Curtis Controller Fault Codes (1234 / 1236 / 1238)
47 fault codes taken directly from the Curtis manual troubleshooting chart — causes, set/clear conditions and the effect on the vehicle. These controllers are used across many electric forklift brands.
| Code | Fault | Possible cause (summary) |
|---|---|---|
| Code 12 | Controller Overcurrent | 1. External short of phase U,V, or W motor connections. 2. Motor parameters are mis-tuned. 3. Controller defec… |
| Code 13 | Current Sensor Fault | 1. Leakage to vehicle frame from phase U, V, or W (short in motor stator). 2. Controller defective.… |
| Code 14 | Precharge Failed | 2. External load on capacitor bank (B+ connection terminal) that prevents the capacitor bank from charging. 1.… |
| Code 15 | Controller Severe Undertemp | 1. See Monitor menu » Controller: Temperature. 2. Controller is operating in an extreme environment.… |
| Code 16 | Controller Severe Overtemp | 1. See Monitor menu » Controller: Temperature. 2. Controller is operating in an extreme environment. 3. Excess… |
| Code 17 | Severe Undervoltage | 1. Battery Menu parameters are misadjusted. 2. Non-controller system drain on battery. 3. Battery resistance t… |
| Code 18 | Severe Overvoltage | 1. See Monitor menu » Battery: Capacitor Voltage. 2. Battery menu parameters are misadjusted. 3. Battery resis… |
| Code 22 | Controller Overtemp Cutback | 1. See Monitor menu » Controller: Temperature. 2. Controller is performance-limited at this temperature. 3. Co… |
| Code 23 | Undervoltage Cutback | 1. Normal operation. Fault shows that the batteries need recharging. Controller is performance limited at this… |
| Code 24 | Overvoltage Cutback | 1. Normal operation. Fault shows that regen braking currents elevated the battery voltage during regen braking… |
| Code 25 | +5V Supply Failure | 1. External load impedance on the +5V supply (pin 26) is too low. 2. See Monitor menu » outputs: 5 Volts and E… |
| Code 26 | Digital Out 6 Overcurrent | 1. External load impedance on Digital Output 6 driver (pin 19) is too low.… |
| Code 27 | Digital Out 7 Overcurrent | 1. External load impedance on Digital Output 7 driver (pin 20) is too low.… |
| Code 28 | Motor Temp Hot Cutback | 1. Motor temperature is at or above the programmed Temperature Hot setting, and the requested current is being… |
| Code 29 | Motor Temp Sensor Fault | 1. Motor thermistor is not connected properly. 2. If the application doesn’t use a motor thermistor, Motor Tem… |
| Code 31 | Coil1 Driver Open/Short | 1. Open or short on driver load. 2. Dirty connector pins. 3. Bad crimps or faulty wiring.… |
| Code 32 | Coil2 Driver Open/Short | 1. Open or short on driver load. 2. Dirty connector pins. 3. Bad crimps or faulty wiring.… |
| Code 33 | Coil3 Driver Open/Short | 1. Open or short on driver load. 2. Dirty connector pins. 3. Bad crimps or faulty wiring.… |
| Code 34 | Coil4 Driver Open/Short | 1. Open or short on driver load. 2. Dirty connector pins. 3. Bad crimps or faulty wiring.… |
| Code 35 | PD Open/Short | 1. Open or short on driver load. 2. Dirty connector pins. 3. Bad crimps or faulty wiring.… |
| Code 36 | Encoder Fault | 1. Motor encoder failure. 2. Bad crimps or faulty wiring. 3. See Monitor menu » Motor: Motor RPM.… |
| Code 37 | Motor Open | 1. Motor phase is open. 2. Bad crimps or faulty wiring.… |
| Code 38 | Main Contactor Welded | 1. Main contactor tips are welded closed. 2. Motor phase U or V is disconnected or open. 3. An alternate volta… |
| Code 39 | Main Contactor Did Not Close | 1. Main contactor did not close. 2. Main contactor tips are oxidized, burned, or not making good contact. 3. E… |
| Code 41 | Throttle Wiper High | 1. See Monitor menu » Inputs: Throttle Pot. 2. Throttle pot wiper voltage too high.… |
| Code 42 | Throttle Wiper Low | 1. See Monitor menu » Inputs: Throttle Pot. 2. Throttle pot wiper voltage too low.… |
| Code 43 | Pot2 Wiper High | 1. See Monitor menu » Inputs: Pot2 Raw. 2. Pot2 wiper voltage too high.… |
| Code 44 | Pot2 Wiper Low | 1. See Monitor menu » Inputs: Pot2 Raw. 2. Pot2 wiper voltage too low.… |
| Code 45 | Pot Low Overcurrent | 1. See Monitor menu » Outputs: Pot Low. 2. Combined pot resistance connected to pot low is too low.… |
| Code 46 | EEPROM Failure | 1. Failure to write to EEPROM memory. This can be caused by EEPROM memory writes initiated by VCL, by the CAN … |
| Code 47 | HPD/Sequencing Fault | 1. KSI, interlock, direction, and throttle inputs applied in incorrect sequence. 2. Faulty wiring, crimps, or … |
| Code 49 | Parameter Change Fault | 1. This is a safety fault caused by a change in certain parameter settings so that the vehicle will not operat… |
| Code 68 | VCL Run Time Error | 1. VCL code encountered a runtime VCL error. 2. See Monitor menu » Controller: VCL Error Module and VCL Error.… |
| Code 69 | External Supply Out of Range | 1. External load on the 5V and 12V supplies draws either too much or too little current. 2. Fault Checking Men… |
| Code 71 | OS General | 1. Internal controller fault.… |
| Code 72 | PDO Timeout | 1. Time between CAN PDO messages received exceeded the PDO Timeout Period.… |
| Code 73 | Stall Detected | 1. Stalled motor. 2. Motor encoder failure. 3. Bad crimps or faulty wiring. 4. Problems with power supply for … |
| Code 74 | Fault On Other Traction | Dual Drive fault: see Dual Drive manual.… |
| Code 75 | Dual Severe Fault | Dual Drive fault: see Dual Drive manual.… |
| Code 87 | Motor Characterization Fault | 1. Motor characterization failed during characterization process. See Monitor menu » Controller: Motor Charact… |
| Code 89 | Motor Type Fault | 1. The Motor_Type parameter value is out of range.… |
| Code 91 | VCL/OS Mismatch | 1. The VCL software in the controller does not match the OS software in the controller.… |
| Code 92 | EM Brake Failed to Set | 1. Vehicle movement sensed after the EM Brake has been commanded to set. 2. EM Brake will not hold the motor f… |
| Code 93 | Encoder LOS (Limited | 1. Limited Operating Strategy (LOS) control mode has been activated, as a result of either an Encoder Fault (C… |
| Code 94 | Emer Rev Timeout | 1. Emergency Reverse was activated and concluded because the EMR Timeout timer has expired. 2. The emergency r… |
| Code 98 | Illegal Model Number | 1. Model_Number variable contains illegal value (not 1234, 1236, 1238, or 1298). 2. Software and hardware do n… |
| Code 99 | Dualmotor Parameter Mismatch | Dual Drive fault: see Dual Drive manual.… |
Source: Curtis 1234/36/38 Controller Manual, OS 11, Table 5 Troubleshooting Chart.