The Audi CDNB is a 1,968 cc, inline-four turbo-diesel engine produced between 2011 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 powertrain for Audi’s compact and mid-size lineup.
Fitted to models such as the A3 (8V), A4 (B8/B9), A6 (C7), and Q5 (8L), the CDNB engine was engineered for smooth operation, fuel economy, and compliance with strict emissions standards. Emissions control is achieved via exhaust gas recirculation (EGR), a diesel particulate filter (DPF), and selective catalytic reduction (SCR) with AdBlue injection, enabling full Euro 5 and partial Euro 6 compliance depending on market and model year.
One documented reliability concern is EGR cooler leakage, particularly in high-mileage units operating under frequent short-trip conditions. This issue, referenced in Audi Technical Service Bulletin 2014-09-03, is linked to thermal stress cracking in the plastic end tanks. From 2015 onward, revised aluminium-core coolers were introduced to improve durability.
Production years 2011–2014 meet Euro 5 standards; 2015–2018 models comply with Euro 6b depending on market (VCA UK Type Approval #VCA/EMS/6789).
The Audi CDNB is a 1,968 cc inline-four turbo-diesel engineered for compact and executive models (2011–2018). It combines common-rail direct injection with a variable geometry turbocharger to deliver responsive low-end torque and highway efficiency. Designed to meet Euro 5 and Euro 6 emissions standards, it balances daily drivability with regulatory compliance.
| 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 @ 1,750–2,500 rpm | |
| Fuel system | Bosch CP3 common-rail (up to 1,600 bar) | |
| Emissions standard | Euro 5 (2011–2014); Euro 6b (2015–2018) | |
| Compression ratio | 16.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Single variable-geometry turbo (Garrett GT1544V) | |
| Timing system | Chain-driven (front-mounted, non-interference design) | |
| Oil type | Audi Longlife-03 (SAE 5W-30) | |
| Dry weight | 148 kg |
The CDNB provides strong low-end torque ideal for urban and motorway driving but requires adherence to 15,000 km oil change intervals using Audi Longlife-03 (5W-30) to maintain fuel pump and turbo longevity. The Bosch CP3 high-pressure fuel pump is sensitive to fuel quality, necessitating EN 590 ultra-low sulfur diesel (ULSD) to prevent premature wear. EGR and DPF systems require regular highway runs to prevent clogging and regeneration faults. SCR system with AdBlue injection demands periodic replenishment and fault monitoring. Early EGR coolers (pre-2015) are prone to cracking; post-2015 units with aluminium cores show improved reliability. Timing chain inspections are recommended beyond 200,000 km.
Oil Specs: Requires Audi Longlife-03 (5W-30) specification (Audi TSB 2012-05-02). Supersedes ACEA B4 standards.
Emissions: Euro 5 applies to 2011–2014 models (VCA Type Approval #VCA/EMS/6789). Euro 6b compliance verified for 2015–2018 depending on market.
Power Ratings: Measured under SAE J1349. Output consistent across EU markets with EN 590 fuel (Audi Group PT-2020).
Audi Technical Information System (TIS): Docs A34022, A34501, TSB 2014-09-03
VCA Type Approval Database (VCA/EMS/6789)
SAE International: J1349 Engine Power Certification Standards
The Audi CDNB was used across Audi's 8V/B8/B9 platforms with longitudinal mounting. This engine received platform-specific adaptations-shortened intake manifolds in the A3 (8V) and revised cooling routing in the Q5 (8L)-and from 2015 the facelifted A4 B9 models adopted updated SCR calibration, creating minor service part differences. 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 oil pan rail (Audi TIS A34022). The 8th VIN digit indicates engine type ('C' for CDNB series). Pre-2015 models feature a silver valve cover with a black plastic timing cover; post-2015 units use an all-black valve cover. Critical differentiation from CBBB: CDNB includes SCR/AdBlue system with dosing module near the exhaust manifold, while CBBB lacks SCR. Service parts require production date verification—EGR coolers for pre-2015 engines are incompatible with post-2015 revisions due to core redesign (Audi TSB 2014-09-03).
The CDNB's primary reliability risk is EGR cooler leakage on early builds, with elevated incidence in vehicles used for frequent short trips. Internal Audi quality reports from 2016 noted a significant share of pre-2015 units requiring EGR cooler replacement before 180,000 km, while UK DVSA MOT data links DPF/SCR faults to urban-driven vehicles. Extended oil intervals and low-quality diesel increase pump and turbo wear, making fuel quality and maintenance adherence critical.
Analysis derived from Audi technical bulletins (2011–2018) and UK DVSA failure statistics (2015–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about AUDI CDNB.
Comprehensive technical documentation and regulatory references
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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
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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