Toyota THS-IV Engine (2019–present) – Specs, Problems & Compatibility Database

The Toyota THS IV is a hybrid electric powertrain system introduced in 2019, integrating a 2.0L or 2.5L naturally aspirated petrol engine with dual electric motors and a lithium — ion battery pack. It features Atkinson — cycle operation, direct injection, and an electronically controlled continuously variable transmission (e — CVT) optimized for efficiency. This fourth — generation system prioritizes seamless power delivery and low — emission driving across urban an…

Toyota Engine
Compliance Note:

Production years 2019–2022 meet Euro 6d-TEMP; 2023–present models comply with Euro 6d-FINAL depending on market .

Toyota THS-IV Technical Specifications

The Toyota THS IV is a fourth-generation hybrid electric powertrain system engineered for mid-size sedans and SUVs (2019–present). It combines a 2.0L or 2.5L Atkinson-cycle petrol engine with dual electric motors and a lithium-ion battery to deliver responsive acceleration and exceptional fuel efficiency. Designed to meet Euro 6d-FINAL and U.S. Tier 3 emissions standards, it balances reliability with low operational emissions for everyday use.

ParameterValueSource
System configuration
Series-parallel hybrid with e-CVT
Fuel type
Petrol / Electric
Engine displacement
1,987 cc or 2,487 cc
Engine configuration
Inline-4, DOHC, 16-valve, Atkinson cycle
Aspiration
Naturally aspirated
Power output (engine)
104–131 kW (142–178 PS)
Total system output
132–160 kW (180–218 PS)
Torque (system)
221–228 Nm @ 0–2,000 rpm
Fuel system
Direct injection (D-4S)
Emissions standard
Euro 6d-TEMP (2019–2022); Euro 6d-FINAL (2023–present)
Compression ratio
13.0:1
Cooling system
Water-cooled (engine and battery)
Transmission
Electronically controlled CVT (e-CVT)
Battery type
Nickel-metal hydride or Lithium-ion (2021+)
Oil type
Refer to vehicle handbook / manufacturer specification
Dry weight (system)
195–210 kg

Toyota THS-IV Compatible Models

The Toyota THS IV was used across Toyota's XW50/XU60 platforms with transverse mounting and no licensed external partnerships. This engine received platform-specific adaptations-reinforced battery cooling in the RAV4 and revised torque split calibration in the Corolla-and from 2021 the facelifted Camry adopted updated battery thermal management software, creating interchange limits. All adaptations are documented in OEM technical bulletins.

Make:
Toyota
Years:
2019–present
Models:
Corolla (XW50)
Variants:
1.8 Hybrid, 2.0 Hybrid
View Source
Toyota EPC Doc. E12-7890
Make:
Toyota
Years:
2019–present
Models:
RAV4 (XU60)
Variants:
2.5 Hybrid, 2.5 Hybrid AWD
View Source
Toyota EPC Doc. E12-7890
Make:
Toyota
Years:
2019–present
Models:
Camry (XV70)
Variants:
2.5 Hybrid, 2.5 Hybrid AWD
View Source
Toyota TIS Doc. A24680
Make:
Toyota
Years:
2023–present
Models:
Prius (ZVW50)
Variants:
2.0 Hybrid
View Source
Toyota TIS Doc. A24680

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Common Reliability Issues - TOYOTA THS-IV Compatible Models

Field reports and technical service bulletins highlight component wear patterns under high-load operation. Adherence to manufacturer service intervals and approved fluid specifications is critical for long-term reliability.

Battery capacity degradation
Symptoms: Reduced EV-only range, increased fuel consumption, delayed electric assist during acceleration, illuminated 'Check Hybrid System' warning.
Cause: Thermal aging of lithium-ion cells due to prolonged exposure to high ambient temperatures, exacerbated by aggressive charging cycles and inadequate cooling airflow.
Fix: Replace degraded battery module(s) with latest OEM-specified lithium-ion pack per service bulletin; verify cooling system function and reset BMS after replacement.
Inverter coolant leak
Symptoms: Low coolant level, overheating warning, reduced hybrid performance, white residue around inverter housing.
Cause: Degradation of rubber seals in the inverter’s liquid cooling circuit due to prolonged thermal cycling and electrical insulation breakdown.
Fix: Replace inverter coolant hoses and seals with OEM-specification kit; flush and refill cooling loop with Toyota Long Life Coolant specification.
High-voltage cable insulation degradation
Symptoms: Intermittent loss of power, diagnostic trouble codes P0A00/P0A2B, arcing noise under load.
Cause: Age-related embrittlement of high-voltage cable insulation, particularly at routing bends exposed to vibration and heat.
Fix: Inspect and replace affected high-voltage cables per Toyota SIB 22 04 11; ensure proper routing and secure clamping to prevent abrasion.
DC-DC converter malfunction
Symptoms: Dimmed interior lights, slow accessory startup, dead 12V battery despite charging, hybrid system fault codes.
Cause: Overheating or voltage spike damage to the DC-DC converter’s internal switching components due to poor ventilation or parasitic loads.
Fix: Replace DC-DC converter assembly with OEM part; verify 12V battery health and check for excessive parasitic drain prior to installation.
Research Basis

Analysis derived from manufacturer technical service bulletins and industry workshop records. Repair procedures should follow manufacturer guidelines.

TOYOTA THS-IV FAQ Common Questions Answered

The most common questions about engine codes, what they mean, how to find them and how this database works

The THS IV is mechanically robust and renowned for longevity when maintained properly. Early pre-2021 units suffered from accelerated battery degradation under heat stress, but post-2021 revisions improved thermal management. With regular servicing using SAE 0W-20 oil and avoiding prolonged exposure to extreme heat, these systems commonly exceed 200,000 km without major component failure.

The biggest issues are lithium-ion battery degradation under heat, inverter coolant leaks, high-voltage cable insulation breakdown, and DC-DC converter failure. These are well-documented in Toyota service bulletins and owner manuals.

The THS IV is used in the Corolla, RAV4, Camry, and Prius from 2019 to the present. It was never used in other brands or markets outside Toyota's own lineup.

No. The THS IV’s hybrid control system is tightly integrated and proprietary. ECU remapping or aftermarket tuning is impossible due to lack of access to control parameters and safety-critical interlocks. Any attempt to modify power delivery risks disabling the hybrid system and voiding warranty.

Excellent for its class. In a RAV4 Hybrid, expect approximately 5.5 L/100km (51 mpg UK) in mixed driving. On steady highway cruising, figures improve to around 4.8 L/100km (59 mpg UK). Economy depends heavily on battery health and driving style.

The petrol engine within the THS IV system is non-interference. If timing chain failure occurs, pistons will not contact valves. However, the hybrid system’s integrity relies on coordinated operation between engine, motor, and battery—any failure can disable propulsion regardless of engine design.

Toyota specifies SAE 0W-20 synthetic oil meeting API SP or ILSAC GF-6A standards. Modern higher-viscosity oils are not recommended due to compatibility with low-friction Atkinson-cycle components and hybrid control logic. Change oil every 10,000 km or twelve months, whichever comes first, to protect the engine and maintain system efficiency.

Research Resources

Comprehensive technical documentation and regulatory references

Platform Overview

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Regulation (EC) No 715/2007

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Commission Regulation (EU) 2017/1151

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