The Subaru e — Boxer 2.5L is a 2,498 cc, horizontally opposed (boxer) four — cylinder petrol — electric hybrid powertrain introduced in 2019. It pairs Subaru’s FB25 petrol engine with a compact electric motor integrated into the Lineartronic CVT. Key technologies include direct and port fuel injection (D — 4S), dual overhead camshafts (DOHC), and a 13.6 kW permanent — magnet synchronous motor. Total system output is 160 kW (218 PS) with 241 Nm of torque from the petrol engine…
Production years 2019–2021 meet Euro 6d TEMP standards; 2022–2025 models comply with Euro 6d .
The Subaru e-Boxer 2.5L is a 2,498 cc horizontally opposed four-cylinder petrol-electric hybrid engineered for compact SUVs (2019–2025). It combines D-4S dual injection with a 13.6 kW electric motor integrated into the CVT to deliver smooth low-speed electric assist and efficient highway cruising. Designed to meet Euro 6d TEMP and Euro 6d standards, it balances all-wheel-drive capability with reduced urban emissions.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,498 cc | |
Fuel type | Petrol (RON 95 min) | |
Configuration | Horizontally opposed-4, DOHC, 16-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 94.0 mm × 90.0 mm | |
Power output | 160 kW (218 PS) combined system output | |
Torque | 241 Nm @ 4,000 rpm (petrol only) | |
Fuel system | D-4S dual injection (direct + port) | |
Emissions standard | Euro 6d TEMP (2019–2021); Euro 6d (2022–2025) | |
Compression ratio | 12.0:1 | |
Cooling system | Water-cooled | |
Turbocharger | None | |
Timing system | Chain-driven DOHC | |
Oil type | Refer to vehicle handbook / manufacturer specification | |
Dry weight | 189 kg (including hybrid motor) |
The Subaru e-Boxer 2.5L was used across Subaru's SGP (Subaru Global Platform) with longitudinal mounting and exclusive to European markets. This engine received platform-specific adaptations—reinforced transmission mounts in the Forester and revised cooling ducts in the XV—and from 2022 the facelifted models adopted an updated inverter with improved thermal management, creating minor hybrid control differences. All adaptations are documented in OEM technical bulletins.
Engine Finders UK Ltd, which operates EngineCode.uk, can pass your enquiry to engine suppliers in the UK. The service is for vehicles in the United Kingdom, with UK delivery or fitting. This is a commercially connected service, and sending an enquiry does not confirm diagnosis or compatibility.
Diagnostic reminder: If a technician has recommended replacing the engine, you can send an enquiry to engine suppliers in the UK. Confirm the diagnosis first: an engine-code record does not diagnose a fault.
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.
Analysis derived from manufacturer technical service bulletins and industry workshop records. 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
The e-Boxer 2.5L is generally robust, with the FB25 petrol base known for durability. Early hybrid inverters (2019–2021) had thermal limitations, but 2022+ updates resolved most issues. Regular 12V AGM battery checks and using correct 0W-20 oil are key to longevity.
Main issues include hybrid inverter thermal derating (pre-2022), 12V battery drain, CVT shudder during EV transitions, and minor coolant leaks at the inverter heat exchanger. All are documented in Subaru service bulletins STS-004-2021 and related TIS updates.
Exclusively used in European-market Subaru XV (2019–2025) and Forester (2019–2025) as the 'e-Boxer' hybrid variant. Not sold in North America or Japan. Both models feature Symmetrical AWD and Lineartronic CVT with integrated electric motor.
No practical tuning path exists. The hybrid system’s ECU is tightly integrated with the CVT and traction control. ECU remapping is unsupported by Subaru and may disable hybrid functions or trigger limp mode. Power gains are not feasible without hardware redesign.
Official WLTP combined: ~6.5 L/100km (43 mpg UK). Real-world mixed driving typically yields 7.0–8.0 L/100km (34–40 mpg UK). Urban EV assist can lower city consumption, but highway efficiency is similar to non-hybrid FB25 due to added weight.
Yes. The FB25 petrol engine is an interference design. If the timing chain fails (rare but possible), valve-to-piston contact can cause catastrophic damage. However, the chain is robust and designed for life-of-engine service under normal conditions.
Subaru specifies 0W-20 synthetic oil meeting ILSAC GF-6A and API SP standards. Using incorrect viscosity (e.g., 5W-30) reduces fuel economy and may affect hybrid system calibration. Change intervals follow Subaru’s condition-based schedule (max 15,000 km).
Comprehensive technical documentation and regulatory references
EngineCode.uk is operated by Engine Finders UK Ltd. It provides engine-reference information and an optional commercial enquiry service. It is not an official manufacturer website. Check the record's sources and confirm vehicle-specific details before relying on it for parts, repairs or replacement.
Our editorial standard prioritises relevant manufacturer documentation and official regulatory sources. The sources and verification status for a record should be checked alongside the data.
A statement is not verified merely because a source is listed. Where supporting evidence is missing or conflicting, the record should identify that limitation. Please report unsupported or inconsistent information.
Transparency in gaps
A missing or unverified value does not mean the manufacturer has withheld it. We distinguish information not yet verified, information not available to us, and information explicitly not disclosed by the source.
Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
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.
GOV.UK: Vehicle Approval
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
Records are subject to review and correction. Source links, dates and verification notes should be read with the technical information. Our Editorial and Sourcing Policy explains our standards and review process.
Found an error or missing source? Report a problem with this page. Include the field or statement concerned and a supporting source if available. You can also email corrections@enginecode.uk.
Copyright and permissions
Images and other material may be protected by copyright. Attribution does not by itself grant permission to reuse material. If you believe material on this site infringes your rights, contact copyrights@enginecode.uk with the page URL and details of your claim. We will review the material and take appropriate action.
Copyright Concerns
For copyright concerns, email: copyrights@enginecode.uk
Our Privacy Policy explains how Engine Finders UK Ltd uses information from visits, vehicle lookups, enquiries and messages. Our Cookie Policy explains cookies and similar technologies and how to change your choices.
For access, correction, or deletion requests, email: gdpr@enginecode.uk
Trademark Notice
All trademarks, logos, and engine codes are the property of their respective owners. Use on this site is strictly for reference and identification.
Ownership and commercial services
EngineCode.uk is owned and operated by Engine Finders UK Ltd. Alongside our reference content, we offer an optional replacement-engine enquiry service through Engine Finders and may identify relevant services provided by businesses connected with us. These commercial connections are disclosed. Using an enquiry service is not required to read our reference content.
Engine Finders UK Ltd operates this website. Our optional enquiry service has a commercial purpose. Our Ownership and Commercial Disclosure explains the relationship between the reference website and that service. Participating suppliers pay a fee or subscription to participate on the network and receive quote requests.
Use this record as a starting point for identification. Specifications and vehicle applications may contain errors or omissions. Confirm the exact engine variant and compatibility using vehicle-specific documentation and a qualified supplier or technician.
All external links open in new tabs. Please verify current availability of resources.