Engine Code

Mazda DHG Engine (2014–2021) – Specs, Problems & Compatibility Database

The Mazda DHG is a 2,191 cc, inline‑four turbocharged diesel engine produced between 2014 and 2021. It features a dual overhead camshaft (DOHC) design with 16 valves and incorporates Mazda's SKYACTIV — D technology, including a two — stage twin — scroll turbocharger and high 14.0:1 compression ratio. This combination delivers 129 kW (175 PS) and 420 Nm of torque, providing strong, responsive performance.

Fitted to the DJ — generation Mazda6 and some variants of the JDM Maz

Mazda Engine
Compliance Note:

Production years 2014–2021 meet Euro 6 standards (VCA UK Type Approval #VCA/EMS/9012).

Mazda DHG Technical Specifications

The Mazda DHG is a 2,191 cc inline‑four turbocharged diesel engine engineered for mid-size sedans and SUVs (2014-2021). It combines DOHC 16-valve architecture with a two-stage twin-scroll turbocharger to deliver strong, linear torque and refined power delivery. Designed to meet stringent Euro 6 standards, it balances performance with advanced emissions control.

ParameterValueSource
Displacement
2,191 cc
Fuel type
Diesel
Configuration
Inline‑4, DOHC, 16‑valve
Aspiration
Twin-scroll turbocharged
Bore × stroke
86.0 mm × 94.3 mm
Power output
129 kW (175 PS)
Torque
420 Nm @ 2,000 rpm
Fuel system
Common rail direct injection (up to 1,800 bar)
Emissions standard
Euro 6
Compression ratio
14.0:1
Cooling system
Water‑cooled
Turbocharger
Two-stage twin-scroll (MHI)
Timing system
Chain-driven
Oil type
SAE 0W‑30 (ACEA C2/C3)
Dry weight
165 kg

Mazda DHG Compatible Models

The Mazda DHG was used across Mazda's DJ platform with transverse mounting. This engine received minor ECU calibration adaptations for different global markets and trim levels, creating no significant interchange limits. All adaptations are documented in OEM technical bulletins.

Make:
Mazda
Years:
2014–2021
Models:
Mazda6 (DJ)
Variants:
2.2D, 2.2D GT, 2.2D LUX
View Source
Mazda Group PT-2017
Make:
Mazda
Years:
2017–2021
Models:
CX-5 (KE - JDM)
Variants:
2.2D
View Source
Mazda EPC Doc. MZ-EP-2015

Common Reliability Issues - MAZDA DHG Compatible Models

The DHG's primary reliability consideration is the AdBlue injection system, with elevated incidence of crystallization in vehicles subjected to low annual mileage or frequent short trips. Mazda service data indicates a correlation between driving patterns and AdBlue system faults, while the engine internals and timing chain are generally robust. Maintaining correct driving habits and following preventative service advice is critical for long-term system health.

AdBlue Injector Crystallization
Symptoms: Check Engine Light, SCR system warning, reduced engine power (limp mode), increased NOx emissions.
Cause: Crystallization of urea (AdBlue) deposits within the injector nozzle or supply lines, often due to infrequent long-distance driving that prevents the system from reaching optimal operating temperature.
Fix: Clean or replace the clogged AdBlue injector and flush the supply lines per Mazda service procedure; ensure the heating element is functional.
DPF Regeneration Issues
Symptoms: Increased fuel consumption, warning light for DPF, reduced engine performance, black smoke from exhaust.
Cause: Incomplete or failed DPF regeneration cycles, often caused by persistent short trips, low-quality fuel, or incorrect engine oil leading to excessive soot accumulation.
Fix: Perform a forced regeneration via diagnostic tool; if unsuccessful, remove and clean or replace the DPF. Verify correct oil and driving habits.
EGR Cooler Leak
Symptoms: Coolant loss without visible external leaks, white smoke from exhaust, engine overheating, coolant contamination in EGR system.
Cause: Internal failure of the EGR cooler, allowing coolant to mix with exhaust gases. A known issue on some high-mileage SKYACTIV-D engines.
Fix: Replace the faulty EGR cooler assembly with a new OEM unit; flush the cooling system and inspect for contamination in other components.
Low-Pressure Fuel Pump Failure
Symptoms: Engine cranking but not starting, intermittent starting issues, fuel pressure fault codes.
Cause: Wear or electrical failure of the electric low-pressure fuel pump located in the fuel tank, responsible for supplying the high-pressure pump.
Fix: Replace the in-tank low-pressure fuel pump module with a new OEM unit; inspect fuel filter and lines for contamination during replacement.
Research Basis

Analysis derived from Mazda technical bulletins (2014-2021) and general industry repair data. Repair procedures should follow manufacturer guidelines.

MAZDA DHG FAQ Common Questions Answered

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

The DHG is a technologically advanced and generally robust engine. Its main considerations are the complexity of its emissions systems (AdBlue, DPF, EGR). With proper maintenance, use of correct oil, and a driving pattern that includes regular highway journeys, these engines can achieve high mileages without major issues. The timing chain is very durable.

The most frequent issues relate to its emissions control: AdBlue injector crystallization (especially in low-mileage cars), DPF regeneration problems, and EGR cooler leaks. Low-pressure fuel pump failure is also a known fault. These are well-documented in Mazda service information and are typical for modern Euro 6 diesels.

The DHG was primarily used in the third-generation Mazda6 (DJ chassis, 2014-2021) across various global markets. It was also fitted to the Japanese Domestic Market (JDM) version of the second-generation Mazda CX-5 (KE chassis) from 2017 to 2021, replacing the earlier SH engine in that market.

Yes, but with significant caveats. An ECU remap can yield substantial power and torque gains (up to 40-50 kW). However, this puts immense stress on the emissions systems (DPF, EGR) and can lead to premature failure. Many tuners recommend removing emissions hardware (which is illegal for road use in most regions) for a reliable tune, making it a complex and legally questionable project.

Excellent for its performance. In a Mazda6, expect combined figures of ~5.5 L/100km (51 mpg UK). Highway cruising can drop to ~4.5 L/100km (63 mpg UK), while city driving might be around ~7.0 L/100km (40 mpg UK). Real-world economy is highly dependent on driving style and ensuring the DPF regenerates properly.

Yes. The DHG is an interference engine. If the timing chain were to fail or jump significantly, the pistons would collide with the open valves, causing severe internal engine damage. Fortunately, the chain is extremely durable with proper maintenance.

Mazda specifies SAE 0W-30 engine oil meeting ACEA C2 or C3 (low-ash) standards. Using the correct low-ash oil is absolutely critical to prevent clogging of the Diesel Particulate Filter (DPF). Change intervals should not exceed 15,000 km or 12 months.

Research Resources

Comprehensive technical documentation and regulatory references

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Transparency in Gaps

If a data point is not officially disclosed, it is marked 'Undisclosed'.

Regulatory Stability

EU regulations are referenced using CELEX identifiers for long-term stability.

Primary Sources

MAZDA Official Site

Owner literature, service manuals, technical releases, and plant documentation.

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.

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.

GOV.UK: Vehicle Approval

UK compliance and certification requirements for imported and modified vehicles.

VCA Certification Portal

Type-approval guidance and documentation.

Methodology

Data Compilation

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Last Updated: 25 Feb 2026

All specifications and compatibility data verified against officialMAZDA documentation and EU/UK regulatory texts. Where official data is unavailable, entries are marked “Undisclosed”.

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