The table below deals with troubleshooting any Liftmaster gate opener. It will be of great help no matter whether you are an experienced technician or it is just your first attempt at electric gate opener repair. You will need a couple of basic tools and enough patience to follow all safety rules when working with electricity.
| FAULT | POSSIBLE CAUSE | FIX |
| OPERATOR IS DEAD No LED lights are on. | 1) No voltage to board. | Battery must be >23 V, AC or needs to be connected. |
| 2) Bad control board. | Replace control board. | |
| OPERATOR DOES NOT RUN. Operator does not respond to any commands. | 1) Low/disconnected battery. | Voltage must be >23 V at battery connection. |
| 2) Remote not programmed. | Program | |
| 3) STOP connection loose/disconnected. | Check STOP connections. | |
| 4) Constant Open Command (Check LED's). | Clear all Open/Safety devices from obstruction. | |
| 5) Limits not programmed correctly. | ||
| 6) Bad control board. | Replace control board. | |
| MOTOR DOES NOT RUN. Relays "dirk" when radio or SBC signal is given, but the operator does not move. | 1) Low Battery. | Voltage must be >23 V at battery connection. |
| 2) Cable wiring between control box and operator arm disconnected or loose. | Check wiring on control board to arm, replace wire if needed. | |
| 3) Batteries not connected. | Connect batteries. | |
| 4) Bad motor. | Replace motor. | |
| 5) Bad control board. | Replace control board. | |
| GATE STOPS AND REVERSES (Forte Reversal) | 1) Gale met an obstruction. | Clear gate from obstruction. |
| 2) Force set loo low. | ||
| 3) Bad gale hardware. | Service/replace gate hardware. | |
| 4) Incorrect Arm installation. | ||
| RPM REVERSAL | 1) Obstructed Arm (bottoms out). | Check for obstruction on arm, verify arm is not bottomed out. |
| 2) Bad RPM Sensor. | Replace arm. | |
| 3) Too much mA pulled off board. | Move accessories to separate power source. | |
| GATE STOPS. Gale starts to run, then stops and does not reverse. | 1) Low battery. | Voltage must be >23 V at battery connection. |
| 2) Gale met an obstruction. | Clear gate from obstruction. | |
| GATE OPENS BUT DOES NOT CLOSE | 1) Constant Open Command (Check LED's). | Clear all Open/Safety devices from obstruction. |
| 2) Timer-to-Close not set. | Adjust the Timer-to-Close | |
| 3) Accessory device wired to Open Only command | Rewire desired accessory device to Single Button Input. | |
| Audible beeps (3 times) when command is given. | 1) Battery Low >23.5 V | Operator will resume normal operation once battery voltage reaches 24 V. |
| GATE'S DO NOT OPEN/ CLOSE IN SYNC | 1) Bipart Delay not set. | Set |
| 2) Limits not programmed correctly. | ||
| 3) Incorrect Arm Installation | Incorrect Arm Installation. Please reinstall | |
| GATE DOES NOT AUTOMATICALLY CLOSE Auto Close Timer not closing gate. | 1) Timer-to-Close not turned on. | Adjust the Timer-to-Close |
| 2) Gate has opened on Obstruction Reversal. | Check DIAG code, deor obstruction. | |
| 3) Operator in "Party Mode". | Use remote control/SBC to resume normal operation | |
| 4) Constant Open Command (Check LED's). | Clear all Open/Safety devices from obstruction. | |
| ACCESSORY DEVICE NOT WORKING PROPERLY | 1) Not installed properly. | Check for proper installation of accessory. |
| 2) Enabling Switch not turned on. | Turn applicable switches on. | |
| 3) Loose/disconnected wires. | Check proper installation of wires. | |
| 4) Bad accessory device | Replace accessory device. |
Liftmaster manufactures a variety of telephone entry systems, gate operators, and access control systems, as well as related products both for commercial and residential purposes. It is a well-known brand that is quintessentially American. Liftmaster is based in Elmhurst, Illinois.