Danfoss VLT 5000 Drive Fault Codes List

Access the complete reference guide for legacy Danfoss VLT 5000 fault codes. Learn to diagnose Alarm 14 (Ground Fault), Alarm 8 (Undervoltage), and use MCT 10 with RS-485.

Danfoss VLT 5000 Fault Codes Reference Table

Fault Code and MeaningCause and Remedy
WARNING 1
Under 10 Volts (10 VOLT LOW)		Cause: The 10 Volts voltage from terminal 50 on the control card is below 10 Volts. The 10 Volts supply is overloaded.

Remedy:
  • Remove some of the load from terminal 50 (Max. 17 mA/min. 590 Ω).
WARNING/ALARM 2
Live zero fault (LIVE ZERO ERROR)		Cause: The current signal on terminal 60 is less than 50% of the value set in parameter 315 Terminal 60, min. scaling.

Remedy:
  • Check the signal on terminal 60.
  • Check parameter 315 settings.
WARNING/ALARM 3
No motor (NO MOTOR)		Cause: The motor check function (parameter 122) indicates that no motor has been connected to the output of the frequency converter.

Remedy:
  • Check motor connection.
WARNING/ALARM 4
Phase fault (MAINS PHASE LOSS)		Cause: A phase is missing on the supply side, the mains voltage imbalance is too high, or there is a fault in the input rectifier on the frequency converter.

Remedy:
  • Check the supply voltage.
  • Check supply currents to the frequency converter.
WARNING 5
Voltage warning high (DC LINK VOLTAGE HIGH)		Cause: The intermediate circuit voltage (DC) is higher than the overvoltage limit of the control system. The frequency converter is still active.

Remedy:
  • Check for deceleration regeneration issues.
  • Check supply voltage.
WARNING 6
Voltage warning low (DC LINK VOLTAGE LOW)		Cause: The intermediate circuit voltage (DC) is below the undervoltage limit of the control system. The frequency converter is still active.

Remedy:
  • Check supply voltage quality and level.
WARNING/ALARM 7
Overvoltage (DC LINK OVERVOLT)		Cause: The intermediate circuit voltage (DC) exceeds the inverter overvoltage limit.

Remedy:
  • Connect a brake resistor (if the unit has an integral brake chopper).
  • Extend the time chosen in parameter 410.
  • Activate Brake function/overvoltage control in parameter 400.
WARNING/ALARM 8
Undervoltage (DC LINK UNDERVOLT)		Cause: The intermediate circuit voltage (DC) drops below the inverter lower voltage limit.

Remedy:
  • Check if 24 V power supply is connected.
  • Check whether the supply voltage matches the frequency converter technical data.
WARNING/ALARM 9
Inverter overload (INVERTER TIME)		Cause: The electronic, thermal inverter protection reports that the frequency converter is about to cut out because of an overload (too high current for too long).

Remedy:
  • Reduce load or check application sizing.
  • Wait for the counter to drop below 90% to reset.
WARNING/ALARM 10
Motor overtemperature (MOTOR TIME)		Cause: According to the electronic thermal protection (ETR), the motor is too hot. The counter has reached 100%.

Remedy:
  • Check that motor parameters 102-106 have been set correctly.
  • Check for motor overloading.
WARNING/ALARM 11
Motor thermistor (MOTOR THERMISTOR)		Cause: The thermistor or the thermistor connection has been disconnected.

Remedy:
  • Check that the thermistor has been correctly connected between terminal 53 or 54 (analogue voltage input) and terminal 50 (+ 10 Volts supply).
WARNING/ALARM 12
Torque limit (TORQUE LIMIT)		Cause: The torque is higher than the value in parameter 221 (in motor operation) or the torque is higher than the value in parameter 222 (in regenerative operation).

Remedy:
  • Check load conditions.
  • Adjust torque limit parameters if safe for the application.
WARNING/ALARM 13
Overcurrent (OVERCURRENT)		Cause: The inverter peak current limit (approx. 200% of the rated current) has been exceeded.

Remedy:
  • Turn off the frequency converter and check whether the motor shaft can be turned.
  • Check whether the motor size matches the frequency converter.
  • Reset externally if extended mechanical brake control is selected.
ALARM: 14
Earth fault (Earth fault)		Cause: There is a discharge from the output phases to earth, either in the cable between the frequency converter and the motor or in the motor itself.

Remedy:
  • Turn off the frequency converter.
  • Remove the earth fault in the cable or motor.
ALARM: 15
Switch mode fault (SWITCH MODE FAULT)		Cause: Fault in the switch mode power supply (internal ± 15 V supply).

Remedy:
  • Contact your Danfoss supplier.
ALARM: 16
Short-circuiting (CURR.SHORT CIRCUIT)		Cause: There is short-circuiting on the motor terminals or in the motor itself.

Remedy:
  • Turn off the frequency converter.
  • Remove the short-circuit.
WARNING/ALARM 17
Standard bus timeout (STD BUS TIMEOUT)		Cause: There is no communication to the frequency converter. Only active if parameter 514 is not OFF.

