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High-voltage battery overheating
BYD ATTO 3 high-voltage battery overheating light: stop
Risk level
Critical
Stop using the equipment and contact a professional.
Urgency
Immediate
Quick answer
On the BYD ATTO 3, the high-voltage battery overheating warning light means the battery temperature is too high and the vehicle must be stopped to cool down. If it flashes, BYD recommends stopping immediately in a safe place and leaving the vehicle as soon as possible.
Safety first
What to do now
- Steady or flashing
Who: you, driving. How: watch whether the light is steady or flashing. Result that matters: whether it flashes. If it flashes: stop immediately in a safe place and leave the vehicle as soon as possible; move away and call assistance. If it is steady: stop somewhere safe and let the battery cool before continuing. Evidence to keep: photo or video of the light if you can take it safely.
- Driving conditions beforehand
Who: you, once stopped. How: consider whether you came from a long climb in heat, stop-and-go traffic or a long drive without a break. Result that matters: whether it matches the conditions BYD lists. If it matches: let it cool; if the light returns in normal conditions, book an inspection. If it does not match: treat it as a possible fault and contact a BYD authorized service provider. Evidence to keep: note of outside temperature, route and driving time.
- Battery fault light at the same time
Who: you. How: check whether the high-voltage battery fault warning light is also on. Result that matters: whether there is a fault besides temperature. If it is on: BYD recommends inspection by an authorized service provider as soon as possible; do not resume driving without asking them. If it is off and the temperature light goes out once cool: carry on carefully and note the episode. Evidence to keep: photo of the cluster with the lights.
What you must never do
- Do not attempt this professional task: Battery state-of-health report for the battery overheating light
- Do not attempt this professional task: Stored codes behind the battery overheating light
- Do not attempt this professional task: High-voltage isolation test after the battery overheating light
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.
Battery state-of-health report for the battery overheating light
What they doThe workshop pulls the high-voltage battery report with BYD's tool: estimated state of health (SOH), module voltages and the temperatures logged when the battery overheating light appeared.
They must show youthe battery state-of-health report with the date it was read.
In writingthe state of health read, whether any module is outside what BYD accepts and whether the proposed repair falls under the battery warranty.
Stored codes behind the battery overheating light
What they doAt a workshop with EV-trained technicians, they connect a BYD-capable diagnostic tool and read the stored and pending codes from the high-voltage battery management and its thermal system, with the time and conditions in which the battery overheating light was logged, before clearing anything.
They must show youthe code list with status, read while the battery overheating light is active or freshly logged.
In writingthe codes read, the system they point to and which test confirms the fault before any part is replaced for the battery overheating light.
High-voltage isolation test after the battery overheating light
What they doA technician qualified for high voltage, with the car unplugged and following BYD's safety procedure, measures the isolation of the high-voltage circuit with the manufacturer's equipment and inspects orange cables and connectors.
They must show youthe measured isolation value against BYD's specification and the condition of the cables and connectors checked.
In writingthe isolation test result, who did it with high-voltage training and whether it explains the battery overheating light.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Vehicles
- Brand
- BYD
- Product type
- Cars
Known code variants
- BYD ATTO 3 battery temperature warning
- BYD ATTO 3 testigo temperatura batería
- BYD batería alta tensión caliente
- BYD battery light flashing
- BYD battery overheating light
- BYD HV battery too hot
- BYD sobrecalentamiento batería
- BYD testigo batería parpadea
- High-voltage battery overheating warning light
- Testigo de sobrecalentamiento de la batería de alto voltaje
What it means
The 2025 BYD ATTO 3 owner's manual uses this light for high-voltage battery temperature. Steady: the temperature is too high and the car must be stopped to cool down. Flashing: stop immediately and leave the vehicle. BYD lists long climbs in hot weather, long stop-and-go traffic, frequent hard acceleration or braking, or driving a long time without a pause as conditions that can overheat it. While charging, charging stops automatically. The light does not tell demanding use from a fault: a diagnosis does.
Warnings and stop conditions
- Higheditorial warning
On an electric BYD, orange cables, the traction battery and their connectors carry high voltage: do not open, touch or disconnect them; only a workshop trained in high voltage should work on them.
Evidence: BYD ATTO 3 2025 owner's manual (left-hand drive)
- Criticalsource verified
If the light flashes, BYD recommends stopping immediately in a safe place and leaving the vehicle as soon as possible.
Evidence: BYD ATTO 3 2025 owner's manual (left-hand drive)
Sources and technical references
- 1
BYD ATTO 3 2025 owner's manual (left-hand drive)
BYD Auto Co. Ltd. · 2025 · manual
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