2020–2026 Audi A3 (8Y) Service and Repair Manual PDF

Description

Audi A3 (Typ 8Y) Service and Repair Manual — 2020 to 2026

The fourth-generation A3 is the first one that genuinely resists the old approach. It runs a 48-volt mild-hybrid system on some engines, shift-by-wire gear selection, MIB3 infotainment, and a driver-assistance suite that needs recalibrating after work as ordinary as a windscreen replacement.

None of this is difficult. All of it is unforgiving if you guess. A 2020s Audi does not forgive a mechanic working from a 2010s mental model.

What the A3 8Y is

Launched in 2020 on the MQB evo platform, the 8Y is sold as a five-door Sportback and a four-door Saloon. A facelift arrived in 2024, updating the front and rear styling, the infotainment software and parts of the driver-assistance package.

The engine range is smaller than the 8V’s but more varied in how it delivers power: three- and four-cylinder petrol units, several with 48-volt mild hybrid assistance, plug-in hybrid variants, and the EA288 evo diesel with twin-dosing AdBlue injection.

Note: this set covers the standard A3 range. The S3 and RS3 are separate cars with different engines, gearboxes and drivetrains, and they have their own dedicated documentation — links at the bottom of this page.

Engines covered

Model	Engine	Family	Notes
30 TFSI	1.0 TFSI	EA211 evo	Three-cylinder, belt-driven
35 TFSI	1.5 TFSI	EA211 evo	150 PS, 48V mild hybrid on some
40 TFSI quattro	2.0 TFSI	EA888 evo4	190 PS, chain-driven, Haldex
40 TFSI e / 45 TFSI e	1.4 TFSI PHEV	EA211 + e-motor	204 / 245 PS, high-voltage system
30 TDI	2.0 TDI	EA288 evo	116 PS, twin-dosing SCR
35 TDI	2.0 TDI	EA288 evo	150 PS, twin-dosing SCR

As on the 8V, the timing question splits the range cleanly. The EA211 evo petrols and the EA288 evo diesels are belt-driven with a defined replacement interval. Only the EA888 evo4 in the 40 TFSI uses a chain.

The 48-volt mild hybrid system

Several 8Y petrol variants run a 48V belt-driven alternator-starter (BAS) with a separate lithium-ion battery and a DC/DC converter feeding the conventional 12V system.

This is not a high-voltage system in the traction sense, but it is not a normal alternator either. It restarts the engine while coasting, it recuperates under braking, and the belt is under load in both directions. The documentation covers the BAS unit, the 48V battery, the converter, the correct de-energisation sequence before working on the belt drive, and the fault codes specific to the system.

Transmissions

Six-speed manual — clutch, dual-mass flywheel, linkage and fluid specification.

DQ200 seven-speed S tronic (dry clutch) — the smaller petrol engines. Mechatronic diagnosis, clutch adaptation and basic settings.

DQ381 seven-speed S tronic (wet clutch) — the 40 TFSI quattro and higher-torque variants. Oil and filter service, mechatronic testing.

DQ400e six-speed S tronic — the plug-in hybrid gearbox, with the electric motor integrated into the transmission housing. This is a different unit and it is documented separately.

Shift-by-wire selector — the 8Y has no mechanical linkage between the selector and the gearbox. Selector faults, adaptation and emergency release procedures are covered, because a car that will not come out of Park is not a mechanical problem here.

Haldex all-wheel drive (40 TFSI quattro) — filter and fluid service, pump diagnosis and controller fault tracing.

Driver assistance and calibration

The 8Y carries front radar, a forward camera behind the windscreen, and ultrasonic and side sensors depending on specification.

The camera must be recalibrated after a windscreen replacement, and the radar after any front-end repair or alignment change. Skipping this leaves lane assist and emergency braking working from bad data. The calibration requirements, targets and procedures are covered.

Electrical, diagnostics and infotainment

Full wiring diagrams by model year and body style, connector views and pinouts, CAN, LIN and Ethernet topology, the gateway module, immobiliser and key adaptation, and fault code tables.

Infotainment coverage spans the MIB3 unit and the Virtual Cockpit digital instrument cluster, including the software architecture changes brought by the 2024 facelift.

Known A3 8Y faults this documentation walks you through

• MIB3 infotainment freezes and reboot loops — software-level faults that are commonly misdiagnosed as hardware. Diagnostic route and recovery procedure.
• 48V mild hybrid faults — BAS unit, 48V battery, DC/DC converter. Symptoms range from a warning light to a car that will not restart after a coasting event.
• EA211 evo timing belt — the 1.0 and 1.5 TFSI are belt-driven. Owners of a car this new routinely assume otherwise.
• EA288 evo AdBlue and twin-dosing SCR — dosing pump faults, crystallisation, level sensor errors and forced regeneration.
• DQ200 dry-clutch mechatronic — the same gearbox, and the same failure mode, as the previous generation.
• EA888 evo4 water pump and thermostat module — the long-running weakness of this engine family, carried into the 40 TFSI.
• Shift-by-wire selector faults — the car will not leave Park, or refuses a gear. Adaptation and the mechanical emergency release.
• PHEV high-voltage faults — battery isolation and the de-energisation sequence that must be completed before any work near the orange cabling.
• Camera and radar calibration after glass or front-end work — required, and frequently skipped.
• Electric parking brake — service-mode retraction before rear pad replacement. Force the caliper back without it and you will damage the motor.

Format and delivery

Supplied as a set of searchable PDF files covering the A3 Sportback and Saloon, pre-facelift and the 2024 facelift. Readable and printable on any device: laptop, tablet, phone, or the workshop PC. No software to install, and no internet connection needed once the files are saved.

Select your year at checkout. After payment, your download link is sent within 24 hours.

Frequently asked questions

Does this include the S3 or RS3?

No. The S3 and RS3 are different cars — different engines, different gearboxes, different drivetrains — and they have their own dedicated manual sets. This covers the standard A3 range: 30 TFSI, 35 TFSI, 40 TFSI quattro, the TFSI e plug-in hybrids, and the 30 and 35 TDI. Links to the S3 and RS3 sets are below.

Does my A3 have a timing belt or a chain?

If it is a 30 TFSI, 35 TFSI, TFSI e or any TDI, it is belt-driven with a service interval. Only the 40 TFSI quattro’s EA888 evo4 uses a chain.

Is the 48-volt mild hybrid system covered?

Yes — the belt-driven alternator-starter, the 48V lithium-ion battery, the DC/DC converter, and the de-energisation sequence required before working on the belt drive.

Is the plug-in hybrid (40 TFSI e / 45 TFSI e) included?

Yes, including high-voltage safety procedures, battery isolation and the DQ400e hybrid gearbox. Do not attempt high-voltage work without correct training and PPE.

I replaced the windscreen and now lane assist is behaving strangely. Is that in here?

Yes. The forward camera sits behind the glass and must be recalibrated after replacement. The procedure, targets and requirements are documented. This is not optional — an uncalibrated camera feeds bad data to emergency braking.

Does it cover the 2024 facelift?

Yes. Both the original 2020 cars and the facelifted 2024-onward models are included, along with the infotainment and driver-assistance changes.

Will this work with VCDS or ODIS?

Yes. Fault codes, measuring blocks and adaptation channels map directly to both.

Other Audi A3 generations

• Audi A3 8V (2013–2019)
• Audi A3 8P (2003–2012)
• Audi A3 8L (1996–2003)