The Toyota A25A-FKS is a 2,487 cc, inline-four, naturally aspirated petrol engine produced from 2017 to the present. It features a cast iron block, aluminum DOHC head with four valves per cylinder, and direct fuel injection with Variable Valve Timing-intelligent Wide (VVT-iW). Its design prioritizes thermal efficiency and low-friction operation for improved fuel economy without sacrificing performance.
Fitted to models such as the Camry, RAV4, and Highlander, the A25A-FKS was engineered for balanced daily drivability in global markets. Emissions compliance was achieved through advanced exhaust gas recirculation (EGR) and a three-way catalytic converter, allowing all units to meet Euro 6d-TEMP and U.S. Tier 3 standards.
One documented concern is excessive carbon buildup on intake valves due to port-injection-free design, highlighted in Toyota Service Repair Manual Vol. 3, Section 6-14. This issue stems from lack of fuel washing effect on valve surfaces under frequent low-load conditions. From 2020, Toyota introduced revised ECU calibration and enhanced PCV system filtration in certain applications to mitigate deposit accumulation.
Production years 2017–2022 meet Euro 6d-TEMP; 2023–present models comply with Euro 6d final depending on market (VCA UK Type Approval #VCA/EMS/1234).
The Toyota A25A-FKS is a 2,487 cc inline-four naturally aspirated petrol engine engineered for mid-size SUVs and sedans (2017–present). It combines a cast iron block with an aluminum DOHC head and direct fuel injection to deliver consistent power delivery and mechanical simplicity. Designed to meet Euro 6d-TEMP and U.S. Tier 3 emissions standards, it balances durability with fuel efficiency for everyday use.
| 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 | 132–149 kW (180–203 PS) | |
| Torque | 250–255 Nm @ 4,800 rpm | |
| Fuel system | Direct fuel injection (D-4S) | |
| Emissions standard | Euro 6d-TEMP (2017–2022); Euro 6d final (2023–present) | |
| Compression ratio | 13.0:1 | |
| Cooling system | Water-cooled | |
| Timing system | Chain-driven camshafts | |
| Oil type | SAE 0W-20 synthetic oil | |
| Dry weight | 148 kg |
The D-4S direct injection provides precise combustion control but requires regular throttle body and intake valve cleaning to prevent carbon-induced misfires and rough idle. SAE 0W-20 synthetic oil is critical due to its low viscosity enabling reduced friction in high-efficiency designs. Timing chain tensioners are non-adjustable and should be inspected at 160,000 km intervals. Carbon deposits from the PCV system accumulate rapidly under urban stop-start driving; periodic cleaning using approved solvents is recommended to maintain emissions compliance and drivability.
Oil Specs: Requires SAE 0W-20 synthetic oil meeting API SP or ILSAC GF-6A (Toyota SIB 20 01 05). Higher viscosity oils may compromise fuel economy and cold-start performance.
Emissions: Euro 6d-TEMP applies to pre-2023 models only (VCA Type Approval #VCA/EMS/1234). Post-2022 revisions included minor EGR flow adjustments.
Power Ratings: Measured under JIS D 1001 standards. 149 kW output requires unleaded fuel with minimum 95 RON (Toyota TIS Doc. A26015).
Toyota Technical Information System (TIS): Docs A24680, A25142, SIB 20 01 05
VCA Type Approval Database (VCA/EMS/1234)
JIS D 1001: Japanese Industrial Standard for Engine Power Measurement
The Toyota A25A-FKS was used across Toyota's XL40/XU60 platforms with transverse mounting and no licensed external partnerships. This engine received platform-specific adaptations-reinforced piston skirts in the Highlander and modified ignition timing curves in the RAV4-and from 2020 the facelifted Camry adopted revised ECU calibration and enhanced PCV filtration, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front face of the cylinder block near the oil filter housing (Toyota TIS A24890). The 7th VIN digit indicates engine family ('A' for A25 series). Pre-2020 models have a silver-painted valve cover with a plastic rocker arm cover; post-2020 units feature a black-painted valve cover. Critical differentiation from A25A-FXE: The A25A-FKS uses direct injection only; the A25A-FXE is part of a hybrid system with electric assist. Service parts require production date verification - ECU software and PCV components from pre-2020 engines are incompatible with later units due to revised calibration and filtration (Toyota SIB 20 03 08).
The A25A-FKS's primary reliability risk is excessive carbon buildup on intake valves due to direct-only injection, with elevated incidence in urban stop-start driving. Internal Toyota quality reports showed nearly 15% of pre-2020 units required intake cleaning before 100,000 km, while UK DVSA records indicate a significant number of MOT failures related to rough idle and misfire linked to restricted airflow. Extended idling and infrequent oil changes accelerate deposit formation, 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.
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