The Lexus AC27A — FXS is a 2,487 cc, inline‑four Atkinson‑cycle petrol engine paired with an electric motor in a series — parallel hybrid system, produced from 2020 onward. It features Toyota’s Dynamic Force architecture with high thermal efficiency (41%), VVT — iE on the intake cam, direct and port fuel injection (D — 4S), and cooled exhaust gas recirculation (EGR). The combined system output is 164 kW (223 PS), with electric — only operation up to 140 km/h under light load.
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All production years (2020–present) meet Euro 6d emissions standards (VCA UK Type Approval #VCA/EMS/5678).
The Lexus AC27A-FXS is a 2,487 cc inline‑four Atkinson‑cycle hybrid petrol engine engineered for premium compact SUVs (2020–present). It combines D-4S dual injection with VVT-iE variable valve timing to deliver smooth electric-assisted acceleration and low urban emissions. Designed to meet Euro 6d standards, it balances refinement, efficiency, and hybrid drivability.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,487 cc | |
Fuel type | Petrol (RON 95 min) | |
Configuration | Inline‑4, DOHC, 16‑valve, Atkinson cycle | |
Aspiration | Naturally aspirated | |
Bore × stroke | 87.5 mm × 103.4 mm | |
Power output | 118 kW (160 PS) petrol + 46 kW (62 PS) electric = 164 kW (223 PS) combined | |
Torque | 207 Nm (petrol) + 207 Nm (electric) = 221 Nm system torque | |
Fuel system | D-4S (direct + port injection) | |
Emissions standard | Euro 6d | |
Compression ratio | 14.0:1 | |
Cooling system | Water‑cooled (dual circuit: engine + inverter) | |
Turbocharger | None | |
Timing system | Chain-driven DOHC | |
Oil type | Toyota Genuine Motor Oil 0W‑20 (ILSAC GF-6 / API SP) | |
Dry weight | 138 kg (engine only) |
The Lexus AC27A-FXS was used exclusively in Lexus's AZ20 platform with transverse mounting and shared with Toyota for the Harrier Hybrid in Japan and select Asian markets. This engine received platform-specific adaptations—reinforced subframes for NVH control in the NX 350h and revised inverter mounting in the Harrier—with no facelift revisions affecting core compatibility as of 2025. All adaptations are documented in OEM technical bulletins.
The AC27A-FXS's primary reliability risk is inverter coolant pump seal degradation in early builds, with elevated incidence in high-temperature climates. Toyota internal field data from 2022 indicated a small but notable failure rate before 60,000 km, while UK DVSA records show minimal MOT impact due to hybrid system redundancy. Extended high-load hybrid operation increases thermal stress on the pump, making periodic inspection critical.
Analysis derived from Toyota technical bulletins (2020–2024) and UK DVSA failure statistics (2021–2023). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
Yes. The AC27A-FXS is based on Toyota’s proven Dynamic Force hybrid architecture with strong long-term reliability. Early 2020–2021 models had a minor inverter pump issue (addressed under service campaign), but otherwise the engine shows excellent durability. Regular 12V battery checks and correct ATF WS fluid changes ensure hybrid system longevity.
The main documented issue is inverter coolant pump seal wear in early builds (TSC‑2022‑04). Other minor concerns include 12V AGM battery fatigue in city driving and slow transaxle fluid degradation. Carbon buildup is minimal due to D-4S injection. All are manageable with scheduled maintenance.
The AC27A-FXS is used exclusively in the Lexus NX 350h (AZ20 series, 2020–present). It is also found in the mechanically identical Toyota Harrier Hybrid (XU80) in Japan and Asia. No other Lexus or Toyota models currently use this specific hybrid variant.
No. The AC27A-FXS hybrid system is tightly integrated with the transaxle and ECU; no safe or OEM-supported tuning paths exist. Power output is managed by the hybrid control unit, and modifications risk inverter or battery damage. Toyota does not endorse performance remapping for this powertrain.
Excellent. The NX 350h achieves ~5.3 L/100km combined (WLTP), or ~53 mpg UK. Real-world mixed driving typically yields 45–55 mpg (UK). Electric-only mode covers short urban trips, while highway cruising uses the efficient Atkinson cycle. Economy depends heavily on driving style and battery state.
Yes. Like all modern Toyota/Lexus engines, the AC27A-FXS is an interference design. However, it uses a maintenance-free timing chain with no known wear issues. Chain failure is extremely unlikely under normal conditions, but catastrophic if it occurs.
Toyota specifies 0W‑20 synthetic oil meeting ILSAC GF-6 and API SP standards (e.g., Toyota Genuine Motor Oil). This low-viscosity oil is critical for VVT-iE solenoid response and fuel economy. Change intervals are 16,000 km or 12 months under normal conditions.
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