ABB ACH180 Drive Fault Codes List

Access the complete reference guide for ABB ACH180 HVAC micro drive fault codes. Learn to diagnose OEM errors via the Drivetune App and Drive Composer.

The ABB ACH180 is a compact “Micro Drive” specifically engineered for HVACR OEMs (Heating, Ventilation, Air Conditioning, and Refrigeration). Unlike the larger ACH580, this drive is designed for cost-effective integration into air handlers, pumps, and fans. When it trips, the standard icon-based panel displays a 4-digit code (often starting with F-) or specific icon indicators.

This guide provides the most updated reference to help you interpret these codes and maintain efficient building climate control.

ACH180 Fault Codes Reference Table

Use the search bar below or browse the table to identify your specific error code:

Fault Code  Cause & Solution
1080
Backup/Restore
timeout		 Cause: Panel or PC tool has failed to communicate with the drive when backup was being made or restored.

Solution:

Request backup or restore again.
1081
Rating ID
fault 		 Cause: Drive software has not been able to read the rating ID of the drive.

Solution:

1. Reset the fault to make the drive try to reread the rating ID.
2. If the fault reappears, cycle the power to the drive. You may have to be repeat this. If the fault persists, need to repair or replace drive.
2281
Calibration		 Cause: Measured offset of output phase current measurement or difference between output phase U2 and W2 current measurement is too great (the values are updated during current calibration).

Solution:

1. Try performing the current calibration again.
2. If problem not resolved then need to repair or replace drive.
2310
Overcurrent		 Cause: Output current has exceeded internal fault limit. In addition to an actual overcurrent situation, this fault may also be caused by an earth fault or supply phase loss.

Solution:

1. Check motor load.
2. Check acceleration times in parameter group 23 Speed reference ramp (speed control), 26 Torque reference chain (torque control) or 28 Frequency reference chain (frequency control).
3. Also check parameters 46.01 Speed scaling, 46.02 Frequency scaling and 46.03 Torque scaling.
4. Check motor and motor cable (including phasing and delta/star connection).
5. Check there are no contactors opening and closing in motor cable.
6. Check that the start-up data in parameter group 99 Motor data corresponds to the motor rating plate.
7. Check that there are no power factor correction capacitors or surge absorbers in motor cable.
8. Check for an earth fault in motor or motor cables by measuring the insulation resistances of motor and motor cable.
2330
Earth leakage		 Cause: Drive has detected load unbalance typically due to earth fault in motor or motor cable.

Solution:

1. Check there are no power factor correction capacitors or surge absorbers in motor cable.
2. Check for an earth fault in motor or motor cables by measuring the insulation resistances of motor and motor cable.
3. Try running the motor in scalar control mode if allowed. (See parameter 99.04 Motor control mode.)
4. After this if problem not resolved then need to repair or replace drive.
2340
Short circuit 		 Cause: Short-circuit in motor cable(s) or motor. Aux code 0x0080 indicates that the state feedback from output phases does not match the control signals.

Solution:

1. Check motor and motor cable for cabling errors.
2. Check there are no power factor correction capacitors or surge absorbers in motor cable.
3. Cycle the power to the drive.
2381
IGBT overload		 Cause: Excessive IGBT junction to case temperature. This fault protects the IGBT(s) and can be activated by a short circuit in the motor cable.

Solution:

1. Check motor cable.
2. Check ambient conditions.
3. Check air flow and fan operation.
4. Check heatsink fins for dust pick-up.
5. Check motor power against drive power.
3130
Input phase
loss 		 Cause: Intermediate circuit DC voltage is oscillating due to missing input power line phase or blown fuse.

Solution:

1. Check input power line fuses.
2. Check for loose power cable connections.
3. Check for input power supply imbalance.
3181
Cross connection		 Cause: Incorrect input power and motor cable connection (ie. input power cable is connected to drive motor connection).

Solution:

1. Check input power connections.
3210
DC link
overvoltage 		 Cause: Excessive intermediate circuit DC voltage.

Solution:

1. Check that overvoltage control is on (parameter 30.30 Overvoltage control).
2. Check that the supply voltage matches the nominal input voltage of the drive.
3. Check the supply line for static or transient overvoltage.
4. Check deceleration time. Use coast-to-stop function (if applicable).
5. Retrofit drive with brake chopper and brake resistor.
6. Check that the brake resistor is dimensioned properly and the resistance is between acceptable range for the drive.
3220
DC link
undervoltage 		 Cause: Intermediate circuit DC voltage is not sufficient because of a missing supply phase, blown fuse or fault in the rectifier bridge.

Solution:

1. Check supply cabling, fuses and switchgear.
3385
Autophasing 		 Cause: Autophasing routine has failed.

Solution:

1. Check that the motor ID run has been successfully completed.
2. Check that the motor is not already turning when the autophasing routine starts.
3. Check the setting of parameter 99.03 Motor type.
3381
Output phase
loss		 Cause: Motor circuit fault due to missing motor connection (any of the three phases not connected).
In scalar control mode, the drive detects fault only when the output frequency is above 10% of the motor nominal frequency.


Solution:

1. Connect motor cable.
2. If the drive is in scalar mode and nominal current of the motor is less than 1/6 of the nominal output current of the drive, set parameter 31.19 Motor phase loss to No action.
4110
Control board
temperature		 Cause: Control board temperature is too high.

Solution:

1. Check proper cooling of the drive.
2. Check the auxiliary cooling fan.
4210
IGBT
overtemperature		 Cause: Estimated drive IGBT temperature is excessive.

Solution:

1. Check air flow and fan operation.
2. Check heatsink fins for dust pick-up.
3. Check motor power against drive power.
4. Check ambient conditions.
4290
Cooling 		 Cause: Drive module temperature is excessive.

