Hybrid system fault warning light or message: which faults cause it?

The most important among the documented faults: main relay of the power relay assembly (overheating and fire risk), in the 1.6 GDi híbrido (Kappa); clutch hydraulic actuator (HCA): leak or moisture with risk of short circuit and fire, in the 1.6 GDi híbrido (Kappa); hybrid system shutdown without fail-safe mode (loss of drive), in the 1.5 Hybrid; the car loses drive or stalls because of a hybrid system fail-safe mode fault, in the 1.8 Hybrid; the 12V battery drains on the C-HR and Corolla hybrids, in the 1.8 Hybrid; the 12 V battery goes flat if the car sits unused for several days, in the 2.0 and 2.5 Hybrid; safe mode due to battery controller calibration (loss of propulsion), in the 1.5 VC-Turbo e-Power; inverter (IPM module) overheating and loss of drive, in the 1.8 Hybrid.

Warning lights and alertsUrgency: Garage soon

Hybrid system fault warning light or message: causes and the faults that trigger it

16 documented faults cause it in 9 engines. The most important:

Critical severity: Main relay of the power relay assembly (overheating and fire risk) · 1.6 GDi híbrido (Kappa)
Critical severity: Clutch hydraulic actuator (HCA): leak or moisture with risk of short circuit and fire · 1.6 GDi híbrido (Kappa)
Critical severity: Hybrid system shutdown without fail-safe mode (loss of drive) · 1.5 Hybrid

What it means

Hybrid Toyotas and Lexuses show their own warning (a triangle or a message on the dashboard) when the hybrid system management electronics, such as the inverter, the battery or the electric motors, detect a fault, separate from the generic engine fault warning light. In some cases the car goes into a limited driving mode or loses electric drive.

General explanation from MotorFiable. How it shows up in each engine, with sources, is in the list of faults.

What to do now

Garage soon

If you also notice a loss of power or the car stalls, stop as soon as it is safe. Ask a garage with the right equipment to read the codes of the hybrid control unit, not just the petrol engine one.

Reviewed on 30 October 202625 sources How we work

Faults that cause it

Specific engine and gearbox faults, from most to least important (severity × frequency). Below each title, how the symptom shows up in that fault.

- Critical severityFrequency: Occasional1.6 GDi híbrido (Kappa)Main relay of the power relay assembly (overheating and fire risk)A poor relay contact can show up as a hybrid system warning on the dashboard; the sources mainly talk about the risk, not a specific warning.
Source for the symptom in the 1.6 GDi híbrido (Kappa)^[1]
- Critical severityFrequency: Occasional1.6 GDi híbrido (Kappa)Clutch hydraulic actuator (HCA): leak or moisture with risk of short circuit and fireADAC notes that the 2018 defect is announced by the hybrid system warning lighting up while driving.
Source for the symptom in the 1.6 GDi híbrido (Kappa)^[2]
- Critical severityFrequency: Occasional1.5 HybridHybrid system shutdown without fail-safe mode (loss of drive)It is usually accompanied by a hybrid system fault warning in the instrument cluster.
Source for the symptom in the 1.5 Hybrid^[3]
- Critical severityFrequency: Occasional1.8 HybridThe car loses drive or stalls because of a hybrid system fail-safe mode faultA hybrid system fault warning or message on the dashboard before or during the loss of drive.
Source for the symptom in the 1.8 Hybrid^[4]
- Medium severityFrequency: Very frequent1.8 HybridThe 12V battery drains on the C-HR and Corolla hybridsWith the 12V voltage very low, the hybrid system may refuse to start or go into fail-safe mode.
Source for the symptom in the 1.8 Hybrid^[5]
- Medium severityFrequency: Very frequent2.0 and 2.5 HybridThe 12 V battery goes flat if the car sits unused for several daysIf the 12 V voltage is insufficient, the hybrid system can lock itself into a safe mode or refuse to provide drive.
Source for the symptom in the 2.0 and 2.5 Hybrid^[5]
- High severityFrequency: Occasional1.5 VC-Turbo e-PowerSafe mode due to battery controller calibration (loss of propulsion)The e-Power system warning may appear on the instrument cluster.
Source for the symptom in the 1.5 VC-Turbo e-Power^[6]
- High severityFrequency: Occasional1.8 HybridInverter (IPM module) overheating and loss of driveHybrid system fault warning on the dashboard.Repair: €3,000
Source for the symptom in the 1.8 Hybrid^[4]
- Critical severityFrequency: Rare2.0 and 2.5 HybridLoosely tightened inverter bolt on the latest Camry Hybrid (US): fire riskDashboard warnings related to the hybrid system before a possible loss of power.
Source for the symptom in the 2.0 and 2.5 Hybrid^[7]
- Medium severityFrequency: OccasionalHonda IMA híbridoHigh-voltage IMA battery degradation and IMA warning light onThe IMA warning light comes on in the instrument cluster. According to DrivingElectric, even if the pack fails the car remains drivable and only the warning appears.
Source for the symptom in the Honda IMA híbrido^[8]
- Medium severityFrequency: Occasional1.5 VC-Turbo e-Powere-Power warning and limited mode due to incorrect state-of-charge readingThe e-Power system warning appears on the instrument cluster.
Source for the symptom in the 1.5 VC-Turbo e-Power^[6][9]
- Medium severityFrequency: OccasionalE-Tech HíbridoHybrid system electrical fault with "DANGER" warning and car won't startAn "electrical problem DANGER" message on the instrument panel.
Source for the symptom in the E-Tech Híbrido^[10]
- Medium severityFrequency: Occasional1.2 Dualjet and 1.2 VVTSHVS mild-hybrid system: recalls for the starter generator belt and softwareA hybrid system warning light or fault message would be the expected symptom of a control unit or starter generator fault.
Source for the symptom in the 1.2 Dualjet and 1.2 VVT^[11]
- High severityFrequency: Rare1.5 VC-Turbo e-Powere-Power generator failure with the car immobilisede-Power system fault with the car stopped on the road.
Source for the symptom in the 1.5 VC-Turbo e-Power^[12][13]
- High severityFrequency: Rare1.8 HybridDegradation or premature failure of the hybrid batteryHybrid system fault warning when the computer detects that the battery no longer responds normally.Repair: €2,800–€3,000
Source for the symptom in the 1.8 Hybrid^[14]
- Medium severityFrequency: RareM264/M25448 V battery of the mild-hybrid system: red battery warning and the car stoppingRed battery warning light followed by a message asking you to stop the vehicle.
Source for the symptom in the M264/M254^[15]

