Toyota A25A-FKS Engine (2017–present) – Specs, Problems & Compatibility Database

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…

Toyota Engine
Compliance Note:

Production years 2017–2022 meet Euro 6d-TEMP; 2023–present models comply with Euro 6d final depending on market .

Toyota A25A-FKS Technical Specifications

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.

ParameterValueSource
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
Refer to vehicle handbook / manufacturer specification
Dry weight
148 kg

Toyota A25A-FKS Compatible Models

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.

Make:
Toyota
Years:
2017–present
Models:
Camry (XL40)
Variants:
2.5L SE, 2.5L XLE
View Source
Toyota EPC Doc. E12-7890
Make:
Toyota
Years:
2018–present
Models:
RAV4 (XU60)
Variants:
2.5L Dynamic, 2.5L Hybrid
View Source
Toyota EPC Doc. E12-7890
Make:
Toyota
Years:
2019–present
Models:
Highlander (XU70)
Variants:
2.5L Limited, 2.5L Platinum
View Source
Toyota TIS Doc. A24680

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Common Reliability Issues - TOYOTA A25A-FKS 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.

Carbon buildup on intake valves
Symptoms: Rough idle, hesitation under acceleration, stalling at stops, illuminated check engine light with P0300/P0301 codes.
Cause: Lack of fuel washing effect on intake valves due to direct injection; oil vapors from PCV system condense and polymerize into hard carbon deposits.
Fix: Remove and clean intake manifold and valves with approved solvent; replace PCV valve and inspect hoses per Toyota SIB 20 03 08.
Timing chain elongation and noise
Symptoms: Rattling noise from front of engine, especially on cold start, inconsistent valve timing.
Cause: Non-adjustable chain tensioner wears over time, allowing chain slack to develop beyond tolerance levels.
Fix: Inspect chain tension and replace chain and sprockets if stretch exceeds 0.5 mm per link per OEM procedure.
Coolant leaks from water pump seal
Symptoms: Coolant puddle beneath engine, rising temperature gauge, sweet odor inside cabin.
Cause: Age-related hardening of the water pump shaft seal, exacerbated by coolant contamination or extended service intervals.
Fix: Replace water pump assembly with OEM part; flush cooling system and refill with Toyota Long Life Coolant specification.
Throttle body malfunction
Symptoms: Erratic idle, limp mode, delayed throttle response.
Cause: Carbon accumulation on throttle plate and bore, disrupting airflow measurement and electronic control.
Fix: Clean throttle body with approved solvent; perform electronic throttle adaptation reset after service.
Research Basis

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

TOYOTA A25A-FKS FAQ Common Questions Answered

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

The A25A-FKS is mechanically robust and renowned for longevity when maintained properly. Early pre-2020 units suffered from intake valve carbon buildup, but post-2020 revisions improved PCV filtration and ECU calibration. With regular oil changes using SAE 0W-20 synthetic oil and periodic intake cleaning, these engines commonly exceed 250,000 km without major work.

The biggest issues are carbon buildup on intake valves, timing chain rattle from stretched chains, water pump seal leaks, and throttle body malfunctions. These are well-documented in Toyota service bulletins and owner manuals.

The A25A-FKS was used in the Camry, RAV4, and Highlander from 2017 to the present. It was never used in other brands or markets outside Toyota's own lineup.

Limited. The A25A-FKS’s direct-injection design and high compression ratio restrict tuning potential. Basic upgrades like a free-flowing exhaust or K&N air filter offer marginal gains. ECU remapping is impossible due to the lack of aftermarket support and complex emissions controls. Significant power increases require swapping to a turbocharged engine.

Excellent for its class. In a RAV4, expect approximately 7.0 L/100km (40 mpg UK) in mixed driving. On steady highway cruising, figures improve to around 6.0 L/100km (47 mpg UK). Economy depends heavily on intake cleanliness and tire pressure.

No. The A25A-FKS is a non-interference engine. If the timing chain fails, pistons will not contact the valves. While valve damage is unlikely, the engine will stop running immediately and require chain replacement before restarting.

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 components and variable valve timing systems. Change oil every 10,000 km or twelve months, whichever comes first, to protect the valvetrain and minimize PCV system contamination.

Research Resources

Comprehensive technical documentation and regulatory references

Platform Overview

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EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).

GOV.UK: Vehicle Approval & V5C

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Regulatory Context

Regulation (EC) No 715/2007

Euro emissions framework for vehicle type approval.

Commission Regulation (EU) 2017/1151

WLTP and RDE testing procedures for emissions certification.

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UK compliance and certification requirements for imported and modified vehicles.

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Type-approval guidance and documentation.

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