Solution:

1. Check ambient temperature. If it exceeds 50 °C /122 °F, ensure that load current does not exceed derated load capacity of drive.
2. Check drive module cooling air flow and fan operation.
3. Check inside of cabinet and heatsink of drive module for dust pick-up. Clean  whenever necessary.
42F1
IGBT
temperature 		 Cause: Drive IGBT temperature is excessive.

Solution:

1. Check ambient conditions.
2. Check air flow and fan operation.
3. Check heatsink fins for dust pick-up.
4. Check motor power against drive power.
4310
Excess
temperature 		 Cause: Power unit module temperature is excessive.

Solution:

1. Check ambient conditions.
2. Check air flow and fan operation.
3. Check heatsink fins for dust pick-up.
4. Check motor power against drive power.
4180
Excess
temperature
difference		 Cause: High temperature difference between the IGBTs of different phases.

Solution:

1. Check the motor cabling.
2. Check cooling of drive module(s).
4981
External
temperature 1		 Cause: Measured temperature 1 has exceeded fault limit.

Solution:

1. Check the value of parameter 35.02 Measured temperature 1.
2. Check the cooling of the motor (or other equipment whose temperature is being measured).
3. Check the value of parameter 35.12 Temperature 1 fault limit.
5080
Fan		 Cause: Cooling fan stuck or disconnected.

Solution:

1. Check fan operation and connection.
2. Replace fan if faulty.
5090
STO hardware
failure		 Cause: STO hardware diagnostics has detected hardware failure.


Solution: There is an hardware issue in drive. Need to repair or replace drive.
5091
Safe
torque off		 Cause: Safe torque off function is active, ie. safety circuit signal(s) connected to connector STO is broken during start or run.

Solution:

1. Check safety circuit connections.
2. This is a Programmable fault: check parameter 31.22 STO indication run/stop.
5092
PU logic
error 		 Cause: Power unit memory has cleared.

Solution: There is an hardware or software issue in drive. Need to repair or replace drive.
5093
Rating ID
mismatch 		 Cause: The hardware of the drive does not match the information stored in the memory. This may occur eg. after a firmware update.

Solution:

1. Cycle the power to the drive.
2. You may have to be repeat this.
3. If fault not resolved after this then need to repair or replace drive.
5094
Measurement
circuit
temperature		 Cause: Problem with internal temperature measurement of the drive.

Solution: There is an hardware or software issue in drive. Need to repair or replace drive.

5098
I/O
communication
loss		 Cause: Communication failure to standard I/O.

Solution: Try resetting the fault or cycle the power to the drive.
5681
PU
communication 		 Cause: Communication errors detected between the drive control unit and the power unit.

Solution: Check the connection between the drive control unit and the power unit.
5690
PU communication
internal		 Cause: Internal communication error.

Solution: There is an hardware or software issue in drive. Need to repair or replace drive.
5691
Measurement
circuit ADC		 Cause: Measurement circuit fault.

Solution: There is an hardware or software issue in drive. Need to repair or replace drive.
5692
PU board
powerfail 		 Cause: Power unit power supply failure.

Solution: There is an hardware or software issue in drive. Need to repair or replace drive.
5693
Measurement
circuit DFF		 Cause: Measurement circuit fault.

Solution: There is an hardware or software issue in drive. Need to repair or replace drive.
5697
Charging
feedback 		 Cause: Charging feedback signal missing.

Solution: Check the feedback signal coming from the charging system.
6181
FPGA version
incompatible		 Cause: Firmware and FPGA versions are incompatible.

Solution:

1. Reboot the control unit (using parameter 96.08 Control board boot) or by cycling power.
2. After this same problem comes then need to repair or replace drive.
6200
Checksum
mismatch		 Cause: The calculated parameter checksum does not match any enabled reference checksum.

Solution: This is a Programmable event: check parameter 96.54 Checksum action
6481
Task
overload 		 Cause: Internal fault. There is an internal issue in drive

Solution:

1. Reboot the control unit (using parameter 96.08 Control board boot) or by cycling power.
2. After this same problem then need to repair or replace drive.
6487
Stack overflow		 Cause: Internal fault. There is an internal issue in drive

Solution:

1. Reboot the control unit (using parameter 96.08 Control board boot) or by cycling power.
2. After this same problem then need to repair or replace drive.
64A1
Internal
file load 		 Cause: File read error. There is an internal issue in drive

Solution:

1. Reboot the control unit (using parameter 96.08 Control board boot) or by cycling power.
2. After this same problem then need to repair or replace drive.
64A6
Adaptive program
file incompatible
or corrupted		 Cause: Adaptive program has faulted.

Solution:

Check the auxiliary code. See actions for each code below.

000A Program corrupted or block non-existent. Restore the template program or download the program to the drive.

000C Required block input missing. Check the inputs of the block.

000E Program corrupted or block non-existent. Restore the template program or download the program to the drive.

0011 Program too large. Remove blocks until the error stops.

0012 Program is empty. Correct the program and download it to the drive.

001C A non-existing parameter or block is used in the parameter. Edit the program to correct the parameter reference, or use an existing block.

001E Output to parameter failed because the parameter was write-protected. Check the parameter reference in the program. Check for other sources responsible the target parameter.

0023 Program file incompatible with current firmware version. Adapt the program to current block library and firmware version.

0024 Program file incompatible with current firmware version. Adapt the program to current block library and firmware version
64B1
Internal SSW
fault		 Cause: Internal fault. There is an software or hardware issue in drive.

Solution:

1. Reboot the control unit (using parameter 96.08 Control board boot)or by cycling power.
2. If problem not resolve after this then need to repair or replace drive.
64B2
User set
fault 		 Cause: Loading of user parameter set failed because
• requested set does not exist
• set is not compatible with control program
• drive was switched off during loading.

Solution: Ensure that a valid user parameter set exists. Reload if uncertain.
64E1
Kernel
overload		 Cause: Operating system error.

