Allen Bradley PowerFlex 40 Drive Fault Codes List

Complete guide to Allen Bradley PowerFlex 40 fault codes. Troubleshoot common F-codes (F4, F5, F63), use StepLogic diagnostics, and reset the drive using the integral keypad.

PowerFlex 40 Fault Codes Reference Table

Fault Codes	Cause & Solutions
F2 Auxiliary Input	Cause : Auxiliary input interlock is open. Solution: - Check remote wiring. - Verify communications programming for intentional fault.
F3 Power Loss	Cause: Excessive DC Bus voltage ripple. Solution: - Monitor the incoming AC line for low voltage or line power interruption. - Check input fuses. - Reduce load.
F4 UnderVoltage	Cause: DC bus voltage fell below the min value. Solution: Monitor the incoming AC line for low voltage or line power interruption.
F5 OverVoltage	Cause: DC bus voltage exceeded max value. Solution: - Monitor the AC line for high line voltage or transient conditions. - Bus overvoltage can also be caused by motor regeneration. - Extend the decel time or install dynamic brake option.
F6 Motor Stalled	Cause: Drive is unable to accelerate or decelerate motor. Solution: - Increase P039…A067 [Accel Time x] or reduce load so drive output current does not exceed the current set by parameter A089 [Current Limit]. - Check for overhauling load.
F7 Motor Overload	Cause: Internal electronic overload trip. Solution: - An excessive motor load exists. Reduce load so drive output current does not exceed the current set by parameter P033 [Motor OL Current]. - Verify A084 [Boost Select] setting
F8 Heatsink OvrTmp	Cause: Heatsink/Power Module temperature exceeds a predefined value. Solution: - Check for blocked or dirty heatsink fins. Verify that ambient temperature has not exceeded the rated ambient temperature. - Check fan.
F12 HW OverCurrent	Cause: The drive output current has exceeded the hardware current limit. Solution: - Check programming. - Check for excess load, improper A084 [Boost Select] setting, DC brake volts set too high or other causes of excess current.
F13 Ground Fault	Cause: A current path to earth ground has been detected at one or more of the drive output terminals. Solution: - Check the motor and external wiring to the drive output terminals for a grounded condition.
F29 Analog Input Loss	Cause: An analog input is configured to fault on signal loss. - A signal loss has occurred. - Configure with A122 [Analog In Loss]. Solution: 1. Check parameters. 2. Check for broken/loose connections at inputs.
F33 Auto Rstrt Tries	Cause: Drive unsuccessfully attempted to reset a fault and resume running for the programmed number of A092 [Auto Rstrt Tries]. Solution: Correct the cause of the fault and manually clear.
F38 Phase U to Gnd	Cause: A phase to ground fault has been detected between the drive and motor in this phase. Solution: - Check the wiring between the drive and motor. - Check motor for grounded phase. - Replace drive if fault cannot be cleared.
F39 Phase V to Gnd	Cause: A phase to ground fault has been detected between the drive and motor in this phase. Solution: - Check the wiring between the drive and motor. - Check motor for grounded phase. - Replace drive if fault cannot be cleared.
F40 Phase W to Gnd	Cause: A phase to ground fault has been detected between the drive and motor in this phase. Solution: - Check the wiring between the drive and motor. - Check motor for grounded phase. - Replace drive if fault cannot be cleared.
F41 Phase UV Short	Cause: Excessive current has been detected between these two output terminals. Solution: - Check the motor and drive output terminal wiring for a shorted condition. - Replace drive if fault cannot be cleared.
F42 Phase UW Short	Cause: Excessive current has been detected between these two output terminals. Solution: - Check the motor and drive output terminal wiring for a shorted condition. - Replace drive if fault cannot be cleared.
F43 Phase VW Short	Cause: Excessive current has been detected between these two output terminals. Solution: - Check the motor and drive output terminal wiring for a shorted condition. - Replace drive if fault cannot be cleared.
F48 Params Defaulted	Cause: The drive was commanded to write default values to EEPROM. Solution: - Clear the fault or cycle power to the drive. - Program the drive parameters as needed.
F63 SW OverCurrent	Cause: Programmed A098 [SW Current Trip] has been exceeded. Solution: - Verify connections between motor and load. - Check load requirements and A098 [SW Current Trip] setting.
F64 Drive Overload	Cause: Drive overload rating has been exceeded. Drive rating of 150% for 1 minute or 200% for 3 seconds has been exceeded. Solution: Reduce load or extend Accel Time.
F70 Power Unit	Cause: Failure has been detected in the drive power section. Solution: - Check that max ambient temperature has not been exceeded. - Cycle power. - Replace drive if fault cannot be cleared.
F71 Net Loss	Cause: The communication network has faulted. Solution: - Cycle power. - Check communications cabling. - Check network adapter setting. - Check external network status.
F80 SVC Autotune	Cause: The autotune function was either cancelled by the user or failed. Solution: - Restart procedure.
F81 Comm Loss	Cause: RS-485 (DSI) port stopped communicating. Solution: 1. If adapter was not intentionally disconnected, check wiring to the port. Replace wiring, port expander, adapters or complete drive as required. 2. Check connection. 3. An adapter was intentionally disconnected. 4. Turn off using A105 [Comm Loss Action].
F100 Parameter Chksum	Cause: The checksum read from the board does not match the checksum calculated. Solution: Set P041 [Reset To Defalts] to option 1 “Reset Defaults”.
F122 I/O Board Fail	Cause: Failure has been detected in the drive control and I/O section. Solution: - Cycle power. - Replace drive if fault cannot be cleared.

 

How to Read PowerFlex 40 Faults

The PowerFlex 40 offers better diagnostic visibility than the smaller PowerFlex 4. Here is how to access fault data:

• Integral Keypad: The red LED display will flash “F” followed by the fault number (e.g., F…005). The “Fault” status light on the keypad will also flash red.
• Fault History Parameters: You can view the history of the last three faults in the Display Group parameters:
  • d007: Fault 1 (Most Recent)
  • d008: Fault 2
  • d009: Fault 3
• Status LEDs: The PowerFlex 40 has specific LEDs above the display (Run, FWD, REV). If the display is blank but the “Power” LED is off, check the input fuses immediately.
• Software Connection: Like the PF4/4M, the PowerFlex 40 uses the DSI protocol. In 2026, use the 1203-USB converter and Connected Components Workbench (CCW) to download parameters and view the “Fault Buffer” with timestamps (if the drive has been powered continuously).

Frequently Asked Questions (FAQ)

Q: How do I reset a PowerFlex 40 fault?

A: You can reset the drive via:

• The red Stop/Reset button on the keypad.
• Cycling main power (wait for the display to turn off completely).
• A Digital Input configured for “Clear Fault” (Parameters A051-A054 set to option 4).

Q: What is Fault F63 “SW OverCurrent”?

A: This is unique to the PowerFlex 40/400 series. It indicates the drive detected current exceeding the instantaneous hardware limit (usually >200% of rated current). This often happens due to:

• Sudden load impact (mechanical jam).
• Aggressive acceleration times (increase parameter P039).
• A short circuit in the motor wiring.

Q: Can I use “StepLogic” to diagnose issues?

A: Yes. The PowerFlex 40 has internal logic (StepLogic) that acts like a mini-PLC. If your drive is stopping unexpectedly without a fault code, check the StepLogic status in parameter d028 to see if the logic program has commanded the drive to stop or hold zero speed.