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Fault code index · Powerwall 2 · Powerwall 3 · Gateway

Tesla Powerwall Fault & Alert Guide

Every Tesla Powerwall app alert, LED indicator state, and Gateway error — what each notification means, the most likely cause, and what to do next. Covers Powerwall 2, Powerwall 3, Powerwall+, Backup Gateway 2, and Backup Switch.

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Alerts shown in the Tesla app LED states + Gateway status Powerwall 2 · Powerwall 3 · PW+

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LED indicators App alerts Battery faults Gateway & comms Grid & backup PW3 solar
How Tesla Powerwall alerts work

Tesla Powerwall does not use numbered fault codes like traditional inverters. Instead, it communicates through two channels:

APP Plain-English alerts in the Tesla app — e.g. "Powerwall Disabled", "Breaker Open", "Low Energy Lockout"
LED LED indicators on the Powerwall unit — colour and pattern show operating state, charging, or fault
GW Gateway status — the hub connecting Powerwall to your network and the Tesla cloud

Most alerts resolve with a power cycle or Gateway reset. "Service Required" alerts typically need a professional visit or Tesla warranty claim.

LED indicator states

The LED on the front of the Powerwall shows operating status through colour and pattern. Powerwall 2 has a single LED strip on the right side. Powerwall 3 has a logo LED plus a separate status LED. Check the LED first when investigating a fault — it tells you the unit's state before you open the app.

Solid green Normal · standby
The Powerwall is connected, communicating with the Gateway, and in standby — ready to charge or discharge as needed. This is the normal idle state when the battery is not actively cycling. No action required.
Pulsing green Normal · active
The Powerwall is actively charging or discharging. The pulsing rhythm indicates energy flow. This is normal operating behaviour — the battery is either storing solar energy, discharging to power your home, or participating in a time-of-use schedule. No action required.
Solid white Normal · PW3 operating
On Powerwall 3, a solid white logo LED means the system is operating normally. The separate status LED may show additional information — light blue/aqua means the unit is ready for commissioning, and other colours indicate different setup stages. If the logo LED is solid white, the system is healthy.
Flashing green Warning · no Gateway comms
The Powerwall is powered on and enabled but cannot communicate with the Gateway. The battery itself is functional but the monitoring link is down — the Tesla app will show no live data. Check your internet connection, restart the router, and verify the Gateway has power. If the Gateway is accessible, press the reset button. On a Backup Gateway 2 this is behind a small cover on the front panel. If flashing green persists after a Gateway reset, the communication hardware may be faulty.
Flashing red ⚠ Fault detected or firmware updating
A flashing red LED means either an internal fault has been detected or a firmware update is in progress. During a firmware update, the red flash is expected and will stop once the update completes — do not power cycle during an update. If the red flash persists for more than an hour, or the Tesla app shows "Powerwall Disabled" or "Service Required", an internal fault has occurred. Turn off the Powerwall enable switch and contact your installer or Tesla support.
Blinking / no data transfer Warning · app offline
The LED is blinking in a pattern that indicates no data is being transferred to the Tesla app. The power flow screen in the app may be greyed out or blank. Check that the Gateway has an active internet connection — Wi-Fi, Ethernet, or cellular. If the Gateway itself has lost power, the LED on the Gateway will be off. Restart the Gateway or check the breaker supplying it.
LED off No power · breaker open
The Powerwall has no power. Check the circuit breaker connecting the Powerwall to your electrical system — if it has tripped or been turned off, the LED will be completely dark. Also check the enable switch on the side of the Powerwall unit. If the breaker is on and the enable switch is on but the LED is still off, the unit may have an internal power supply fault and needs professional inspection.
Tesla app alerts

The Tesla app delivers push notifications and in-app alerts when your Powerwall changes state or detects an issue. You need an active internet connection on both your phone and the Gateway to receive these. Some alerts are informational (e.g. going off-grid during a power cut), while others require action.