Solution:

1. Reboot the control unit(using parameter 96.08 Control board boot) or by cycling power.
2. After this same problem then need to repair or replace drive.
64FF
Fault reset		 Cause: A fault has been reset from the panel, Drive composer PC tool, fieldbus or I/O.
Solution: This is an Informative only.
6581
Parameter
system 		 Cause: Parameter load or save failed.

Solution: Try forcing a save using parameter 96.07 Parameter save manually. Retry.
6591
Backup/Restore
timeout		 Cause: Parameter load or save timeout caused by communication break between drive and control panel, or control panel and PC tool.


Solution: Check the communication between drive and control panel or PC. Retry.
6681
EFB comm
loss		 Cause: Communication break in embedded fieldbus (EFB) communication.

Solution:

1. Check the status of the fieldbus master (online/offline/error etc.).
2. Check cable connections to the EIA-485 terminals 25, 26, 27 and 28 on the control unit.
3. This is a Programmable fault: check parameter 58.14 Communication loss action.
6682
EFB config
file 		 Cause: Embedded fieldbus (EFB) configuration file could not be read.

Solution: There is an hardware or software issue in drive. Need to repair or replace drive.
6683
EFB invalid
parameterization		 Cause: Embedded fieldbus (EFB) parameter settings inconsistent or not compatible with selected protocol.

Solution: Check the settings in parameter group 58 Embedded fieldbus.
6684
EFB load
fault 		 Cause: Embedded fieldbus (EFB) protocol firmware could not be loaded or version mismatch between EFB protocol firmware and drive firmware.

Solution: There is an hardware or software issue in drive need to repair or replace drive.
6685
EFB fault 2 		 Cause: Fault reserved for the EFB protocol application.

Solution: Check the documentation of the protocol.
6686
EFB fault 3 		 Cause: Fault reserved for the EFB protocol application.

Solution: Check the documentation of the protocol.
6882
Text 32-bit
table overflow		 Cause: Internal fault.

Solution: Reset the fault. If fault not reset then need to repair or replace drive.
6885
Text file
overflow		 Cause: Internal fault.

Solution: Reset the fault. If fault not reset then need to repair or replace drive.
7081
Control panel
loss		 Cause: Control panel or PC tool selected as active control location for drive has ceased communicating.

Solution:

1. Check PC tool or control panel connection.
2. Check control panel connector.
3. Disconnect and reconnect the control panel.
4. This is a Programmable fault: check parameter 49.05 Communication loss action.
7086
I/O module
AI Over
voltage		 Cause: Overvoltage detected in AI. AI is changed to voltage mode. AI will return automatically back to mA mode when the AI signal level is in accepted limits.

Solution: Check AI signal levels.
7121
Motor stall		 Cause: Motor is operating in stall region because of e.g. excessive load or insufficient motor power.

Solution:

1. Check motor load and drive ratings.
2. Check fault function parameters.
7122
Motor
overload 		 Cause: Motor current is too high.

Solution:

1. Check the motor, and the machinery coupled to motor, for overload.

2. Adjust the parameters used for the motor overload function ( 35.51…35.53) and 35.55…35.56.
7181
Brake resistor		 Cause: Brake resistor broken or not connected.

Solution:

1. Check that a brake resistor has been
connected.heck the condition of the brake
resistor.
2. Check the dimensioning of the brake
resistor.
7183
BR excess
temperature		 Cause: Brake resistor temperature has exceeded fault limit defined by parameter 43.11 Brake resistor fault limit.

Solution:

Stop drive.
Let resistor cool down.
Check resistor overload protection function settings (parameter group 43 Brake chopper).
Check fault limit setting, parameter 43.11 Brake resistor fault limit.
Check that braking cycle meets allowed limits.
7184
Brake resistor
wiring		 Cause: Brake resistor short circuit or brake chopper control fault.

Solution:

1. Check brake chopper and brake resistor connection.
2. Ensure brake resistor is not damaged.
7191
BC short
circuit		 Cause: Short circuit in brake chopper IGBT.

Solution:

1. Ensure brake resistor is connected and not damaged.
2. Check the electrical specifications of the brake resistor.
7192
BC IGBT
excess temp		 Cause: Brake chopper IGBT temperature has exceeded internal fault limit.

Solution:

1. Let chopper cool down.Check for excessive ambient temperature.
2. Check for cooling fan failure.
3. Check for obstructions in the air flow.
4. Check the dimensioning and cooling of the cabinet.
5. Check that braking cycle meets allowed limits.
6. Check that drive supply AC voltage is not excessive.
7310
Overspeed 		 Cause: Motor is turning faster than highest allowed speed due to incorrectly set minimum/maximum speed, insufficient braking torque or changes in load when using torque reference.

Solution:

1. Check minimum/maximum speed settings, parameters 30.11 Minimum speed and 30.12 Maximum speed.
2. Check adequacy of motor braking torque.
3. Check applicability of torque control.
4. Check need for brake chopper and resistor(s).
73B0
Emergency
ramp failed		 Cause: Emergency stop did not finish within expected time.

Solution:

1. Check the settings of parameters 31.32 Emergency ramp supervision and 31.33 Emergency ramp supervision delay.
2. Check the predefined ramp times (23.11…23.15 for mode Off1, 23.23 for mode Off3).
73F0
Overfrequency 		 Cause: Maximum allowed output frequency exceeded.

Solution:

1. Check minimum/maximum frequency settings, parameters 30.13 Minimum frequency and 30.14 Maximum frequency.
2. Check adequacy of motor braking torque.
3. Check applicability of torque control.
4. Check need for brake chopper and resistor(s).
8001
ULC
underload
fault 		 Cause: User load curve- Signal has been too long under the underload curve.

Solution: See parameter 37.04 ULC underload actions.
8002
ULC overload
fault 		 Cause: User load curve: Signal has been too long over the overload curve.