Faults elsewhere in the car that cause it

Suspension, brake, electronics and other faults on specific cars, from most to least important.

- Critical severityFrequency: CommonOpel Grandland IRisk of overheating and fire of the high-voltage battery on plug-in hybrid versions (2019-2022)A warning related to the hybrid system may come on; the source does not describe a reliable prior signal before the overheating risk.
Source for the symptom in the Opel Grandland I^[16]
- High severityFrequency: CommonRenault AustralErratic behaviour of the E-Tech hybrid automatic gearboxA dashboard warning of ‘electric motor overheating’, or a refusal to start with the message ‘risk of gearbox failure’.
Source for the symptom in the Renault Austral^[17][18]
- Critical severityFrequency: OccasionalKia Optima IVFault in the high-voltage battery management system of the plug-in hybrid OptimaIf the fault occurs, a warning light comes on in the instrument cluster.
Source for the symptom in the Kia Optima IV^[19]
- High severityFrequency: OccasionalNissan Juke IIHybrid battery failure that prevents startingThe electrical management system detects a fault in the high-voltage battery and prevents the car from starting.
Source for the symptom in the Nissan Juke II^[20]
- High severityFrequency: OccasionalToyota Prius IIShort circuit in the electric water pump of the hybrid cooling circuitWhen the pump stops working, several warning lights come on in the instrument cluster.
Source for the symptom in the Toyota Prius II^[19]
- High severityFrequency: OccasionalVolkswagen ArteonRecall for the high-voltage fuse on the Arteon eHybridThe data sheet describes no symptoms; these are preventive campaigns.
Source for the symptom in the Volkswagen Arteon^[21]
- Medium severityFrequency: OccasionalDacia BigsterStarting faults and multimode gearbox faults on the Bigster Hybrid 155The car does not start (sometimes after only a few kilometres), the combustion engine revs up without finding a gear, or the gearbox jerks.
Source for the symptom in the Dacia Bigster^[22]
- Critical severityFrequency: RareJeep RenegadeWater ingress into the mild hybrid system battery (1.5 MHEV, built 2022-2023)No warning is described; the risk is the battery overheating.
Source for the symptom in the Jeep Renegade^[23]
- Medium severityFrequency: OccasionalPeugeot 408Inconsistent electric range when charging the plug-in Hybrid versionThe electric range shown after a full charge can vary noticeably from one charge to another (for example, between 46 and 56 km according to one testimony, or another case with a drop from 45 to 26 km), and in some cases the charge does not start at all.
Source for the symptom in the Peugeot 408^[24]
- Critical severityFrequency: RareToyota Yaris IIIThe hybrid system's DC-DC converter can fail because of a faulty solder jointIf the 12 V auxiliary battery runs flat because of this fault, a hybrid system warning may come on and the car may lose drive while on the move.
Source for the symptom in the Toyota Yaris III^[25]

Which cars it appears in

These faults affect 9 engines. We have documented 42 models from 11 makes with some of the affected versions: open yours to see all its faults.

