- Networks
- Smart locks
Error 4A
Nuki Error 4A smart lock: main motor unable to rotate
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
High
Quick answer
For Error 4A on a Nuki Smart Lock Go or 4th Generation lock, check firmware and full battery charge, then calibrate while beside the door. Follow the further Nuki App instructions if the motor still cannot turn.
Safety first
Stop and check this first
- Check the door locally after calibration for 4A: Nuki warns that lost position can cause the key to turn in the opposite direction when correcting the lock state.
Safe checks you can perform
- Match the 4A message and review Smart Lock firmware
- Establish full battery charge before diagnosing 4A
- Run the local calibration specified for Error 4A
Leave these tasks to a qualified professional
- Do not attempt this professional task: Check the 4A lock’s firmware and power prerequisites
- Do not attempt this professional task: Verify local calibration and follow Nuki’s further 4A guidance
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Check the 4A lock’s firmware and power prerequisites
What they doThe technician matches the model to Nuki’s 4A page, reviews the firmware and confirms full battery charge before drawing conclusions about the main motor.
They must show youthe checked firmware, charge status and motor response when the 4A check is repeated.
In writingGo or 4th Generation model, completed checks and whether Error 4A remains.
Verify local calibration and follow Nuki’s further 4A guidance
What they doThe professional assists with calibration within Bluetooth range and follows the further Nuki App instructions if Error 4A persists afterward.
They must show youthe completed or failed local calibration and the assistance instruction displayed for 4A.
In writingcalibration outcome, observed door state and the next official instruction for the 4A motor issue.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Match the 4A message and review Smart Lock firmware
- Who:
- you, with authorized app access to the affected Smart Lock Go or 4th Generation unit.
- How:
- confirm that the recorded message is 4A and check whether the latest Smart Lock firmware is installed; follow the official update procedure offered by Nuki.
- Result that matters:
- match the reported fault and apply the firmware step documented for 4A.
- If updating clears the 4A message:
- retain the outcome of the firmware change.
- If the main motor still cannot turn after updating:
- check the available battery charge next.
- Evidence to keep:
- affected Nuki model and the 4A status after the firmware update.
Evidence: Troubleshooting a 4A error
Establish full battery charge before diagnosing 4A
- Who:
- you, checking the power status of the lock displaying Error 4A.
- How:
- confirm whether its batteries are fully charged; if battery work is needed and you have no applicable owner procedure, arrange it through Nuki support or a technician.
- Result that matters:
- meet Nuki’s power prerequisite before treating 4A as evidence of a motor defect.
- If charge is complete and 4A clears:
- record how the Smart Lock responded.
- If 4A remains with full charge available:
- proceed to the manufacturer’s local calibration step.
- Evidence to keep:
- confirmed charge state and whether the 4A message remained visible.
Evidence: Troubleshooting a 4A error
Run the local calibration specified for Error 4A
- Who:
- you, using authorized Nuki access within Bluetooth range of the affected lock.
- How:
- select the Smart Lock in the Nuki App, enter its settings and choose Features & Configuration > General > Calibrate Smart Lock; follow the prompts and check the outcome on site.
- Result that matters:
- relearn lock positions through the calibration step in Nuki’s 4A guidance.
- If calibration finishes and the motor responds without 4A:
- verify the door state in person.
- If the Nuki App still reports 4A:
- follow its further assistance instructions.
- Evidence to keep:
- calibration outcome and the app wording after the attempt to resolve 4A.
Evidence: Troubleshooting a 4A error · How to calibrate your Smart Lock
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Networks
- Brand
- Nuki
- Product type
- Smart locks
Known code variants
- 4A
- Error 4A en Smart Lock
- Main motor cannot turn
- Motor principal no se activa
- Smart Lock error 4A
What it means
Nuki’s page “Troubleshooting a 4A error” covers Smart Lock Go and Smart Lock (4th Generation), defining 4A as an inability to turn the main motor. Its troubleshooting sequence includes current firmware, fully charged batteries and calibration. Applicability must be checked separately for other Nuki model families, which may need different guidance. Error 4A by itself does not establish that the motor or any other component has failed.
Warnings and stop conditions
- Mediumsource verified
Check the door locally after calibration for 4A: Nuki warns that lost position can cause the key to turn in the opposite direction when correcting the lock state.
Evidence: How to calibrate your Smart Lock
Symptoms and causes
Probable causes · in order
- Insufficient charge for motor operationPossible
The 4A guidance calls for fully charged batteries so that the Smart Lock has enough power to turn its main motor.
Evidence: Troubleshooting a 4A error
- Outstanding motor maintenance firmwarePossible
The latest firmware includes ongoing motor maintenance, which Nuki lists as part of the troubleshooting procedure for 4A.
Evidence: Troubleshooting a 4A error
Virtual technician
Does Error 4A still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
Nuki Home Solutions · 2026 · official_doc
- 2
Nuki Home Solutions · 2026 · official_doc
- 3
How to calibrate your Smart Lock
Nuki Home Solutions · 2026 · official_doc
- 4
Nuki Home Solutions · 2026 · official_doc
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