Solution: See parameter 37.03 ULC overload actions.
80A0
AI supervision		 Cause: An analog signal is outside the limits specified for the analog input.

Solution:

1. Check signal level at the analog input.
2. Check the wiring connected to the input.
3. Check the minimum and maximum limits of the input in parameter group 12 Standard AI.
4. This is a Programmable fault: check parameter 12.03 AI supervision function.
80B0
Signal
supervision		 Cause: Fault generated by the signal supervision 1 function.

Solution:

1. Check the source of the fault (parameter 32.07 Supervision 1 signal).
2. This is a Programmable fault: check parameter 32.06 Supervision 1 action
80B1
Signal
supervision		 Cause: Fault generated by the signal supervision 2 function.

Solution:

1. Check the source of the fault (parameter 32.17 Supervision 2 signal).
2. This is a Programmable fault: check parameter 32.16 Supervision 2 action
80B2
Signal
supervision		 Cause: Fault generated by the signal supervision 3 function.

Solution:

1. Check the source of the fault (parameter32.27 Supervision 3 signal).
2. This is a Programmable fault: check parameter 32.26 Supervision 3 action
80B3
Signal
supervision		 Cause: Fault generated by the signal supervision 4 function.

Solution:

1. Check the source of the fault (parameter 32.37 Supervision 4 signal).
2. This is a Programmable fault: check parameter 32.36 Supervision 4 action
80B4
Signal
supervision		 Cause: Fault generated by the signal supervision 5 function.

Solution:

1. Check the source of the fault (parameter 32.47 Supervision 5 signal).
2. This is a Programmable fault: check parameter 32.46 Supervision 5 action
80B5
Signal
supervision		 Cause: Fault generated by the signal supervision 6 function.

Solution:

1. Check the source of the fault (parameter 32.57 Supervision 6 signal).
2. This is a Programmable fault: check parameter 32.56 Supervision 6 action
9081
External
fault 1		 Cause: Fault in external device 1.

Solution:

Check the external device.
Check setting of parameter 31.01 External event 1 source.
This is a Programmable fault: check parameter 31.01 External event 1 source 31.02 External event 1 type.
9082
External
fault 2		 Cause: Fault in external device 2.

Solution:

Check the external device.
Check setting of parameter 31.03 External event 2 source.
This is a Programmable fault: check parameter 31.03 External event 2 source 31.04 External event 2 type.
9083
External
fault 3		 Cause: Fault in external device 3.

Solution:

Check the external device.
Check setting of parameter 31.05 External event 3 source.
This is a Programmable fault: check parameter 31.05 External event 3 source 31.06 External event 3 type.
9084
External
fault 4		 Cause: Fault in external device 4.

Solution:

Check the external device.
Check setting of parameter 31.07 External event 4 source.
This is a Programmable fault: check parameter 31.07 External event 4 source 31.08 External event 4 type.
9085
External
fault 5		 Cause: Fault in external device 5.

Solution:

Check the external device.
Check setting of parameter 31.09 External event 5 source.
This is a Programmable fault: check parameter 31.09 External event 5 source 31.10 External event 5 type.
A2A1
Current calibration 		 Cause: Current offset and gain measurement calibration will occur at next start.

Solution: This is an Informative warning. (See parameter 99.13 ID run requested.)
A2B1
Overcurrent 		 Cause: Output current has exceeded internal fault limit. In addition to an actual overcurrent situation, this warning may also be caused by an earth fault or supply
phase loss.

Solution:

1. Check motor load.
2. Check acceleration times in parameter group
23 Speed reference ramp (speed control),
26 Torque reference chain (torque control) or
28 Frequency reference chain (frequency control).
3. Also check parameters 46.01 Speed scaling,
46.02 Frequency scaling and
46.03 Torque scaling.
4.Check motor and motor cable (including phasing and delta/star connection).
5. Check for an earth fault in motor or
motor cables by measuring the insulation resistances of motor and motor cable. See chapter Electrical installation, section
6. Checking the insulation of the assembly in the hardware manual of the drive.
7. Check there are no contactors opening
and closing in motor cable.
8. Check that the start-up data in parameter group 99 Motor data corresponds to the motor rating plate.
9. Check that there are no power factor
correction capacitors or surge absorbers in motor cable.
A2B3
Earth leakage 		 Cause: Drive has detected load unbalance typically due to earth fault in motor or motor cable.

Solution

1. Check there are no power factor correction capacitors or surge absorbers in motor cable.
2. Check for an earth fault in motor or motor cables by measuring the insulation resistances of motor and motor cable.
3. Check the insulation of the assembly in the hardware manual of the drive. If an earth fault is found, fix or change the motor cable and/or motor.
4. If no earth fault can be detected then hardware issue in drive.
A2B4
Short circuit		 Cause: Short-circuit in motor cable(s) or motor.

Solution:

1. Check motor and motor cable for cabling errors.
2. Check motor and motor cable (including phasing and delta/star connection).
3. Check for an earth fault in motor or motor cables by measuring the insulation resistances of motor and motor cable.
4. Check there are no power factor correction capacitors or surge absorbers in motor cable.
A2BA
IGBT overload 		 Cause: Excessive IGBT junction to case temperature. This warning protects the IGBT(s) and can be activated by a short circuit in the motor cable.

Solution:

1. Check motor cable.
2. Check ambient conditions.
3. Check air flow and fan operation.
4. Check heatsink fins for dust pick-up.
5. Check motor power against drive power.
A3A1
DC link overvoltage 		 Cause: Intermediate circuit DC voltage too high (when the drive is stopped).

Solution:

1. Check the supply voltage setting (parameter 95.01 Supply voltage).
Note that the wrong setting of the parameter may cause the motor to rush uncontrollably, or may overload the brake chopper or resistor.
2. Check the supply voltage.
3. If the problem persists, then hardware issue in drive or other issue in drive.
A3A2
DC link undervoltage 		 Cause: Intermediate circuit DC voltage too low (when the drive is stopped).

