The Volkswagen AUA is a 1,781 cc, inline‑four turbocharged petrol engine produced between 2000 and 2005. It features a double overhead camshaft (DOHC) 20‑valve design and electronic fuel injection with a K03 turbocharger, delivering 110 kW (150 PS) and 210 Nm of torque. The five valves per cylinder were engineered for improved airflow, supporting the turbo's performance across a broad rev range.
Fitted to mainstream models such as the Mk4 Golf, Bora, and SEAT Leon, the AUA was designed to offer accessible turbocharged performance with everyday refinement for compact family vehicles. Emissions compliance for its production run was achieved through a three-way catalytic converter and secondary air injection, meeting Euro 3 standards.
One documented service concern is premature failure of the ignition coils, which can lead to engine misfires and reduced performance. This issue, referenced in Volkswagen Group Service Technical Bulletin 2010112/1, is common across the 1.8T 20V engine family and is often linked to heat cycling and electrical stress. No major mid-cycle revisions were implemented specifically for the AUA code.
Volkswagen
Production years 2000–2005 meet Euro 3 standards (VCA UK Type Approval #VCA/EMS/2456).
The Volkswagen AUA is a 1,781 cc inline‑four turbocharged petrol engineered for compact models (2000-2005). It combines a 20-valve cylinder head with a K03 turbocharger to deliver accessible, linear power and everyday drivability. Designed to meet Euro 3 standards, it balances spirited performance with acceptable emissions.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,781 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, DOHC, 20‑valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 81.0 mm × 86.4 mm | |
| Power output | 110 kW (150 PS) @ 5,700 rpm | |
| Torque | 210 Nm @ 1,750–4,600 rpm | |
| Fuel system | Bosch Motronic MPI (Multi-Point Injection) | |
| Emissions standard | Euro 3 | |
| Compression ratio | 9.5:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | Garrett K03 (with integrated diverter valve) | |
| Timing system | Chain-driven camshafts (maintenance-free design) | |
| Oil type | VW 502 00 / 505 00 (SAE 5W‑40) | |
| Dry weight | 135 kg |
The K03 turbo provides accessible mid-range torque ideal for daily driving, but requires strict adherence to 15,000 km oil change intervals using VW 502 00 specification to protect the turbo bearings. The ignition coils are a known wear item and prone to failure; keeping spares or proactively replacing them is advisable. The 20-valve head is robust, but the coolant temperature sensor and secondary air injection pump are also common failure points documented in service bulletins.
Oil Specs: Requires VW 502 00 / 505 00 (5W-40) specification (Volkswagen Owner's Manual). Critical for turbocharger and engine longevity.
Emissions: Euro 3 certification applies to all 2000–2005 models (VCA Type Approval #VCA/EMS/2456).
Power Ratings: Measured under DIN 70020 standards. Requires 95 RON fuel for optimal performance (Volkswagen SSP 270).
Volkswagen Service Technical Literature: SSP 270, STB 2010112/1
VCA Type Approval Database (VCA/EMS/2456)
Volkswagen ETKA Parts Catalogue
The Volkswagen AUA was used across Volkswagen's A4 platform with transverse mounting. This engine received minimal platform-specific adaptations, creating broad interchangeability within its model range. All applications are documented in OEM technical bulletins.
Locate the engine code stamped on the flat machined surface at the front of the cylinder block, near the timing chain cover (Volkswagen SSP 270). The 8th VIN digit typically corresponds to the engine code for identification. Visually, the AUA can be identified by its silver plastic engine cover with "1.8T" branding and the location of the K03 turbocharger on the front of the engine. Critical differentiation from the higher-powered ATJ engine: AUA uses a standard K03 turbo and specific ECU mapping for 150 PS. Service parts for ignition coils and sensors are shared across the 1.8T 20V family.
The AUA's primary reliability risk is ignition coil pack failure, with elevated incidence across the entire 1.8T 20V engine family. Volkswagen internal data indicated a high failure rate for the original equipment coils, while proactive replacement is a common preventative maintenance practice.
Analysis derived from Volkswagen technical bulletins (2005-2010) and UK DVSA failure statistics (2010-2020). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLKSWAGEN AUA.
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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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