How to Read a BYD Warning Light — the Rule That Comes First
BYD’s handbooks repeat the same sentence against almost every lamp, and it is the single most useful thing to understand before looking at any symbol: the light coming on when the vehicle is powered up is a self-check. It turning off after a few seconds is normal.
The corollary is what actually diagnoses the car. If the lamp does not illuminate during self-check, that is a fault. If it stays on after the self-check, that is a fault. If it comes on while driving, that is a fault. A brief flash at power-up means nothing — and a lot of unnecessary repairs start with someone misreading it.
So when you look at BYD warning lights, do not ask is it lit. Ask when did it light, and for how long. This page covers the full set of BYD dashboard symbols and their BYD warning light meanings — including the BYD fault indicators that appear only on electric and hybrid models and have no petrol-car equivalent.
Colour First, Symbol Second
The fastest way through a busy instrument cluster is to triage by colour before reading any icon.
Red — stop the vehicle safely, now
- ESC fault together with ABS and brake system warnings. BYD’s wording is blunt: stop immediately in a safe place and contact a dealer, because the vehicle becomes extremely unstable when braking and the ABS does not work.
- Parking system fault warning light — illuminates when brake fluid level is low and the braking system is faulty. Park the vehicle in a safe place immediately.
- Low oil pressure warning light — if it flashes or stays on, engine oil pressure is not what it should be.
- Low-voltage power system fault in the sense of a charging failure that will strand the car.
Amber — driveable, but investigate promptly
- Powertrain fault warning light — BYD’s caution is to try not to drive the vehicle and contact a dealer for troubleshooting as soon as possible.
- Engine fault warning light — by design it lights during self-check. Lit at any other time means a control system may be faulty, and BYD notes that even if you cannot feel a difference, continuing to operate can cause serious damage.
- Steering system fault warning light — steady on means the electric steering assistance has a fault.
- Motor coolant overheating indicator — coolant temperature too high. Park in a safe area until it goes out.
- BSD (blind spot detection) — lit means the system needs dealer inspection.
Green, blue and white — status, not fault
- EV, ECO, HEV, SPORT and NORMAL/OK indicators
- Position light and high beam indicators
- AVH indicator (white in standby, changes state when active)
- ACC standby and ACC status, TSR speed-limit recognition, lane navigation button
Operators regularly report “a light came on” that turns out to be HEV mode engaging. Knowing the status group by sight saves a scan.
The Electric-Specific Lamps
This is where a BYD instrument cluster differs from anything a combustion-trained technician has memorised. These positions have no petrol equivalent and are worth learning individually:
| Indicator | What it tells you |
|---|---|
| High-voltage battery low SOC | Traction battery state of charge is low |
| High-voltage battery overheating | Pack temperature above limits |
| High-voltage battery fault | Pack or its management system reports a fault |
| Motor overheating | Drive motor temperature above limits |
| Motor coolant overheating | Motor cooling circuit running hot — park until it clears |
| Low-voltage power system fault | Charging / DC / low-voltage supply problem |
| Driving power limit warning | Available power has been deliberately restricted |
| Motor fault | Drive motor fault logged |
| Charging connection indicator | Charge connection state |
Two of these deserve a note. Driving power limit is a derate, not a failure — the car has chosen to limit output because something is hot, low, or faulted, and the interesting question is which. And low-voltage power system fault is routinely misread as a 12V battery complaint; BYD describes it as a charging system / DC system / low-voltage supply problem where engine ignition can only be maintained until the battery is fully discharged. Their instructed action is to turn off the A/C and fan and drive to the nearest dealer.
Two Commonly Misread Lamps
TPMS warning light
The Tyre Pressure Monitoring System lamp has three distinct states and they mean different things:
- On at power-up, off a few seconds later — system is fine.
- On and staying on, with one or more pressure figures turning yellow on the display — low pressure in one or more tyres.
- On or flashing, with the cluster reading “Please check the tire pressure monitoring system” and pressures showing as “—” — the system itself has failed, which is not a tyre problem at all.
Third state misdiagnosed as first is a common source of wasted wheel-off inspections.
Smart key warning light
- On with the key outside the car — the cluster may ask “please confirm whether it is inside the vehicle”. Move the key in and it clears within seconds.
- Flashing when START/STOP is pressed — low battery in the key fob. This is the one people miss; it looks like an immobiliser fault and is a coin cell.
The Fault Messages That Are Not Lamps
On top of the lamps, BYD clusters display plain-language fault prompts with a recommended action. Several of them are unique to the platform and will not appear on a generic scan:
- Please check the OBC system — charging system fault. Check the charging connection and reconnect; if it persists, dealer.
- Please check the vehicle network — the vehicle may be disconnected from the data network; park immediately and contact a dealer.
- EV power limited — EV function restricted; contact a dealer immediately.
- Engine accessories function limited — engine accessory fault.
- Please check the memory system — memory system fault.
- For your safety, remote control driving is suspended — remote control driving abnormal; stop using it.
Also worth knowing for the hybrid models: long EV-only use can make the car request an engine start for maintenance, and the cluster states this explicitly. It is not a fault — it is the vehicle protecting itself.
What a Warning Lamp Actually Buys You
A lamp is a circuit, not a diagnosis. The cluster tells you which monitored system raised a flag; it does not tell you why. The useful sequence on a BYD is:
- Confirm the lamp is real — came on outside self-check, stayed on past a few seconds, or appeared while driving.
- Classify by colour — stop-now, book-in, or status.
- Pull the codes and read them against the module named by the lamp. Note that BYD-specific modules will not all respond to a generic OBD-II tool.
- Check the cheap cause before the expensive one — a 12V key fob battery, a TPMS sensor, or a fuse before a module.
And one honest limitation: an amber lamp that the customer can live with is still a fault. The vehicles are designed to limp, and “it still drives” is not evidence that nothing is wrong.
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Companion Pages: Putting These Documents to Work
The manuals above are the source. These pages are the extracted, workshop-ready versions of what is inside them.
- BYD high voltage shutdown procedure — Before touching anything on the high-voltage side — both disable methods, the 60-second de-energising window, and the fire and submersion procedures.
- BYD battery fire and thermal runaway response — A flooded or collision-damaged car arrives — the 24-hour cooling figure, the 45-minute release window, the 15 m isolation distance, and the four methods BYD rules out.
- BYD Dolphin fuse box diagram — Chasing an electrical fault — all 53 under-hood and 31 dashboard positions, and the component each one protects.
- BYD coolant type and capacity — Booking a cooling job — the published specification and fill volume for all ten current models, and which ones run two circuits.
- BYD Atto 3 service schedule — Taking a service booking — every interval, the four items with independent replacement cycles, and the severe-duty tightening.
Source
Compiled from the instrument cluster and warning light description sections of official BYD English-language owner’s handbooks, principally Sealion 5, with cross-reference to Seal, Dolphin and Sealion 7. Symbol sets and fault messages differ by model and trim — the principles here are consistent across the range, but confirm the specific lamp against the handbook for the vehicle in front of you.