Solution:

1. Check the supply voltage setting (parameter 95.01 Supply voltage).
Note that the wrong setting of the parameter may cause the motor to rush uncontrollably, or may overload the brake chopper or resistor.
2. Check the supply voltage.
3. If the problem persists, then hardware issue in drive or other issue in drive.
A3AA
DC not charged 		 Cause: The voltage of the intermediate DC circuit has not yet risen to operating level.

Solution:

1. Check the supply voltage setting (parameter 95.01 Supply voltage).
Note that the wrong setting of the parameter may cause the motor to rush uncontrollably, or may overload the brake chopper or resistor.
2. Check the supply voltage.
3. If the problem persists, then hardware issue in drive or other issue in drive.
A490
Incorrect temperature
sensor setup		 Cause: Sensor type mismatch.

Solution: Check the settings of temperature source parameters 35.11.
A491
External temperature 1		 Cause: Measured temperature 1 has exceeded warning limit.

Solution

1. Check the value of parameter 35.02 Measured temperature 1.
2. Check the cooling of the motor (or other equipment whose temperature is being measured).
3. Check the value of 35.13 Temperature 1 warning limit.
A4A1
IGBT
overtemperature		 Cause: Estimated drive IGBT temperature is excessive.

Solution:

1. Check ambient conditions.
2. Check air flow and fan operation.
3. Check heatsink fins for dust pick-up.
4. Check motor power against drive power.
A4A9
Cooling 		 Cause: Drive module temperature is excessive.

Solution:

1. Check ambient temperature. If it exceeds 50 °C /122 °F, ensure that load current does not exceed derated load capacity of drive.
2. Check drive module cooling air flow and fan operation.
3. Check inside of cabinet and heatsink of drive module for dust pick-up. Clean whenever necessary.
A4B0
Excess
temperature 		 Cause: Power unit module temperature is excessive.

Solution:

Check ambient conditions.
Check air flow and fan operation.
Check heatsink fins for dust pick-up.
Check motor power against drive power.
A4B1
Excess temperature
difference		 Cause: High temperature difference between the IGBTs of different phases.

Solution:

1. Check the motor cabling.
2. Check cooling of drive module(s).
A4F6
IGBT temperature		 Cause: Drive IGBT temperature is excessive.

Solution:

Check ambient conditions.
Check air flow and fan operation.
Check heatsink fins for dust pick-up.
Check motor power against drive power.
A5A0
Safe torque off		 Cause: Safe torque off function is active, ie safety circuit signal(s) connected to connector STO is lost.

Solution:

1. Check safety circuit connections.
2. Check parameter 31.22 STO indication run/stop.
A5EA
Measurement circuit
temperature		 Cause: Problem with internal temperature measurement of the drive.

Solution:

1. Check drive hardware.
2. May be hardware issue in drive.
A5EB
PU board
powerfail 		 Cause: Power unit power supply failure.

Solution:

1. Check drive hardware.
2. May be hardware issue in drive.
A5ED
Measurement
circuit ADC		 Cause: Measurement circuit fault.

Solution:

1. Check drive hardware.
2. May be hardware issue in drive.
A5EE
Measurement
circuit DFF		 Cause: Measurement circuit fault.

Solution:

1. Check drive hardware.
2. May be hardware issue in drive.
A5EF
PU state
feedback		 Cause: State feedback from output phases does not match control signals.

Solution:

1. Check drive hardware.
2. May be hardware issue in drive.
A5F0
Charging feedback 		 Cause: Charging feedback signal missing.

Solution:

1. Check the feedback signal coming from the charging system.
A686
Checksum mismatch		 Cause: The calculated parameter checksum does not match any enabled reference checksum.

Solution:

1. Check that all necessary approved (reference) checksums (96.71…96.72) are enabled in 96.55 Checksum control word.
2. Check the parameter configuration. Using
96.55 Checksum control word, enable a checksum parameter and copy the actual checksum into that parameter.
3. This is programmable warning check parameter "Programmable warning: 96.54 Checksum action".
A6A4
Motor nominal
value		 Cause: The motor parameters are set incorrectly. The drive is not dimensioned
correctly.

Solution:

1. Check the settings of the motor configuration parameters in group 99.
2. Check that the drive is sized correctly for the motor.
A6A5
No motor data 		 Cause: Parameters in group 99 have not been set.


Solution:

1. Check that all the required parameters in group 99 have been set.

Note: It is normal for this warning to appear during the start-up and continue until the motor data is
entered.
A6A6
Voltage category
unselected		 Cause: The voltage category has not been defined.


Solution: Set voltage category in parameter 95.01 Supply voltage.
A6B0
User lock
is open		 Cause: The user lock is open, ie. user lock configuration parameters 96.100… 96.102 are visible.


Solution: Close the user lock by entering an invalid pass code in parameter 96.02 Pass code.
A6B1
User pass
code not
confirmed		 Cause: A new user pass code has been entered in parameter 96.100 but not confirmed in 96.101.


Solution: Confirm the new pass code by entering the same code in 96.101. To cancel, close the user lock without confirming the new code.
A6E5
AI parametrization 		 Cause: The current/voltage hardware setting of an analog input does not correspond to parameter settings.


Solution:

1. Check the event log for an auxiliary code. The code identifies the analog input whose settings are in conflict. Adjust parameter 12.15/ 12.25.

Note: Control board reboot (either by cycling the power or through parameter 96.08 Control board boot) is required to validate any changes in the hardware settings.
A6E6
ULC configuration 		 Cause: User load curve configuration error.


Solution: Check the auxiliary code. See actions
for each code below.

0000 - Speed points inconsistent. Check that each speed point (parameters 37.11… 37.15) has a higher value than the previous point.

