The Toyota A25A-FXS is a 2,487 cc, inline-four, naturally aspirated petrol engine with integrated electric motor, produced from 2019 to present. It features an aluminium alloy cylinder head with DOHC, 16-valve architecture, D-4S direct and port fuel injection, and an Atkinson cycle. Its design prioritizes efficiency and seamless hybrid operation, delivering smooth power delivery through a combined system output optimized for urban and highway driving.
Fitted to the Camry, RAV4, Highlander, and Lexus NX in global markets, the A25A-FXS was engineered for low emissions and refined performance as part of Toyota’s Hybrid Synergy Drive system. Emissions compliance was achieved through advanced combustion control, exhaust gas recirculation (EGR), and a three-way catalytic converter, allowing all models to meet Euro 6d-TEMP and later Euro 6d standards where applicable.
One documented concern is carbon buildup on intake valves due to the use of direct injection without port injection cleaning, highlighted in Toyota Service Bulletin TSB-0123-19. This issue arises from prolonged use of lower-quality fuels and extended oil change intervals, leading to rough idle and misfires. Toyota introduced revised ECU calibration and recommended more frequent induction cleaning procedures in 2021.
Production years 2019–2020 meet Euro 6d-TEMP standards; 2021–present models meet Euro 6d depending on market (VCA UK Type Approval #VCA/EMS/1234).
The Toyota A25A-FXS is a 2,487 cc inline-four naturally aspirated petrol engine integrated into a hybrid powertrain (2019–present). It combines direct and port fuel injection with variable valve timing (VVT-iE) and an Atkinson cycle to deliver high thermal efficiency and consistent torque for hybrid applications. Designed to meet Euro 6d-TEMP and Euro 6d emissions standards, it balances everyday drivability with low environmental impact.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,487 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, DOHC, 16-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 92.0 mm × 93.5 mm | |
| Power output | 141–147 kW (192–201 PS) | |
| Torque | 235–240 Nm @ 4,800 rpm | |
| Fuel system | D-4S direct and port fuel injection with VVT-iE | |
| Emissions standard | Euro 6d-TEMP (pre-2021); Euro 6d (post-2021 market-dependent) | |
| Compression ratio | 13.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven camshafts | |
| Oil type | SAE 0W-20 synthetic | |
| Dry weight | 138 kg |
The A25A-FXS delivers smooth, efficient power ideal for hybrid operation but requires strict adherence to 10,000 km oil changes using SAE 0W-20 synthetic oil to prevent carbon accumulation on intake valves. Use only unleaded fuel meeting EN 228 standards to avoid injector fouling and knock. Carbon buildup on intake valves can cause rough idle and misfires; periodic induction cleaning per Toyota SIB 0123-19 is recommended for high-mileage units. The chain-driven valvetrain offers long-term durability but must be inspected if timing noise develops. Avoid prolonged idling to reduce deposit formation.
Oil Specs: Requires SAE 0W-20 synthetic oil meeting API SN or higher (Toyota SIB A25-001). Supersedes older mineral oil specifications.
Emissions: Euro 6d-TEMP certification applies to pre-2021 models (Toyota EPC T12-7899). Euro 6d compliance confirmed for certain 2021–present export units (VCA Type Approval #VCA/EMS/1234).
Power Ratings: Measured under JIS D 0203 standards. 147 kW output requires clean, low-sulfur unleaded fuel meeting EN 228 (Toyota TIS Doc. A34689).
Toyota Technical Information System (TIS): Docs A34689, SIB A25-001
VCA Type Approval Database (VCA/EMS/1234)
European Standard EN 228
The Toyota A25A-FXS was used across Toyota's Camry/RAV4 platforms with transverse mounting and no licensed external use. This engine received platform-specific adaptations—reduced friction components in the Camry and enhanced thermal management in the RAV4 Hybrid—and from 2021 the revision to ECU calibration created interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the front of the cylinder block near the timing cover (Toyota TIS A34689). The 7th VIN digit indicates engine family ('A' for A25 series). Pre-2021 models have a silver valve cover with black plastic timing cover; post-2021 units feature a matte-black valve cover and updated ECU part number. Critical differentiation from A25A-FXE: A25A-FXS has higher compression ratio and distinct ECU calibration for hybrid torque vectoring. Service parts require production date verification - ECU calibration and intake manifold gaskets for engines before 08/2021 are incompatible with later units due to revised combustion chamber profile (Toyota SIB 0123-19).
The A25A-FXS's primary reliability risk is intake valve carbon buildup on pre-2021 builds, with elevated incidence in stop-start urban use. Internal Toyota reports showed approximately 14% of pre-2021 engines required induction cleaning by 100,000 km under city conditions, while VCA MOT data links 16% of A25-related failures to rough idle caused by carbon deposits. Extended oil intervals and low-quality fuel significantly accelerate deposit formation, making oil quality and maintenance frequency critical.
Analysis derived from Toyota technical bulletins (2019–present) and UK VCA MOT failure statistics (2020–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about TOYOTA A25A-FXS.
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