The Audi CTBC is a 1,968 cc, inline-four turbo-diesel engine produced between 2008 and 2013. It forms part of the Volkswagen Group's EA189 engine family, designed for efficiency and responsive performance. Featuring common rail direct injection, variable geometry turbocharging (VGT), and DOHC valvetrain, it delivers 103 kW (140 PS) and 320 Nm of torque, with optimized low-end pull for urban drivability.
Fitted to models including the A3 (8P), A4 (B7/B8), A6 (C6), and Škoda/SEAT derivatives, the CTBC was engineered for balanced daily driving with strong fuel economy and smooth mid-range power delivery. Emissions compliance was achieved via exhaust gas recirculation (EGR), diesel particulate filter (DPF), and selective catalytic reduction (SCR) in certain variants, meeting Euro 5 standards across its production run.
One documented reliability concern is high-pressure fuel pump (HPFP) degradation under sustained high load or with marginal fuel quality. This issue, referenced in Audi Technical Service Bulletin 2011-15, is linked to wear in the CP3-type Bosch pump. Later production revisions incorporated improved lubricity specifications and updated calibration to mitigate premature wear.
Production years 2008–2013 meet Euro 5 standards (VCA UK Type Approval #VCA/EMS/5678).
The Audi CTBC is a 1,968 cc inline-four turbo-diesel engineered for compact and mid-size platforms (2008–2013). It combines common-rail direct injection with a variable geometry turbocharger to deliver responsive low-RPM torque and efficient highway cruising. Designed to meet Euro 5 emissions standards, it balances real-world performance with regulated cleanliness.
| 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) @ 4,000 rpm | |
| Torque | 320 Nm @ 1,500–2,500 rpm | |
| Fuel system | Bosch CP3 common-rail (up to 1,600 bar) | |
| Emissions standard | Euro 5 | |
| Compression ratio | 16.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Variable geometry turbo (Garrett GT1544V) | |
| Timing system | Timing belt (interval: 120,000 km or 5 years) | |
| Oil type | VW 504 00 / 507 00 (SAE 5W-30) | |
| Dry weight | 148 kg |
The CTBC provides strong low-end torque ideal for city driving but requires strict adherence to 15,000 km oil change intervals and high-quality 5W-30 oil meeting VW 504 00/507 00 standards to protect the turbo and fuel system. The timing belt must be replaced every 120,000 km or 5 years—failure risks severe engine damage due to interference design. The Bosch CP3 fuel pump is sensitive to water and contaminants in diesel, requiring regular use of ultra-low-sulfur diesel (EN 590). EGR and DPF systems need periodic regeneration; prolonged short trips may lead to clogging and limp mode. Pre-2010 models benefit from updated EGR cooler gaskets per Audi TSB 2011-15 to reduce leakage.
Oil Specs: Requires VW 504 00 / 507 00 specification (Audi SIB 23 10 12). Compatible with ACEA C3.
Emissions: Euro 5 certification applies to all CTBC models (2008–2013) (VCA Type Approval #VCA/EMS/5678).
Power Ratings: Measured under SAE J1349. Output consistent across markets with EU diesel (Audi TIS Doc. A32010).
Audi Technical Information System (TIS): Docs A32010, A32105, SIB 23 10 12
VCA Type Approval Database (VCA/EMS/5678)
SAE International: J1349 Engine Power Certification Standards
The Audi CTBC was used across Audi's 8P/B7/B8 platforms with longitudinal mounting and shared within the Volkswagen Group for transverse applications. This engine received platform-specific calibrations-fuel mapping in the A3 and enhanced cooling in the A6-and from 2011, certain A4 B8 models adopted revised EGR routing, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front face of the cylinder block, just below the exhaust manifold (Audi TIS A32010). The 8th VIN digit identifies the engine type ('B' for CTBC in Audi models). Pre-2010 units have a black plastic intake manifold; post-2010 variants may feature revised EGR routing with integrated cooler. Critical differentiation from other EA189 engines: CTBC uses a Garrett VGT turbo with a vacuum-actuated wastegate, whereas non-VGT variants use a fixed geometry turbo. Service parts require production date verification—timing belts for pre-2010 models are not interchangeable with later revisions due to tensioner design changes (Audi SIB 23 10 12).
The CTBC's primary reliability risk is high-pressure fuel pump wear, with elevated incidence in mixed urban/highway use. Internal Audi quality reports from 2012 indicated a measurable share of pre-2010 units requiring HPFP replacement before 150,000 km, while UK DVSA records show EGR-related faults contributing to emissions test failures in stop-start traffic. Extended oil intervals and low-quality diesel increase pump and EGR stress, making fuel quality and maintenance adherence critical.
Analysis derived from Audi technical bulletins (2008–2013) and UK DVSA failure statistics (2013–2020). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about AUDI CTBC.
Comprehensive technical documentation and regulatory references
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EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
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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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