0001 - Frequency points inconsistent. Check that each frequency point (37.16… 37.20) has a higher value than the previous point.

0002 - Underload point above overload point. Check that each overload point (37.31…37.35) has a higher value than the corresponding underload point (37.21… 37.25).

0003 - Overload point below underload point. Check that each overload point (37.31…37.35) has a higher value than the corresponding underload point (37.21… 37.25).
A780
Motor stall		 Cause: Motor is operating in stall region because of e.g. excessive load or insufficient motor power.


Solution:

1. Check motor load and drive ratings.
2. Check fault function parameters.
3. This is a programmable warning check parameter 31.24 Stall function.
A783
Motor overload		 Cause: Motor current is too high.

Solution:

1. Check the motor, and the machinery coupled to motor, for overload.
2. Adjust the parameters used for the motor overload function (35.51…35.53) and 35.55…35.56.
A784
Motor disconnect 		 Cause: All three output phases are disconnected from motor.

Solution:

1. Check if parameter 95.26 enables the use of a motor disconnect switch. If not, check the following:
• All switches between drive and motor are closed.
• All cables between drive and motor are connected and secured.

If no issue was detected and drive output was actually connected to motor, contact your supplier.
A791
Brake resistor 		 Cause: Brake resistor broken or not connected.


Solution:

1. Check that a brake resistor has been connected.
2. Check the condition of the brake resistor.
A792
Brake resistor
wiring		 Cause: Brake resistor short circuit or brake chopper control fault.

Solutions:

1. Check brake chopper and brake resistor connection.
2. Ensure brake resistor is not damaged.
A793
BR excess
temperature		 Cause: Brake resistor temperature has exceeded warning limit defined by parameter 43.12 Brake resistor warning limit.


Solution:

1. Stop drive. Let resistor cool down.
2. Check resistor overload protection function settings (parameter group 43 Brake chopper).
3. Check warning limit setting, parameter 43.12 Brake resistor warning limit.
4. Check that the resistor has been dimensioned correctly.
5. Check that braking cycle meets allowed limits.
A794
BR data		 Cause: Brake resistor data has not been given.

Solution: Check the resistor data settings (parameters 43.08…43.10).
A79B
BC short
circuit		 Cause: Short circuit in brake chopper IGBT.

Solution:

1. Replace brake chopper if external.
2. Ensure brake resistor is connected and not damaged.
A79C
BC IGBT excess
temperature		 Cause: Brake chopper IGBT temperature has exceeded internal warning limit.

Solution:

1. Let chopper cool down.
2. Check for excessive ambient temperature.
3. Check for cooling fan failure.
4. Check for obstructions in the air flow.
5 Check the dimensioning and cooling of the cabinet.
6. Check resistor overload protection function settings (parameters 43.06… 43.10).
7. Check minimum allowed resistor value for the chopper being used.
9. Check that braking cycle meets allowed limits.
10 Check that drive supply AC voltage is not excessive.
A7AC
Main IOMCU
internal error		 Cause: Calibration data is not stored in the main IOMCU. Analog signals are not working with full accuracy.

Solution:

1. This is hardware or software issue in drive.
2. Need to repair or replace drive.
A7CE
EFB comm loss		 Cause: Communication loss action Communication break in embedded fieldbus (EFB) communication.

Solution:

1. Check the status of the fieldbus master (online/offline/error etc.).
2. Check cable connections to the EIA-485 terminals 25, 26, 27 and 28 on the control unit.
3. This is a programmable warning check parameter 58.14.
A7EE
Panel loss		 Cause: Control panel or PC tool selected as active control location for drive has ceased communicating.

Solution:

1. Check PC tool or control panel connection.
2. Check control panel connector.
3. Check mounting platform if being used. Disconnect and reconnect the control panel.
4. This is a programmable warning check parameter 49.05 Communication loss action.
A8A0
AI supervision		 Cause: An analog signal is outside the limits specified for the analog input.

Solution:

1. Check signal level at the analog input.
2. Check the wiring connected to the input.
3. Check the minimum and maximum limits of the input in parameter group 12 Standard AI.
4. This is a programmable warning check parameter 12.03 AI supervision function.
A8A1
RO life
warning 		 Cause: The relay has changed states more than the recommended number of times.

Solution:

1. Change the control board or stop using the relay output.
A8A2
RO toggle
warning		 Cause: The relay output is changing states faster than recommended, eg. if a fast changing frequency signal is connected to it. The relay lifetime will be exceeded shortly.

Solution: Replace the signal connected to the relay output source with a less frequently changing signal.
A8B0
Signal supervision		 Cause: Warning generated by a signal supervision function.

Solution:
1. Check the source of the warning (parameter 32.07 Supervision 1 signal).
2. This is a programmable warning check parameter 32.06 Supervision 1 action
A8B1
Signal supervision		 Cause: Warning generated by a signal supervision function.

Soultion:

1. Check the source of the warning (parameter 32.17 Supervision 2 signal).
2. This is a programmable warning check parameter 32.16 Supervision 2 action.
A8B2
Signal supervision		 Cause: Warning generated by a signal supervision function.

Soultion:

1. Check the source of the warning (parameter 32.27 Supervision 3 signal).
2. This is a programmable warning check parameter 32.26 Supervision 3 action.
A8B3
Signal supervision		 Cause: Warning generated by a signal supervision function.

Soultion:

1. Check the source of the warning (parameter 32.37 Supervision 4 signal).
2. This is a programmable warning check parameter 32.36 Supervision 4 action.
A8B4
Signal supervision		 Cause: Warning generated by a signal supervision function.

Soultion:

1. Check the source of the warning (parameter 32.47 Supervision 5 signal).
2. This is a programmable warning check parameter 32.46 Supervision 5 action.
A8B5
Signal supervision		 Cause: Warning generated by a signal supervision function.