Breaker Open Alert · electrical
The circuit breaker connecting the Powerwall to your home's electrical system is in the off position. The Powerwall cannot charge, discharge, or provide backup while the breaker is open. Locate the breaker in your consumer unit that feeds the Powerwall circuit and switch it back on. If the breaker trips again immediately, there may be a wiring fault on the Powerwall circuit that needs an electrician.
Side Switch Off Alert · manual
The enable switch on the side of the Powerwall unit has been turned off. The Powerwall will not power your home. On Powerwall+ and Powerwall 3, solar generation will also stop because the inverter is integrated. On Powerwall 2, solar may continue generating through your separate inverter. Check the switch on the right-hand side of the unit and flip it to the on position.
Powerwall Disabled — Service Required ⚠ Internal fault — contact installer
An internal fault has been detected and the Powerwall has shut itself down. This is one of the most serious alerts. Common causes include an internal cell failure, a DC stage fault in the power conversion hardware, or a ground fault detected during the insulation self-test. Turn off the enable switch and contact your installer or Tesla support. This typically requires a site visit and may result in a warranty replacement — a power cycle will not fix it.
Low Energy Lockout ⚠ Battery locked — replacement needed
The Powerwall has been locked out due to critically low energy and cannot recover to a chargeable state. The internal cells have discharged below the minimum recoverable threshold. This is a hardware-level lockout — the unit cannot be reset or charged back to life. Contact your installer or Tesla support to arrange a warranty replacement. This fault has affected some Powerwall 2 units and was the subject of a recall programme.
Powerwall Low Energy Alert · informational
The Powerwall charge level is low. If you are off-grid during a power cut, reduce household loads to extend your backup duration. In normal grid-connected operation, this alert means the battery has discharged to near the backup reserve threshold and will stop discharging to preserve backup capacity. The system will recharge from solar or the grid depending on your mode settings. No action needed unless you are in a power cut.
Powerwall Very Low Energy Alert · urgent
The Powerwall is critically low on energy with very limited backup time remaining. Immediately reduce your home's power consumption — switch off non-essential appliances, heating, and high-draw devices. If the grid is still available, the system will recharge. If you are off-grid during a power cut, prioritise only essential loads like lights and the fridge to extend the remaining backup as long as possible.
Powerwall Overloaded Alert · load management
The load on the backed-up circuit exceeds what the Powerwall can deliver. Each Powerwall unit supports up to 5kW continuous output — if your household demand exceeds this during a power cut, the system overloads and disconnects. You may hear audible clicking as it retries. Reduce the load by switching off high-draw appliances like kettles, ovens, and immersion heaters. The Powerwall will automatically retry within two minutes once the load drops. In multi-Powerwall systems, the combined output is higher but the total load must still stay within the aggregate rating.
Calibrating Alert · maintenance
The Powerwall is performing a routine battery calibration. During calibration, the system may charge and discharge the battery through a full cycle to recalibrate the state-of-charge reading. This can take up to 24 hours and is normal maintenance behaviour. The SOC percentage in the app may appear inaccurate during this period. No action required — the system will return to normal operation after calibration completes.
Storm Watch Alert · informational
A severe weather event has been forecast for your area and the Powerwall is charging to maximum capacity to prepare for a potential power cut. Storm Watch temporarily overrides your normal operating mode and prioritises backup readiness. Once the storm warning passes, the system returns to your previous settings. This is an automatic feature that can be enabled or disabled in the Tesla app under Powerwall settings.
Battery & thermal faults

Battery faults relate to the internal cells, temperature management, and power conversion hardware inside the Powerwall unit. Tesla's BMS monitors cell voltages, temperatures, and insulation resistance continuously. Most battery faults require professional attention — the Powerwall is a sealed unit and not user-serviceable.

Internal Fault / Battery Fault ⚠ Sealed unit — professional service required
The Powerwall's internal diagnostics have detected a fault within the battery pack or power electronics. This could be a cell failure, a manufacturing defect that has developed over time, or degradation. The Tesla app may show "Internal Fault Detected" or "Battery Fault". Turn off the enable switch on the side of the unit. The Powerwall is a sealed, non-serviceable unit — do not attempt to open it. Contact your installer to initiate a warranty claim with Tesla.
Battery Over-temperature Thermal · environment
The internal battery temperature has exceeded the safe operating limit. The Powerwall has an integrated liquid cooling system, but in extreme ambient heat or if the cooling circuit fails, the cells can overheat. Check that the unit is not in direct sunlight and has adequate clearance for airflow. The Powerwall's operating range is -20°C to 50°C. If the installation location routinely exceeds this, the unit may need relocating. The system will resume once the temperature drops.
Battery Under-temperature Thermal · cold weather
The battery temperature is below the minimum for safe charging. Powerwall has a built-in heater that activates in cold conditions, but in extreme cold the heater may not raise the temperature fast enough. The system will wait until the cells reach a safe temperature before resuming charge. Discharge may continue at a reduced rate in cold conditions. If the unit is installed outdoors or in an unheated outbuilding in the UK, sub-zero winter nights can trigger this regularly.
DC Stage Fault ⚠ Power conversion failure
The DC-to-AC power conversion stage inside the Powerwall has failed. This is the inverter circuitry that converts stored DC energy into usable AC power. A DC stage fault means the Powerwall cannot charge or discharge. This is a hardware failure that requires professional service — typically a warranty replacement of the unit. Turn off the enable switch and contact your installer.
Isolation Self-Test Failure Safety · insulation
The Powerwall performs periodic insulation resistance self-tests to verify there is no earth leakage path. A failure means the measured resistance is below the safety threshold. This can be caused by moisture ingress (rare on sealed units), internal wiring degradation, or a genuine insulation fault. The system will disable itself until the test passes. If it does not resolve within 24 hours, contact your installer — the unit may need inspection or replacement.
Powerwall Balancing Multi-unit · normal
In multi-Powerwall installations, the system is balancing the charge level between units. This is normal behaviour that occurs automatically when the state of charge differs significantly between Powerwall units. Balancing typically takes up to six hours and completes without intervention. During balancing, the system may temporarily reduce its available capacity. No action required.
Gateway & communication faults

