The Audi CDTB is a 1,968 cc, inline-four turbo-diesel engine produced between 2012 and 2018. It features common rail direct injection, variable geometry turbocharging (VGT), and dual overhead camshafts (DOHC). In standard tune, it delivers 103 kW (140 PS) and 320 Nm of torque, serving as a refined and efficient diesel unit in Audi's compact and mid-size lineup.
Fitted to models such as the A3 (8V), A4 (B8/B9), and Q3 (8U), the CDTB was engineered for balanced performance, fuel economy, and low noise, vibration, and harshness (NVH). Emissions compliance was achieved via exhaust gas recirculation (EGR), a diesel particulate filter (DPF), and selective catalytic reduction (SCR) in certain markets, enabling Euro 5 and later Euro 6 compliance depending on specification.
One documented concern is high-pressure fuel pump (HPFP) degradation under low-fuel conditions, particularly in early-build units. This issue, referenced in Audi Technical Service Bulletin 2013-04-02, stems from inadequate lubrication when fuel levels remain below ¼ tank. From 2014, revised maintenance guidelines emphasized strict adherence to fuel quality and minimum level thresholds to mitigate wear.
Production years 2012–2015 meet Euro 5 standards; 2015–2018 models comply with Euro 6 depending on market (VCA UK Type Approval #VCA/EMS/6789).
The Audi CDTB is a 1,968 cc inline-four turbo-diesel engineered for compact and executive models (2012–2018). It combines common-rail direct injection with a variable geometry turbocharger to deliver responsive low-end torque and motorway efficiency. Designed to meet Euro 5 and Euro 6 emissions standards, it balances real-world drivability with regulated environmental performance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,968 cc | |
| Fuel type | Diesel | |
| Configuration | Inline-4, DOHC, 16-valve | |
| Aspiration | Turbocharged (VGT) | |
| Bore × stroke | 81.0 mm × 95.5 mm | |
| Power output | 103 kW (140 PS) @ 3,500–4,000 rpm | |
| Torque | 320 Nm @ 1,500–3,000 rpm | |
| Fuel system | Bosch CRS 2.0 common rail (up to 1,600 bar) | |
| Emissions standard | Euro 5 (pre-2015); Euro 6 (2015–2018) | |
| Compression ratio | 16.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Single variable-geometry turbo (Garrett GT1544V) | |
| Timing system | Timing belt (service interval 120,000 km) | |
| Oil type | Audi Longlife-04 (5W-30) | |
| Dry weight | 149 kg |
The VGT turbo delivers strong low-RPM pull ideal for urban and highway driving but requires strict adherence to 15,000 km oil change intervals using Audi Longlife-04 (5W-30) to protect the high-pressure fuel system. The Bosch CRS 2.0 pump is sensitive to low fuel levels and poor-quality diesel, necessitating use of EN 590-compliant fuel to prevent HPFP wear. Timing belt replacement is mandatory at 120,000 km or 5 years; failure risks valve-to-piston contact. EGR, DPF, and SCR systems require regular longer runs to prevent clogging and regeneration issues. Post-2015 models benefit from revised EGR cooling calibration reducing carbon accumulation.
Oil Specs: Requires Audi Longlife-04 (5W-30) specification (Audi TIS A34801). Supersedes ACEA B4-08 and C3 standards.
Emissions: Euro 5 applies to pre-2015 models (VCA Type Approval #VCA/EMS/6789). Euro 6 compliance confirmed for 2015–2018 units in UK market.
Power Ratings: Measured under SAE J1349. Output consistent across markets with ULSD fuel (Audi Group PT-2023).
Audi Technical Information System (TIS): Docs A34121, A34561, A34801, TSB 2013-04-02
VCA Type Approval Database (VCA/EMS/6789)
SAE International: J1349 Engine Power Certification Standards
The Audi CDTB was used across Audi's 8V/B8/B9 platforms with longitudinal mounting and shared architecture with Volkswagen and Škoda transverse applications. This engine received platform-specific adaptations-shorter intake manifolds in the A3 and revised EGR routing in the A4-and from 2015 the facelifted A4 B9 adopted updated DPF regeneration logic, creating software compatibility limits. Partnerships enabled Volkswagen's 2.0 TDI CR and Škoda's 2.0 TDI to use identical core architecture. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front of the cylinder block near the timing belt cover (Audi TIS A34801). The 7th digit of the VIN identifies the engine family ('C' for CDTB series). Pre-2015 units have a silver valve cover; post-2015 models use black. Critical differentiation from CCDA: CDTB uses Bosch CRS 2.0 injection with grey high-pressure lines, while CCDA uses same pump but earlier ECU calibration. Service parts require model-year verification—timing belts for B8 A4 are not interchangeable with B9 due to tensioner design changes (Audi TSB 2014-06-13).
The CDTB's primary reliability risk is high-pressure fuel pump wear under low-fuel operation, with elevated incidence in short-trip urban use. Internal Audi service reports from 2014 indicated a significant number of HPFP failures before 150,000 km in vehicles consistently operated below ¼ tank, while UK DVSA records show EGR-related faults contributing to emissions test failures in city-driven A3s. Extended idling and poor fuel quality increase pump and injector stress, making fuel discipline and oil interval adherence critical.
Analysis derived from Audi technical bulletins (2012–2018) and UK DVSA failure statistics (2015–2022). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about AUDI CDTB.
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