Soultion:

1. Check the source of the warning (parameter 32.57 Supervision 6 signal).
2. This is a programmable warning check parameter 32.56 Supervision 6 action.

A8BE
ULC overload		 Cause: Selected signal has exceeded the user overload curve.

Solution:

1. Check for any operating conditions increasing the monitored signal (forexample, the loading of the motor if the torque or current is being monitored).
2. Check the definition of the load curve (parameter group 37 User load curve 
A8BF
ULC
underload		 Cause: Selected signal has fallen below the user underload curve.

Solution:

1. Check for any operating conditions decreasing the monitored signal (forexample, loss of load if the torque or current is being monitored).
2. Check the definition of the load curve (parameter group 37 User load curve.
A8C0
ULC invalid
speed table		 Cause: User load curve: X-axis points (speed) are not valid.

Soultion:

Check that points fulfill conditions. See parameter
37.11 ULC speed table point 1.
A8C1
ULC overload
warning		 Cause: User load curve: Signal has been too long over the overload curve.

Soultion: See parameter 37.03 ULC overload actions.
A8C4
ULC underload
warning		 Cause: User load curve: Signal has been too long under the underload curve.

Soultion: See parameter 37.04 ULC underload actions.
A8C5
ULC invalid
underload table		 Cause: User load curve: Underloadcurve points are not valid.

Soultion: Check that points fulfill conditions. See parameter 37.21 ULC underload point 1.
A8C6
ULC invalid
overload table		 Cause: User load curve- Overload curve points are not valid.

Soultion: Check that points fulfill conditions. See parameter 37.31 ULC overload point 1.
A8C8
ULC invalid
frequency table		 Cause: User load curve- X-axis points (frequency) are not valid.

Soultion:

1. Check that points fulfill conditions. -500.0 Hz <37.16 <37.17 <37.18 <37.19 <37.20 < 500.0 Hz.
2. See parameter 37.16 ULC frequency table point 1.

A981
External warning 1		 Cause: Fault in external device 1.

Soultion:

1. Check the external device.
2. Check setting of parameter 31.01 External event 1 source.
3. This is a Programmable warning: check parameter - 31.01 External event 1 source 31.02 External event 1 type
A982
External warning 2		 Cause: Fault in external device 2.

Soultion:

1. Check the external device.
2. Check setting of parameter 31.03 External event 2 source.
3. This is a Programmable warning: Check parameter 31.03 External event 2 source, 31.04 External event 2 type 
A983
External warning 3		 Cause: Fault in external device 3.

Soultion:

Check the external device.
Check setting of parameter 31.05 External event 3 source.
This is a Programmable warning: check parameter 31.05 External event 3 source, 31.06 External event 3 type.
A984
External warning 4		 Cause: Fault in external device 5.

Soultion:

1. Check the external device.
2. Check setting of parameter 31.07 External event 4 source.
3. This is a Programmable warning: check parameter 31.07 External event 4 source 31.08 External event 4 type.
A985
External warning 5		 Cause: Fault in external device 5.

Solution:

Check the external device.
Check setting of parameter 31.09 External event 5 source.
This is a Programmable warning: check parameter 31.09 External event 5 source 31.10 External event 5 type.
AF88
Season
configuration
warning		 Cause: You have configured a season which starts before the previous season.

Solution:

1. Configure the seasons with increasing start dates, see parameters 34.60 Season 1 start date…34.63 Season 4 start date.
AF8C
Process PID
sleep mode		 Cause: The drive is entering sleep mode.

Solution:

1. This is a informative warning no need to take any action.
2. See section Sleep and boost functions for process PID control, and parameters 40.43…40.48. 
AF90
Autotune 		 Cause: The autotune routine has been interrupted.

Solution: The code contains an auxiliary value that specifies the reason for the abortion. For details, see section Speed controller autotune.

AFAA
Autoreset 		 Cause: A fault is about to be autoreset.

Solution:

1. This is a informative warning no need to take any action.
2. See the settings in parameter group 31 Fault functions.

AFE1
Emergency stop
(off2)		 Cause: Drive has received an emergency stop (mode selection off2) command.

Solution:

1. Check that it is safe to continue operation. Then return emergency stop push button to normal position. Restart drive.
2. If the emergency stop was unintentional, check the source selected by parameter 21.05 Emergency stop source.

AFE2
Emergency stop
(off1 or off3)		 Cause: Drive has received an emergency stop (mode selection off1 or off3) command.

Solution:

1. Check that it is safe to continue operation. Then return emergency stop push button to normal position. Restart drive.
2. If the emergency stop was unintentional, check the source selected by parameter 21.05 Emergency stop source.

AFE9
Start delay		 Cause: The start delay is active and the drive will start the motor after a predefined delay.

Solution:

1. This is a informative warning no need to take any action.
2. See parameter 21.22 Start delay.
AFED
Enable to rotate		 Cause: Signal enable to rotate has not been received within a fixed time delay of 240s.

Solution:

1. Switch enable to rotate signal on (eg. in digital inputs).
2. Check the setting of (and source selected by) parameter 20.22 Enable to rotate.
AFEE
Start
interlock 1		 Cause: Start interlock 1 is keeping the drive from starting.


Solution:

1. Check the signal source selected for parameter 20.41 Start interlock 1.
AFEF
Start
interlock 2		 Cause: Start interlock 2 is keeping the drive from starting.

Solution:

1. Check the signal source selected for parameter 20.42 Start interlock 2.
AFF0
Start
interlock 3		 Cause: Start interlock 3 is keeping the drive from starting.

Solution:

1. Check the signal source selected for parameter 20.43 Start interlock 3.
AFF1
Start
interlock 4		 Cause: Start interlock 4 is keeping the drive from starting.

Solution:

1. Check the signal source selected for parameter 20.44 Start interlock 4.
AFF2
Start interlock
forced
warning		 Cause: A forced DI is used as a source for parameter 20.40 Run permissive.