The Backup Gateway 2 (or Backup Switch on Powerwall 3) is the brain of the system — it manages grid switching, energy monitoring, and cloud connectivity. If the Gateway goes offline, you lose monitoring and some control features, but the Powerwall typically continues operating locally.

Gateway Offline Communication · network
The Gateway has lost its internet connection. The Tesla app shows a greyed-out or blank power flow screen, and the Gateway may be making a beeping sound. Check that your router is working and the internet connection is active. Verify the Ethernet cable between the Gateway and router is firmly plugged in at both ends (if using wired connection). If connected via Wi-Fi, check the Gateway has not lost the Wi-Fi password after a router change. Press the reset button on the Backup Gateway 2 to restart the network connection.
Communication Error / No Data Communication · PW to Gateway
The Powerwall cannot communicate with the Gateway or the Tesla cloud. The LED on the Powerwall will be flashing green. The system may still charge and discharge locally, but you will not see live data in the app. Restart the Gateway by pressing the reset button or by turning off the Gateway breaker for 30 seconds. If the Gateway Wi-Fi network name or password has changed since installation, you may need to reconnect the Gateway via the Tesla app's Wi-Fi settings.
Gateway Beeping Communication · offline
The Gateway is audibly beeping, indicating it has lost connectivity. This is a deliberate audio alert to tell you the system is offline. Check the internet connection and Gateway power supply. If the Gateway has power but continues beeping after verifying the internet connection, try a full power cycle — turn off the Gateway breaker, wait 30 seconds, then turn it back on. Persistent beeping after a power cycle may indicate a hardware fault in the Gateway's communication module.
Firmware Update in Progress System · update
Tesla pushes firmware updates automatically over the internet. During an update, the Powerwall LED may flash red and the system may be temporarily unavailable. Do not turn off the Powerwall or Gateway during a firmware update — interrupting the process can leave the system in a partially updated state that requires professional recovery. Updates typically complete within 30 minutes. If the update appears stuck for more than two hours, contact Tesla support.
Firmware Update Failed System · software
A firmware update did not complete successfully. The system may repeatedly go offline for brief periods while retrying the update. Ensure the Gateway has a strong, stable internet connection — updates can fail over weak Wi-Fi. If using Wi-Fi, consider connecting the Gateway via Ethernet for the duration of the update. If the update continues to fail after ensuring good connectivity, contact Tesla support — they can push the update remotely or schedule a service visit.
Grid & backup faults

Grid and backup alerts relate to how the Powerwall interacts with the mains supply and provides emergency backup power during outages. The Backup Gateway continuously monitors grid voltage and frequency and will island your home (disconnect from the grid) if conditions fall outside safe parameters.

Going Off-Grid / Island Detected Grid · power cut
The Powerwall has detected a grid outage or grid voltage/frequency outside safe limits and has disconnected your home from the mains. Your home is now running entirely on Powerwall battery and solar (if available). This is normal backup behaviour. The Powerwall may discharge below your set backup reserve during an extended outage. Reduce household loads to extend backup duration. The system will automatically reconnect to the grid when it detects stable power has returned.
Grid Out of Compliance Grid · voltage or frequency
The grid voltage or frequency is outside the Powerwall's compliance window but has not fully dropped out. The system may hesitate to island or may island briefly and reconnect. If you notice the Powerwall did not activate during a power cut, "grid out of compliance" conditions just before the outage may have prevented the transfer. This is a known edge case — the system needs a clean transition. If your grid supply is consistently unstable, contact your DNO to report the issue.
Backup Failed / No Backup During Outage Backup · did not activate
The grid went down but the Powerwall did not provide backup power. Possible causes include the Powerwall having insufficient charge (below the backup reserve), the Gateway transfer switch failing to island the home, or a breaker being open on the backup circuit. Check that the Powerwall was charged above the backup reserve threshold at the time of the outage. Verify the Gateway breaker and Powerwall breaker are both on. If the system was charged and breakers were on but backup still failed, the Gateway transfer switch may need investigation.
Grid Reconnected Grid · informational
The grid supply has returned and the Powerwall has reconnected your home to the mains. The system will resume its normal operating mode — self-powered, time-based control, or whatever mode you had selected. The Powerwall will begin recharging from solar or grid depending on settings. No action required. This notification confirms the power cut is over and your system is back to normal.
Powerwall 3 solar-specific faults

Powerwall 3 has an integrated solar inverter, so it has additional fault types related to PV strings that Powerwall 2 does not have. These faults only appear on Powerwall 3 and Powerwall+ systems where solar panels connect directly to the unit.

