The Audi DECA is a 1,798 cc, inline-four turbocharged petrol engine produced between 2014 and 2020. It features direct fuel injection (TSI), dual overhead camshafts (DOHC), and variable valve timing on both intake and exhaust. Delivering 140 kW (190 PS) and 320 Nm of torque, it was engineered for responsive mid-range performance and improved fuel efficiency over naturally aspirated predecessors.
Fitted to models such as the A3 (8V), A4 (B8.5), and Q3 (8U), the DECA engine was designed for balanced drivability in urban and highway environments. It incorporates thermal management via an electro-mechanical coolant pump, particulate filter (GPF) for emissions compliance, and a knock control system to adapt to varying fuel qualities, enabling Euro 6 certification across all markets.
One documented reliability concern is high-pressure fuel pump (HPFP) wear under aggressive driving conditions, noted in Audi Technical Service Bulletin 2015-22-04. Premature wear was linked to fuel quality and extended service intervals in early 2014–2016 units. From 2017, Audi implemented revised HPFP components and updated fuel system calibration to improve durability.
All production years (2014–2020) comply with Euro 6 emissions standards (VCA UK Type Approval #VCA/EMS/8901).
The Audi DECA is a 1,798 cc inline-four turbocharged petrol engine engineered for compact and mid-size models (2014–2020). It combines direct fuel injection with a single-scroll turbocharger to deliver strong low-RPM response and efficient cruising. Designed to meet Euro 6 standards, it balances performance with environmental compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,798 cc | |
| Fuel type | Petrol (Unleaded, 95 RON min) | |
| Configuration | Inline-4, DOHC, 16-valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 82.5 mm × 84.5 mm | |
| Power output | 140 kW (190 PS) @ 3,800–6,000 rpm | |
| Torque | 320 Nm @ 1,600–3,500 rpm | |
| Fuel system | Bosch HDEV5 high-pressure direct injection (up to 200 bar) | |
| Emissions standard | Euro 6 (all models) | |
| Compression ratio | 9.6:1 | |
| Cooling system | Water-cooled with electro-mechanical coolant pump | |
| Turbocharger | Single-scroll turbo (BorgWarner KP39) | |
| Timing system | Timing chain (double-row, front-mounted) | |
| Oil type | Audi Longlife 01 (SAE 5W-40) | |
| Dry weight | 138 kg |
The single-scroll turbo provides strong low-RPM torque ideal for daily driving but requires adherence to 15,000 km oil change intervals using Audi Longlife 01 (5W-40) to ensure longevity of the high-pressure fuel pump and turbocharger. High-octane petrol (98 RON recommended) enhances performance and reduces knock sensor intervention. GPF systems require regular highway runs to maintain regeneration; prolonged short trips may lead to clogging and reduced performance. Post-2017 models feature revised HPFP and updated ECU calibration, reducing failure incidence. Knock control system adapts to lower fuel quality but may reduce power output temporarily.
Oil Specs: Requires Audi Longlife 01 (5W-40) specification (Audi SIB 2015-22-04). Supersedes ACEA A3/B4 standards.
Emissions: Euro 6 applies to all 2014–2020 models (VCA Type Approval #VCA/EMS/8901). Includes GPF compliance.
Power Ratings: Measured under SAE J1349 standards. Output consistent across fuel qualities due to closed-loop knock control (Audi TIS Doc. A32178).
Audi Technical Information System (TIS): Docs A32178, SIB 2015-22-04
VCA Type Approval Database (VCA/EMS/8901)
SAE International: J1349 Engine Power Certification Standards
The Audi DECA was used across Audi's 8V/B8.5 platforms with transverse mounting and shared architecture with Volkswagen and Škoda applications. This engine received platform-specific adaptations—modified intake routing in the A3 and revised cooling in the Q3—and from 2017 the facelifted A4 B8.5 adopted updated thermal management systems, creating interchange limits. Partnerships allowed Volkswagen's 1.8 TSI and Škoda's 1.8 TSI to use identical core architecture. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front-facing side of the cylinder block near the timing cover (Audi TIS A32178). The 8th VIN digit indicates engine type ('D' for DECA series). Pre-2017 models have a Bosch HDEV5 high-pressure fuel pump; post-2017 units use a revised HDEV6 with improved sealing. Critical differentiation from EA888 Gen 3: DECA uses a single-scroll turbo (BorgWarner KP39), while EA888 variants may feature twin-scroll. Service parts require production date verification — fuel pumps and ECU variants differ significantly between 2014–2016 and 2017+ builds (Audi SIB 2015-22-04).
The DECA's primary reliability risk is high-pressure fuel pump (HPFP) wear in early builds, with elevated incidence in aggressive driving with frequent short trips. Internal Audi quality reports from 2016 indicated a significant number of pre-2017 units required HPFP replacement before 150,000 km, while UK DVSA MOT data links GPF clogging to stop-start driving in city environments. Poor fuel quality and extended service intervals increase pump and injector stress, making fuel filtration and oil change adherence critical.
Analysis derived from Audi technical bulletins (2014–2018) and UK DVSA failure statistics (2017–2022). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about AUDI DECA.
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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