Engines

Cars with the affected versions

Dacia

Dacia JoggerEngine: E-Tech HíbridoYears: since 2023

Honda

Hyundai

Kia

Lexus

Lexus CTEngine: 1.8 HybridYears: 2010–2022

Mazda

Mazda 2 HybridEngine: 1.5 HybridYears: since 2022

Mercedes-Benz

Nissan

Renault

Suzuki

Toyota

See all Toyota models

Hybrid system warning: causes in your car

14 cars have several documented faults that cause this symptom. Choose yours to see only those that affect it, by engine and by year.

Hyundai 1

Hyundai Ioniq

Kia 1

Kia Niro I

Lexus 1

Lexus CT

Nissan 2

Renault 1

Renault Austral

Toyota 8

Hybrid system warning by brand

Other symptoms: warning lights and alerts

All symptoms

Has this happened to you? Tell us which fault it was, at how many kilometres and how much you paid: it helps other owners know what to expect. Report your fault.

Sources

Every fact on this page links to its source. If you find an error, let us know.

Kia Niro (2016-2018): relé principal con contactos deficientes (alerta Safety Gate 21/2019)Car-Recalls.eu (EU Safety Gate) · Other source · consulted 30 October 2026
Kia Niro 1.6 GDI Hybrid Spirit DCT6 (09/16 - 08/18): datos técnicos y retiradasADAC · Technical documentation · consulted 30 October 2026 · in German
Toyota Yaris 4 : fiabilité, pannes et rappelsFiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
Toyota Prius 3 : fiabilité, pannes et rappelsFiches-auto.fr · Motoring press · consulted 26 September 2026 · in French
Toyota C-HR : fiabilité, pannes et rappelsFiches-auto.fr · Motoring press · consulted 26 September 2026 · in French
Qashqai e-POWER Owner's Manual 2024: Service e-POWER system warningNissan Ireland · Manufacturer · published 2024 · consulted 29 October 2026
One loose bolt, 55,000 cars: Toyota's massive hybrid recall just got realCarscoops · Motoring press · published 23 December 2025 · consulted 27 September 2026
Used Honda Insight Mk2 buying guideDrivingElectric · Motoring press · published 24 October 2019 · consulted 8 October 2026
Nissanowski SUV z usterką systemu zarządzania akumulatoremAutokatalog.pl · Motoring press · published 2025 · consulted 29 October 2026 · in another language
Fiabilité et pannes de la Renault Clio 5Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
Suzuki Ignis (MF, ab 2016) – Bekannte Probleme & SchwachstellenGebrauchtwagenberater.de · Motoring press · consulted 27 September 2026 · in German
Fiabilidad y averías del Nissan Qashqai 3 (2021)fiches-auto.fr · Motoring press · consulted 29 October 2026 · in French
Brand New Nissan Qashqai e-Power Twice Stranded in a WeekSikayetvar · Owners' forum · published 22 March 2024 · consulted 29 October 2026
Toyota Auris : fiabilité, pannes et rappelsFiches-auto.fr · Motoring press · consulted 26 September 2026 · in French
Mild Hybrids 48 Volt ProblemsAutobiz Ireland · Motoring press · consulted 9 October 2026
Fiabilité Opel Grandland X (2017-2024), pannes et témoignagesFiches-Auto.fr · Technical documentation · consulted 27 September 2026 · in French
Renault Austral. Prise en charge d'un problème de boîte de vitesses sur la version hybrideL'argus · Motoring press · published 13 December 2025 · consulted 30 October 2026 · in French
Renault Austral: Probleme, Rückrufe und Erfahrungen der FahrerCarWiki.de · Other source · consulted 30 October 2026 · in German
Check a vehicle recall (recalls dataset since 1992)DVSA (Reino Unido) · Official body · consulted 5 October 2026
Fiabilité Nissan Juke 2 (2019-) : pannes recensées par les propriétairesFiches-auto.fr · Owners' forum · consulted 27 September 2026 · in French
Tous les problèmes sur Volkswagen Arteon 2017 (28 témoignages)fiches-auto.fr · Other source · consulted 5 October 2026 · in French
Fiabilité Dacia Bigster (2025) (18 témoignages)Fiches-auto.fr · Reliability study · consulted 30 October 2026 · in French
Jeep Renegade (2022-2023): batería híbrida suave y agua (Safety Gate 25/2023)car-recalls.eu · Official body · consulted 30 October 2026
Fiabilité Peugeot 408 (2023) : témoignages de pannesFiches-auto.fr · Reliability study · consulted 27 September 2026 · in French
Toyota Yaris (2018-2019): convertidor DC-DC del sistema híbridoCar-recalls.eu · Other source · published July 2019 · consulted 27 September 2026