Solution:

1. If 20.40 Run permissive uses DIx as the source, check if the bit correspondingto DIx in parameter 10.03 DI force selection.
AFF3
Run
permissive
forced
warning		 Cause: One or more forced DIs is used as a source for one or more of parameters20.41 Start interlock 1 … 20.44 Start interlock 4

Solution:

1. Check all parameters 20.41 Start interlock 1 … 20.44 Start interlock 4. If any of these parameters uses DIx as the source,
2. Check if the bit corresponding to DIx in parameter 10.03 DI force selection is 1.
AFF5
Override new
start required		 Cause: The Safe torque off function was active and has been reset while in Override.

Solution:

1. A new start signal is required to start the drive again.
AFF6
Identification run		 Cause: Motor ID run will occur at next start.

Solution:

1. This is a informative warning no need to take any action.
AFFE
Override
active		 Cause: Drive is in override mode.

Solution:

1. This is an informative warnin.
B5A0
STO event		 Cause: Safe torque off function is active, ie. safety circuit signal(s) connected to connector STO is lost.

Solution:

1. Check safety circuit connections.
2. This is programmable event check parameter 31.22 STO indication run/stop. 
B5A2
Power
applied		 Cause: The drive was powered up or the control board was rebooted successfully.

Solution:

1. This is a informative event.
B5F6
ID run
done		 Cause: ID run completed.

Solution: This is a informative event.
B681
Hand mode
selected		 Cause: The drive was placed in Hand mode.

Solution:

1. This is a informative event.
2. Check the control panel to ensure that the current control location is correct.
B682
Off mode
selected		 Cause: The drive was placed in Off mode.

Solution:

1. This is a Informative event.
2. Check the control panel to ensure that the current control location is correct.
B683
Auto mode
selected		 Cause: The drive was placed in Auto mode.

Solution:

1. This is a Informative event.
2. Check the control panel to ensure that the current control location is correct.
B686
Checksum mismatch		 Cause: The calculated parameter checksum does not match any enabled reference checksum.

Solution:

1. Check that all necessary approved (reference) checksums (parameters96.71…96.72) are enabled in parameter 96.55 Checksum control word.
2. Check the parameter configuration. Using parameter 96.55 Checksum control word, enable a checksum parameter and copy the actual checksum into that parameter.
B687
Auto start
command		 Cause: The drive received a start command while in Auto mode.

Solution:

1. This is a informative event.
B688
Auto stop
command		 Cause: The drive received a stop command while in Auto mode.

Solution: This is a informative event.
B689
Modulating
started		 Cause: The drive started modulating.

Solution: This is a informative event.
B68A
Modulating
stopped		 Cause: The drive stopped modulating.

Solution: This is a informative event.
FA81
Safe torque
off 1		 Cause: Safe torque off function is active, ie. STO circuit 1 is broken.

Solution: Check safety circuit connections.
FA82
Safe torque
off 2		 Cause: Safe torque off function is active, ie. STO circuit 2 is broken.

Solution: Check safety circuit connections.
FF61
ID run		 Cause: Motor ID run was not completed successfully.

Solution:

1. Check the nominal motor values in parameter group 99 Motor data.
2. Check that no external control system is connected to the drive.
3. Cycle the power to the drive (and its control unit, if powered separately).
4. Check that no operation limits prevent the completion of the ID run. Restore parameters to default settings and try again.
5. Check that the motor shaft is not locked.
FF63
STO
diagnostics
failure		 Cause: Internal SW malfunction.

Solution: Reboot the control unit (using parameter 96.08 Control board boot) or by cycling power.
FF8E
EFB force
trip 		 Cause: A fault trip command has been received through the embedded fieldbus interface.

Solution: Check the fault information provided by the PLC.
4380
Excess
temperature
difference		 Cause: High temperature difference between the IGBTs of different phases.

Solution:

1. Check the motor cabling.
2. Check cooling of drive module(s).

How to Read ACH180 Faults via Drivetune & Software

The standard ACH180 often ships with a simplified “Icon-Based” control panel to save space. To get detailed “plain text” diagnostics in 2026, you should utilize the drive’s digital connectivity options:

  • Drivetune App (Mobile): By attaching the optional Bluetooth Control Panel (ACH-AP-W), you can pair your smartphone to the drive. The Drivetune App converts the cryptic 4-digit codes into full text descriptions with troubleshooting steps, allowing you to email logs to support teams instantly.
  • Drive Composer (PC Tool): For deep analysis, connect via USB. The “Event Logger” is essential for HVAC troubleshooting, as it allows you to see if faults (like “Input Phase Loss”) coincide with building power transfers or generator tests.
  • HVAC Specific Features: The ACH180 has built-in logic for Fireman’s Override and Damper Control. If you see faults related to “Override Active” or “Pre-Safety,” checking the status via software is safer than manual inspection.

Frequently Asked Questions (FAQ)

Q: What is the difference between a Warning and a Fault on the ACH180?

A:

  • Warning (A-Codes): The drive detects an issue (e.g., A780 “Motor Stall”) but keeps the fan/pump running to maintain air quality or pressure.
  • Fault (F-Codes): The drive stops modulation immediately to protect the motor. The red LED on the panel will be lit.

Q: How do I reset an ABB ACH180 fault?

A:

  1. Press the Stop/Reset button on the local panel.
  2. Toggle the Digital Input defined in the “Start/Stop” parameters.
  3. Cycle the main power (wait for the display to go dark).
  4. Note: In HVAC, ensure the “Auto-Reset” function (Group 31) isn’t masking a recurring problem like a loose belt or blocked filter.

Q: Why does my drive trip on “Dry Run” (D4B0)?

A: The ACH180 has a dedicated HVAC feature to detect if a pump is running dry (no load). If this trips, check your inlet water supply or check for broken belts if the drive is controlling a fan.

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