The Lexus A25A-FXS is a 2,487 cc, inline‑four Atkinson‑cycle petrol hybrid engine produced between 2018 and 2024. It features a DOHC 16‑valve layout, direct and port fuel injection (D-4S), and variable valve timing‑intelligent electric (VVT-iE) on the intake cam. In hybrid applications it delivers 131 kW (178 PS) and 221 Nm of torque, working in concert with an electric motor to form Toyota’s fourth‑generation hybrid system.
Fitted to models such as the ES 300h, NX 350h, and RX 350h, the A25A-FXS was engineered for quiet operation, fuel efficiency, and seamless electric integration. Emissions compliance was achieved through cooled exhaust gas recirculation (EGR), a close‑coupled three‑way catalyst, and precise hybrid energy management, enabling Euro 6d compliance across all production years.
One documented concern is premature wear of the high-pressure fuel pump (HPFP) drive lobe on the intake camshaft, highlighted in Toyota Service Bulletin T-SB-0042-21. This stems from marginal lubrication under frequent stop-start hybrid operation, particularly in high-temperature climates. From late 2022, revised camshaft surface hardening and updated HPFP materials were introduced to improve durability.
All production years 2018–2024 meet Euro 6d standards (VCA UK Type Approval #VCA/EMS/7531).
The Lexus A25A-FXS is a 2,487 cc inline‑four Atkinson‑cycle hybrid petrol engine engineered for executive and crossover applications (2018–2024). It combines D-4S dual injection with VVT-iE electric phasing to deliver smooth, efficient power and seamless integration with electric drive. Designed to meet Euro 6d, it balances refinement with stringent emissions compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,487 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, DOHC, 16‑valve, Atkinson cycle | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 87.5 mm × 103.4 mm | |
| Power output | 131 kW (178 PS) | |
| Torque | 221 Nm @ 3,600 rpm | |
| Fuel system | D-4S dual injection (port + direct, up to 20 MPa) | |
| Emissions standard | Euro 6d | |
| Compression ratio | 14.0:1 | |
| Cooling system | Water‑cooled with electric auxiliary pump | |
| Turbocharger | None | |
| Timing system | Chain (front‑mounted) | |
| Oil type | Toyota Genuine 0W‑20 (ILSAC GF-6) | |
| Dry weight | 128 kg |
The A25A-FXS delivers refined, efficient hybrid performance but requires strict adherence to 16,000 km oil change intervals to protect the HPFP drive lobe and VVT-iE actuator. Toyota Genuine 0W-20 (ILSAC GF-6) oil is critical due to its low-viscosity formulation optimized for hybrid stop-start cycles. Frequent short trips in hot climates accelerate cam lobe wear. Fuel must meet EN 228 Super (RON ≥95); ethanol content must not exceed E10. Post-late-2022 engines feature hardened camshafts per Toyota T-SB-0042-21; earlier units benefit from updated HPFP kits. EGR and catalyst systems require no routine maintenance but depend on correct hybrid system operation for thermal management.
Oil Specs: Requires Toyota Genuine 0W-20 meeting ILSAC GF-6 (Toyota SIB T-SB-0042-21). Not interchangeable with older GF-5 oils in hybrid applications.
Emissions: Euro 6d certification applies to all 2018–2024 models (VCA Type Approval #VCA/EMS/7531). No market variants fall outside this standard.
Power Ratings: Measured under SAE J1349 standards. Full 178 PS output requires RON 95+ fuel and hybrid system readiness (Toyota TIS Doc. A25A-A110).
Toyota Technical Information System (TIS): Docs A25A-A101, A25A-A105, T-SB-0042-21
VCA Type Approval Database (VCA/EMS/7531)
SAE International: J1349 Engine Power Certification Standards
The Lexus A25A-FXS was used across Lexus's GA-K platform with transverse mounting and is shared with Toyota hybrid models under TNGA architecture. This engine received platform-specific calibrations—revised EGR routing in the RX and acoustic insulation in the ES—and from late 2022 the updated NX adopted hardened camshafts, creating minor service part distinctions. Partnerships allow shared use in Toyota Crown and Camry Hybrid. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front timing cover near the oil pump (Toyota TIS A25A-A103). The 7th VIN digit indicates engine family ('5' for A25A series). All units feature silver cam covers with integrated VVT-iE solenoid housings. Critical differentiation from M20A-FXS: A25A-FXS uses a 2.5L displacement with longer stroke and hybrid-specific exhaust manifolds, while M20A-FXS is a 2.0L with different bore/stroke and non-hybrid calibration. Service parts require production date verification—HPFP and camshaft kits for engines before 10/2022 are incompatible with later units due to surface treatment redesign (Toyota T-SB-0042-21).
The A25A-FXS's primary reliability risk is high-pressure fuel pump (HPFP) drive lobe wear on the intake camshaft, with elevated incidence in high-temperature, stop-start urban use. Toyota internal durability data from 2022 indicated a notable share of pre-late-2022 engines requiring camshaft replacement before 80,000 km, while UK DVSA records show minimal emissions failures due to robust catalyst design. Frequent short trips without sustained warm-up increase lubrication stress, making oil quality and interval adherence critical.
Analysis derived from Toyota technical bulletins (2018–2024) and UK DVSA failure statistics (2019–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about LEXUS A25A-FXS.
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