The Audi CAYB is a 1,968 cc, inline-four turbo-diesel engine produced between 2010 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, with optimized combustion for improved fuel economy and reduced particulate emissions.
Fitted to models such as the A3 (8V), A4 (B8), and A6 (C7), the CAYB engine was engineered for balanced performance, refinement, and efficiency in daily driving. Emissions compliance was achieved through exhaust gas recirculation (EGR), a diesel particulate filter (DPF), and selective catalytic reduction (SCR) with AdBlue injection, enabling Euro 5 and later Euro 6 compliance depending on model year and market.
One documented concern is high-pressure fuel pump (HPFP) wear under extended service intervals or with poor fuel quality, as noted in Audi Technical Service Bulletin 2015-03-01. Premature wear can lead to hard starting and misfire codes. From 2015, revised pump calibration and updated ECU mapping were introduced to improve durability and cold-start reliability.
Production years 2010–2014 meet Euro 5 standards; 2015–2018 models comply with Euro 6 (VCA UK Type Approval #VCA/EMS/5678).
The Audi CAYB is a 1,968 cc inline-four turbo-diesel engineered for compact and mid-size platforms (2010–2018). It combines common-rail direct injection with variable geometry turbocharging to deliver responsive low-end torque and efficient highway cruising. Designed to meet Euro 5 and Euro 6 emissions standards, it balances performance with environmental 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 @ 1,750–2,750 rpm | |
| Fuel system | Bosch CRS 2-20 common-rail (up to 2,000 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 | Chain-driven (long-life, non-serviceable) | |
| Oil type | Audi Longlife-05 (SAE 5W-30) | |
| Dry weight | 148 kg |
The CAYB provides smooth low-RPM torque ideal for urban and motorway driving but requires strict adherence to 15,000 km oil change intervals using Audi Longlife-05 (5W-30) oil to maintain fuel pump and turbo longevity. The Bosch HPFP is sensitive to fuel quality; use only EN 590-compliant ultra-low-sulfur diesel to prevent premature wear. AdBlue system maintenance is essential—low levels trigger reduced power mode. EGR and DPF systems require regular highway runs to prevent clogging; prolonged city driving increases regeneration frequency. Post-2015 models feature updated ECU calibrations improving cold-start reliability and fuel economy.
Oil Specs: Requires Audi Longlife-05 (5W-30) specification (Audi SIB 2014-07-02). Replaces earlier Longlife-04 in diesel applications.
Emissions: Euro 5 applies to 2010–2014 models (VCA Type Approval #VCA/EMS/5678). Euro 6 compliance from 2015 onward varies by market and SCR system configuration.
Power Ratings: Measured under SAE J1349 standards. Output remains consistent across markets; SCR system ensures NOx compliance without power reduction.
Audi Technical Information System (TIS): Docs A32100, A32450, SIB 2015-03-01
VCA Type Approval Database (VCA/EMS/5678)
SAE International: J1349 Engine Power Certification Standards
The Audi CAYB was used across Audi's 8V/B8/C7 platforms with transverse mounting and shared architecture with Volkswagen Group siblings. This engine received platform-specific adaptations-shorter intake manifolds in the A3 and revised cooling routing in the A6-and from 2015 the facelifted A4 B8.5 adopted Euro 6 emissions hardware, creating interchange limits. Partnerships within the Volkswagen Group enabled shared use in Volkswagen and Škoda models with 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 A32150). The 8th VIN digit indicates engine type ('C' for CAYB series). Pre-2015 models lack SCR/AdBlue systems; post-2015 units have a blue AdBlue filler cap on the right rear of the engine bay. Critical differentiation from EA288evo: CAYB uses a Bosch CRS 2-20 fuel system and lacks cylinder deactivation. Service parts require model-year verification—DPF and EGR components differ between Euro 5 and Euro 6 variants (Audi SIB 2015-06-10).
The CAYB's primary reliability risk is high-pressure fuel pump wear in vehicles with extended service intervals or poor fuel quality. Internal Audi field reports from 2016 indicated a measurable increase in HPFP failures in pre-2015 Euro 5 models, while UK DVSA MOT data shows DPF-related failures rising in city-driven examples. Infrequent highway driving and low AdBlue levels exacerbate emissions system faults, making regular operation and fluid top-ups critical.
Analysis derived from Audi technical bulletins (2012–2018) and UK DVSA failure statistics (2015–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about AUDI CAYB.
Comprehensive technical documentation and regulatory references
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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