Remedy:
  • Check bus communication cabling.
  • Parameter 513 Bus time interval could possibly be increased.
WARNING/ALARM 18
HPFB bus timeout (HPFB BUS TIMEOUT)		Cause: There is no communication with the frequency converter. Only active if parameter 804 is not OFF.

Remedy:
  • Check bus communication cabling.
  • Parameter 803 Bus time interval could possibly be increased.
WARNING 19
Fault in the EEprom on the power card (EE ERROR POWER CARD)		Cause: There is a fault on the power card EEPROM. The frequency converter will likely fail at the next power-up.

Remedy:
  • Contact your Danfoss supplier.
WARNING 20
Fault in the EEprom on the control card (EE ERROR CTRL CARD)		Cause: There is a fault in the EEPROM on the control card. The frequency converter will likely fail at the next power-up.

Remedy:
  • Contact your Danfoss supplier.
ALARM 21
Auto-optimisation OK (AUTO MOTOR ADAPT OK)		Cause: The automatic motor tuning is OK and the frequency converter is now ready for operation.

Remedy:
  • No action required.
ALARM 22
Auto-optimisation not OK (AUTO MOT ADAPT FAIL)		Cause: A fault has been found during automatic motor adaptation (AMA). The figure in brackets [] indicates the specific fault code:
[0]: CHECK P.103,105
[1]: LOW P.105
[2]: ASYMMETRICAL IMPEDANCE
[3]: MOTOR TOO BIG
[4]: MOTOR TOO SMALL
[5]: TIME OUT
[6]: INTERRUPTED BY USER
[7]: INTERNAL FAULT
[8]: LIMIT VALUE FAULT
[9]: MOTOR ROTATES

Remedy:
  • Note: AMA can only be carried out if there are no alarms during tuning.
  • Refer to the "Automatic motor adaptation, AMA" section in the manual for specific code troubleshooting.
WARNING/ALARM 23
Fault during brake test (BRAKE TEST FAILED)		Cause: The brake test (run after power-up) found a fault. Possible reasons:
- No brake resistor connected.
- Fault in the connections.
- Defective brake resistor or defective brake transistor.

Remedy:
  • Check brake resistor connections.
  • Replace defective components.
WARNING 25
Brake resistor fault (BRAKE RESISTOR FAULT)		Cause: The brake resistor is monitored during operation and if it short-circuits, the brake function is disconnected.

Remedy:
  • Turn off the frequency converter.
  • Replace the brake resistor.
ALARM/WARNING 26
Brake resistor power 100% (BRAKE PWR WARN 100%)		Cause: The power transmitted to the brake resistor (calculated as a percentage mean over 120s) is higher than 100%.

Remedy:
  • Reduce braking cycle or load.
  • If Trip [2] is selected in parameter 403, the converter will cut out.
WARNING 27
Brake transistor fault (BRAKE IGBT FAULT)		Cause: The brake transistor is short-circuited. Substantial power will be transmitted to the brake resistor, even if inactive.

Remedy:
  • Turn off the frequency converter.
  • Remove the brake resistor.
ALARM: 29
Heat sink temperature too high
(HEAT SINK OVER TEMP.)		Cause: The cut-out temperature of the heat-sink has been exceeded (90°C for IP 00/20, 80°C for IP 54). The fault cannot be reset until the temperature is below 60°C.
The fault could be:
  • Ambient temperature too high.
  • Too long motor cable.
  • Too high switching frequency.
ALARM: 30
Motor phase U missing
(MISSING MOT.PHASE U)		Cause: Motor phase U between frequency converter and motor is missing.

Remedy:
  • Turn off the frequency converter.
  • Check motor phase U.
ALARM: 31
Motor phase V missing
(MISSING MOT.PHASE V)		Cause: Motor phase V between frequency converter and motor is missing.

Remedy:
  • Turn off the frequency converter.
  • Check motor phase V.
ALARM: 32
Motor phase W missing
(MISSING MOT.PHASE W)		Cause: Motor phase W between frequency converter and motor is missing.

Remedy:
  • Turn off the frequency converter.
  • Check motor phase W.
ALARM: 33
Quick discharge not OK
(QUICK DISCHARGE NOT OK)		Remedy:
  • Check whether a 24 Volt external DC supply has been connected.
  • Check that an external brake/discharge resistor has been fitted.
WARNING/ALARM: 34
Fieldbus communication fault
(FIELDBUS COMMUNICATION FAULT)		Cause: The fieldbus on the communication option card is not working.
WARNING: 35
Out of frequency range
(OUT OF FREQUENCY RANGE)		Cause: This warning is active if the output frequency has reached its Output frequency low limit (parameter 201) or Output frequency high limit (parameter 202).
Note: If in Process control, closed loop, bit 008000 will be active in extended status word, but there will be no warning in the display.
WARNING/ALARM: 36
Mains failure
(MAINS FAILURE)		Cause: Supply voltage to the frequency converter is lost and parameter 407 is set to a value other than OFF.