Arc Fault Detected ⚠ DC arc — safety shutdown
The Powerwall 3's arc fault circuit interrupter (AFCI) has detected a potential DC arc on a solar string. This is a fire safety mechanism. The system shuts down the affected string. Inspect the DC wiring for damaged cables, loose MC4 connectors, burn marks, or poor junction box connections. If five arc fault alerts occur within 24 hours, the system enters Arc Fault Lockout — a full inspection of the DC wiring must be performed before the system can be re-enabled. Do not ignore arc faults — they indicate a genuine fire risk.
Arc Fault Lockout ⚠ Repeated arcs — system locked
Five or more arc fault alerts have occurred within 24 hours. The system has entered lockout mode and will not restart until the DC wiring has been professionally inspected and the issue remediated. A qualified electrician or solar engineer must physically inspect every MC4 connection, cable run, isolator, and junction box on the affected string. After repair, the lockout must be cleared through the commissioning tool. This is not a reset-and-hope situation — the underlying wiring fault must be found and fixed.
PV Input Overvoltage Solar · string voltage
The open-circuit voltage on a PV string connected to the Powerwall 3 exceeds the maximum DC input rating. Too many panels are connected in series on that string. Measure the string Voc with a multimeter — on cold mornings, voltage rises significantly. If the measured voltage exceeds the Powerwall 3's rated maximum, the string must be reconfigured with fewer panels in series. Do not continue operating with an over-voltage string — it can damage the internal inverter hardware.
PV Ground Fault Solar · insulation
A ground fault has been detected on the PV array connected to the Powerwall 3. The insulation resistance between the solar string and earth is below the safety threshold. Check DC cables for physical damage, inspect MC4 connectors for moisture ingress, and examine the cable runs for anything that could compromise insulation. If the fault only appears in wet weather, a connector joint or cable entry point is the likely culprit. Disconnect strings individually to isolate which one has the fault.
Alert not listed here?

Tesla regularly adds new alerts through firmware updates. If you see a notification in the Tesla app that is not covered above, share the exact alert text and your Powerwall model (2, 3, or +) and we will identify it. Screenshots from the app are especially helpful for diagnosing unusual alerts.

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Related Powerwall guides
Hub · support · diagnostics
Tesla Powerwall support hub

All Powerwall problem guides, setup help, and diagnostic resources in one place.
Backup · EPS · power cut
No backup during power cut

Why your battery did not kick in during an outage — transfer switch, SOC reserve, and Gateway checks.
App · Wi-Fi · Gateway · offline
Monitoring offline

Tesla app not updating, Gateway offline, or power flow screen greyed out — connectivity diagnosis.

Tesla Powerwall fault questions

Tesla Powerwall does not display traditional numbered fault codes. Instead, it uses two methods: the Tesla app shows plain-English alert messages like "Powerwall Disabled" or "Breaker Open", and the LED indicators on the unit show status through colour and pattern. Solid green = standby, pulsing green = active, flashing green = no Gateway communication, flashing red = fault or firmware update. Check both the app notifications and the LED when troubleshooting.

"Powerwall Disabled — Service Required" means an internal fault has been detected that prevents the unit from operating. Common causes include cell failure, a DC stage fault, or a ground fault during insulation self-testing. Turn off the enable switch on the side of the unit and contact your installer or Tesla support. This typically requires a site visit and may result in a warranty replacement — a power cycle will not fix it.

Flashing green means the Powerwall is enabled but cannot communicate with the Gateway. Check your internet connection, restart the router, and verify the Gateway has power. Try pressing the reset button on the Backup Gateway 2 (behind the small cover on the front). If flashing green persists after a Gateway reset and the internet is confirmed working, the communication link between the two devices may have a hardware fault that needs professional investigation.

STS offers remote diagnostic assessments from £75. Powerwall systems log detailed data including charge cycles, temperature history, and alert logs. We review your Tesla app data and system configuration remotely to identify the root cause and advise whether you need a Tesla warranty claim, a Gateway reset, an electrical check, or a site visit. We are independent from Tesla and provide an unbiased assessment.

Powerwall 2 is an AC-coupled battery that pairs with a separate solar inverter. Powerwall 3 is a hybrid unit with a built-in solar inverter — it connects directly to PV panels as well as the battery. Powerwall 2 uses a Backup Gateway 2 for grid switching. Powerwall 3 can use either a Backup Gateway 2 or the newer Backup Switch. Both show alerts through the Tesla app, but Powerwall 3 has additional fault types related to its integrated solar inverter — including arc fault detection and PV string monitoring.

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