The Audi BAS is a 1,968 cc, inline — four turbo — diesel engine produced between 2009 and 2013. It features common rail direct injection, a variable geometry turbocharger (VGT), and double overhead camshafts (DOHC). In standard tune, it delivered 88 kW (120 PS) and 280 Nm of torque, serving as an entry — level diesel option for Audi's compact and mid — size vehicles.
Fitted to models such as the A3 (8P), A4 (B8), and A6 (C7), the BAS engine was engineered for fuel efficiency and urb…
Production years 2009–2010 meet Euro 5 standards; 2011–2013 models include SCR-based aftertreatment for enhanced NOx control .
The Audi BAS is a 1,968 cc inline-four turbo-diesel engineered for compact and executive models (2009–2013). It combines common-rail direct injection with a single variable-geometry turbocharger to deliver responsive low-RPM torque and efficient urban driving. Designed to meet Euro 5 emissions standards, it balances economy with regulated environmental performance.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,968 cc | |
Fuel type | Diesel | |
Configuration | Inline-4, DOHC, 16-valve | |
Aspiration | Turbocharged | |
Bore × stroke | 81.0 mm × 95.5 mm | |
Power output | 88 kW (120 PS) @ 4,000 rpm | |
Torque | 280 Nm @ 1,750–2,500 rpm | |
Fuel system | Bosch CRS 2-18 common-rail (up to 1,600 bar) | |
Emissions standard | Euro 5 (SCR from 2011) | |
Compression ratio | 16.5:1 | |
Cooling system | Water-cooled | |
Turbocharger | Single variable-geometry turbo (Garrett GT1544V) | |
Timing system | Chain-driven (double-row, front-mounted) | |
Oil type | Refer to vehicle handbook / manufacturer specification | |
Dry weight | 165 kg |
The Audi BAS was used across Audi's 8P/B8/C7 platforms with longitudinal mounting and shared architecture with Volkswagen and Škoda for transverse applications. This engine received platform-specific adaptations-shorter intake tracts in the A3 and revised cooling routing in the A6-and from 2011 the facelifted A4 B8.5 adopted SCR-based aftertreatment, creating interchange limits. Partnerships enabled Volkswagen's 2.0 TDI and Škoda's 2.0 CR TDI to use identical core architecture. All adaptations are documented in OEM technical bulletins.
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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 BAS is generally robust when maintained properly, but pre-2011 models are prone to high-pressure fuel pump failures beyond 150,000 km. Later SCR-equipped variants show improved emissions system durability. Regular oil changes with VW 504 00/507 00 oil and use of quality diesel are essential for longevity.
Key issues include high-pressure fuel pump degradation, EGR and intake carbon buildup, turbo actuator sticking, and oil leaks from valve cover gaskets. These are documented in Audi service bulletins, particularly SIB 2011-03-01 for fuel system concerns.
The BAS was used in the A3 (8P), A4 (B8), and A6 (C7) from 2009 to 2013. It was also shared with Volkswagen Golf (MK6) and Škoda Octavia (A5) in transverse applications. All variants produce 88 kW (120 PS) and 280 Nm.
Aftermarket ECU tuning is common on the BAS platform, but increasing boost or altering engine parameters accelerates component wear, impacts emissions compliance, and may void vehicle warranties. Any modifications should be evaluated carefully by a qualified specialist.
In combined driving, the BAS achieves approximately 4.8–5.4 L/100 km (59–52 mpg UK). Highway efficiency can reach 4.2 L/100 km (67 mpg UK). Real-world consumption depends on driving style, but it remains competitive for its era.
Yes, the BAS is an interference engine. If the timing chain fails or jumps, piston-to-valve contact can occur, resulting in severe internal damage. The chain is generally durable, but tensioner wear should be inspected during major services.
Audi specifies SAE 5W-30 oil meeting VW 504 00 / 507 00 standards. This low-ash formulation is critical for DPF and SCR system longevity. Oil changes should be performed every 15,000 km or annually to ensure optimal engine protection.
Comprehensive technical documentation and regulatory references
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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.
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