Remedy:
  • Check the fuses to the frequency converter.
ALARM: 37
Inverter fault (Inverter fault)		Cause: IGBT or the power card is defective.
Remedy: Contact your Danfoss supplier.

Auto-optimisation warnings:
AMA has stopped, likely due to wrong parameters or motor size mismatch.
Remedy:
  • Press [CHANGE DATA] and choose 'Continue' + [OK] or 'Stop' + [OK].
  • If parameters need changing, select 'Stop' and start AMA all over.
WARNING: 39
CHECK P.104, 106		Cause: The setting of parameter 102, 104 or 106 is probably wrong.

Remedy:
  • Check the setting.
  • Choose 'Continue' or 'Stop'.
WARNING: 40
CHECK P.103, 105		Cause: The setting of parameter 102, 103 or 105 is probably wrong.

Remedy:
  • Check the setting.
  • Choose 'Continue' or 'Stop'.
WARNING: 41
MOTOR TOO BIG		Cause: The motor used is probably too big for AMA to be carried out. The setting in parameter 102 may not match the motor.

Remedy:
  • Check the motor.
  • Choose 'Continue' or 'Stop'.
WARNING: 42
MOTOR TOO SMALL		Cause: The motor used is probably too small for AMA to be carried out. The setting in parameter 102 may not match the motor.

Remedy:
  • Check the motor.
  • Choose 'Continue' or 'Stop'.
ALARM: 43
Brake fault (BRAKE FAULT)		Cause: A fault has arisen on the brake. See specific sub-faults below:

[0] Brake check failed: Brake disconnected.
  • Check whether brake is connected correctly.

[1] Brake resistor short-circuited:
  • Replace the brake resistor.

[2] Brake IGBT short-circuited: Unit is unable to stop the brake; resistor is constantly energized.
WARNING/ALARM: 44
Encoder loss
(ENCODER FAULT)		Cause: The encoder signal is interrupted from terminal 32 or 33.

Remedy:
  • Check the connections.
WARNING/ALARM: 57
Overcurrent
(OVERCURRENT)		Cause: As warning/alarm 13, but in this case the warning/alarm occurs together with a quick stop.
ALARM: 60
Safety stop
(EXTERNAL FAULT)		Cause: Terminal 27 (parameter 304 Digital Inputs) has been programmed for a safety interlock [3] and is a logic '0'.

 

How to Read VLT 5000 Faults via LCP & MCT 10

Troubleshooting a VLT 5000 in 2026 requires bridging the gap between old hardware and new software. Here is how to access diagnostics:

  • MCT 10 (Motion Control Tool): Even though the VLT 5000 is obsolete, the modern MCT 10 software still supports it. However, you cannot use USB.
    • Connection: You must use an RS-485 to USB converter connected to the 9-pin D-Sub port (or terminals 68/69) on the drive.
    • Diagnostics: Once connected, you can view the Alarm Log (Parameter 600-630 range) to see the last 10 faults with the “Value at Trip” data.
  • Local Control Panel (LCP): The VLT 5000 display is alphanumeric.
    • Alarm (AL): The drive trips and the red LED flashes.
    • Warning (W): The drive runs, but the yellow LED is on.
    • Extended Status: Press the [Display / Status] button to toggle between frequency, current, and alarm codes.
  • Capacitor Aging: If you are pulling a VLT 5000 spare off the shelf that has sat for >3 years, do not apply full power immediately. The DC Bus capacitors must be reformed (voltage increased gradually) to prevent them from venting/exploding.

Frequently Asked Questions (FAQ)

Q: What is the difference between Warning (W) and Alarm (AL)?

A:

  • Warning: The drive detects a limit (e.g., Warning 10 “Motor Overterm”) but keeps modulating. If the condition clears, the warning disappears.
  • Alarm: A latching fault (e.g., Alarm 16 “Short Circuit”). The drive stops immediately and requires a manual reset.

Q: How do I reset a Danfoss VLT 5000 fault?

A:

  1. Press the Reset button on the LCP keypad.
  2. Toggle Terminal 27 (This is the standard “Coast/Reset” input on the VLT 5000).
  3. Cycle the mains power (wait for the DC bus to discharge completely).

Q: What causes “Alarm 14” (Earth Fault)?

A: This is very common on aging installations.

  • It indicates current is leaking from the motor output to the ground.
  • Test: Disconnect the motor cables from the drive and run the drive empty. If it doesn’t trip, the drive is fine—check your motor insulation (Megger test) and look for water in the conduit.

Q: Can I replace a VLT 5000 with an FC 302?

A: Yes, the Automation Drive FC 302 is the direct successor. However, the terminal numbering and parameter structure are different. You should use the “VLT 5000 to FC 300 Conversion Tool” built into MCT 10 to migrate your parameter set.

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