) |
| TCD-62 | Position Synchronization Error (During Normal Operation) |
| TCD-73 | Floor Level Sensor (FML) Fault |
When these faults occur, technicians should inspect the encoder, leveling sensors, forced slowdown switches, and perform hoistway self-learning if necessary.
3. Speed Monitoring Faults
These faults indicate abnormal elevator speed or acceleration.
|
Fault Code |
Description |
| TCD-41 | Inspection Speed Overspeed |
| TCD-43 | Speed Monitoring System Fault |
| TCD-50 | High-Speed Overspeed |
| TCD-51 | Speed Variation Fault |
| TCD-64 | SDS Speed Fault |
| TCD-76 | Excessive Deceleration Time |
Possible inspection points include the encoder, inverter parameters, motor performance, and brake operation.
4. Communication Faults
Reliable communication between controller boards is essential for elevator operation.
|
Fault Code |
Description |
| TCD-17 | Car Controller Communication Fault |
| TCD-80 | Group Communication Fault |
| TCD-81 | COMM Board Communication Fault |
These faults may result from damaged communication cables, unstable power supply, or faulty control boards.
5. Door Operation Faults
Door system failures are among the most frequently reported elevator faults.
|
Fault Code |
Description |
| TCD-86 | Door Opening Fault |
| TCD-87 | Door Closing Fault |
Technicians should inspect the door operator, door lock circuit, sensors, and mechanical door movement.
6. Relay & Control Circuit Faults
Several TCD codes relate to relays and control circuits.
Examples include:
- · TCD-10 – 50B Relay Pickup Fault
- · TCD-11 – 10T Contactor Pickup Fault
- · TCD-12 – 15B Contactor Pickup/Release Fault
- · TCD-31 – 100R Relay Pickup Fault
- · TCD-42 – 50B Relay Release Fault
These faults often involve relay contacts, contactors, wiring, or control board outputs.
Complete LG Elevator TCD Fault Code Reference
|
Code |
Description |
| TCD-10 | 50B Relay Pickup Fault |
| TCD-11 | 10T Contactor Pickup Fault |
| TCD-12 | 15B Contactor Pickup & Release Fault |
| TCD-13 | Fast/Inspection Mode Input Error |
| TCD-14 | Reference Voltage Fault |
| TCD-15 | Main/Sub Controller Fault |
| TCD-17 | Car Controller Communication Fault |
| TCD-20 | Dual Input Fault |
| TCD-21 | IGBT Short Circuit |
| TCD-22 | DC Bus Overvoltage |
| TCD-23 | Overcurrent |
| TCD-24 | Travel Time Fault |
| TCD-27 | Repeated Fault |
| TCD-31 | 100R Relay Pickup Fault |
| TCD-32/33 | Suppression Circuit Fault |
| TCD-34 | Low Voltage Fault |
| TCD-35 | 40D & 40G Open Circuit |
| TCD-36 | Run Command Fault |
| TCD-37 | Incorrect Travel Direction |
| TCD-40 | Encoder Fault |
| TCD-41 | Inspection Speed Overspeed |
| TCD-42 | 50B Relay Release Fault |
| TCD-43 | Speed Monitoring Fault |
| TCD-46 | Encoder Wiring Fault |
| TCD-50 | High-Speed Overspeed |
| TCD-51 | Speed Variation Fault |
| TCD-60 | Floor Distance Measurement Fault |
| TCD-61 | Position Synchronization Fault (After Power Recovery) |
| TCD-62 | Position Synchronization Fault (Normal Operation) |
| TCD-63 | SDS Connection Fault |
| TCD-64 | SDS Speed Fault |
| TCD-70 | ROM Checksum Fault |
| TCD-73 | Floor Level Sensor (FML) Fault |
| TCD-74 | Multiple Auto Re-leveling Fault |
| TCD-75 | IGBT Heat Sink Overtemperature |
| TCD-76 | Excessive Deceleration Time |
| TCD-77 | Door Operator Overtemperature |
| TCD-80 | Group Communication Fault |
| TCD-81 | COMM Board Communication Fault |
| TCD-83 | Start Compensation Fault |
| TCD-86 | Door Opening Fault |
| TCD-87 | Door Closing Fault |
Conclusion
LG Elevator TCD fault codes provide valuable diagnostic information for maintenance engineers. By understanding the fault category and following a systematic inspection process, technicians can quickly locate the root cause and restore elevator operation efficiently.
YuanQi supplies a comprehensive range of LG elevator spare parts, including controllers, inverters, encoders, sensors, relays, switches, and door system components. We also share practical maintenance knowledge to help elevator professionals improve troubleshooting efficiency and reduce downtime.
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Post time: Jul-29-2026