Toyota Aqua NHP10 warning lights: what each one means
21 warning lights and 14 multi-information display messages from Toyota's own owner's manual, grouped by how urgently the manufacturer says to act, with the printed page or original web section for each so you can check the original.
Japan-market Aqua NHP10 as covered by the November 2015 manual edition. Earlier and later editions may differ. Lights marked equipment-dependent are fitted only on some grades.
A warning light is the car reporting a condition, not a diagnosis of a specific part. If braking, steering or engine behaviour changes, stop where it is safe. If you are unsure, follow the manual and contact a dealer. This page does not replace a professional inspection.
A fault in the SRS airbag or pretensioner seat-belt system.
What the manual says to do
Have the car inspected by a Toyota dealer immediately.
Hybrid battery cooling maintenance lightHave it inspected promptly
Manual name: メンテナンス・点検警告灯 · printed p.344 · fitted on some grades only
When it lights
The traction-battery cooling parts need maintenance: the filter may be clogged, the cooling intake blocked or a duct gap present.
What the manual says to do
Have the traction-battery cooling parts serviced by a Toyota dealer.
Pre-crash safety (PCS) warning lightHave it inspected promptly
Manual name: PCS 警告灯 · printed p.340 · fitted on some grades only
When it lights
Flashing with a buzzer: a pre-crash safety fault.
Flashing without a buzzer: the system is paused, for example by dirt, fog, condensation or ice on the windscreen near the front sensor, or a sensor temperature outside its range.
On: VSC or pre-crash safety (or both) is switched off.
What the manual says to do
Fault: have the car inspected by a Toyota dealer immediately.
Paused: clean the windscreen near the sensor, or wait for the sensor area to cool.
Switched off: turn VSC and pre-crash safety back on.
Smart entry & start system indicatorHave it inspected promptly
Manual name: スマートエントリー＆スタートシステム表示灯 · yellow · printed p.340, 346 · fitted on some grades only
When it lights
Flashing yellow for 15 seconds with a buzzer: a smart entry & start or steering-lock fault.
Flashing yellow for 15 seconds with one beep: the electronic key battery is low.
What the manual says to do
Fault: have the car inspected by a Toyota dealer immediately.
Low key battery: replace the key battery (manual p.304).
Check and correct
Often caused by something you can check or correct yourself; see the conditions listed.
Charging warning light (auxiliary battery low)Check and correct
Manual name: 充電警告灯（点滅または点灯） · printed p.341, 344
When it lights
Flashing or on: the auxiliary (12V) battery is undercharged.
What the manual says to do
If it goes out after a few seconds, keep the hybrid system running for about 15 minutes or more to charge the battery.
If it stays on, start the hybrid system using the flat-battery procedure on p.395.
If it flashes frequently the 12V battery may be deteriorating: have it checked by a Toyota dealer.
Brake override / drive-start control warning lightCheck and correct
Manual name: ブレーキオーバーライドシステム／ドライブスタートコントロール警告灯 · printed p.342 · fitted on some grades only
When it lights
Flashing: a brake override or drive-start control fault.
On: accelerator and brake pressed together, or a shift made with the accelerator pressed.
What the manual says to do
Flashing: have the car inspected by a Toyota dealer immediately.
On: release the accelerator or brake pedal.
Low traction battery warning lightCheck and correct
Manual name: 駆動用電池残量低下警告灯 · printed p.341 · fitted on some grades only
When it lights
The shift lever has been in N for a long time and the traction battery charge has dropped.
What the manual says to do
The battery cannot charge in N: shift to P when stopping for a long time.
If the READY indicator is off, shift to P and restart the hybrid system.
Parking brake warning lightCheck and correct
Manual name: パーキングブレーキ警告灯 · printed p.339, 343
When it lights
The parking brake is applied; a buzzer sounds above 5 km/h.
What the manual says to do
Release the parking brake.
Low fuel warningCheck and correct
Manual name: 燃料残量警告灯 · printed p.342
When it lights
About 5 L or less of fuel remains; a buzzer sounds.
What the manual says to do
Refuel.
Seat belt reminderCheck and correct
Manual name: シートベルト非着用警告灯 · printed p.342–343
When it lights
The driver or front passenger seat belt is unfastened (buzzer from about 20 km/h).
What the manual says to do
Fasten the seat belt; a front passenger must also wear theirs.
Multi-information display messages
When the master warning light comes on, the display shows a message. Most messages on this car are pictorial or Japanese, so each entry gives the manual's own description in Japanese, an English translation of that description and Toyota's response. The English is a CarFactBook translation, not the exact on-screen wording, unless a quoted display text is shown. If the message reappears after you have followed the response, the manual says to contact a dealer.
Stop safely and contact a dealer
Hybrid system abnormality
Manual description: ハイブリッドシステムの異常 · printed p.347
Shown with a warning buzzer.
Toyota: stop in a safe place immediately and contact a Toyota dealer. The manual names no failed component for this message.
Engine coolant temperature abnormally high
Manual description: エンジン冷却水高温異常 · printed p.347
Stop in a safe place immediately and follow the manual's overheating section (printed p.402). Do not open a hot cooling-system cap.
Engine oil pressure abnormal
Manual description: エンジンオイル圧力の異常 · printed p.348
Shown with a buzzer when oil pressure is abnormally low.
Stop in a safe place immediately and contact a Toyota dealer.
Have it inspected immediately
Smart entry & start system or steering lock system abnormality
Manual description: スマートエントリー&スタートシステムの異常／ステアリングロックシステムの異常 · printed p.349 · fitted on some grades only
A buzzer sounds. Have it inspected by a Toyota dealer immediately.
Toyota lists a clogged filter, a blocked cooling intake or a gap in the duct as possible causes.
Have the traction-battery cooling parts maintained by a Toyota dealer. Do not open the battery enclosure; this message is not a battery-health result.
Shown when starting the hybrid system
12V auxiliary (starting) battery charge low
Manual description: 補機バッテリーが充電不足 · Display text quoted in the manual: 「補機バッテリ（始動用）充電不足 取扱書を確認して下さい」 · printed p.354, 356
Shown for about 6 seconds.
If it clears after a few seconds: keep the hybrid system operating for about 15 minutes or more to charge the 12V battery.
If it does not clear: start the hybrid system using the manual's flat 12V battery procedure (printed p.395).
If it appears frequently, Toyota warns the 12V battery may be deteriorating and should be inspected by a dealer.
Smart key and power-switch messages
Tried to start without the electronic key, or the key is not working normally
Manual description: 電子キーを携帯していないか、電子キーが正常に作動しない状態でハイブリッドシステムを始動しようとした · printed p.357 · fitted on some grades only
Carry the electronic key and start the hybrid system.
Source: Toyota Motor Corporation, Aqua owner's manual (Japan), November 2015 edition. Open the original manual ↗ (Japanese). English wording on this page is a CarFactBook paraphrase of the manual, checked on 2026-10-27.
