2022 Audi e-tron GT SSP 684: Technical Overview

This self-study program (SSP 684) offers an in-depth technical overview of the 2022 Audi e-tron GT (type F8), a fully electric, high-performance Gran Turismo. This document serves as a foundational reference for technicians, detailing the innovative design and functionality of various vehicle systems. It covers everything from the body structure and electric drive to advanced driver assistance systems and thermal management, providing crucial insights into the engineering behind the Audi e-tron GT SSP 684.

Introduction to the Audi e-tron GT

The Audi e-tron GT is designed as a high-performance electric vehicle, combining sporty aesthetics with daily practicality. It features a 100% electric quattro drive, torque vectoring, and four-wheel steering for dynamic handling and grip. High-power charging at up to 270 kW with an 800-Volt electrical system allows for rapid charging, adding approximately 60 miles (100 km) of range in about five minutes. The vehicle is the first Audi Battery Electric Vehicle (BEV) with a flat-floor architecture, contributing to a low center of gravity and enhanced aerodynamics.

Product Highlights

Key features include sophisticated active aerodynamics with controllable air inlets and a variable rear spoiler, optimizing drag and range. The drive system utilizes permanently excited synchronous motors for powerful quattro drive. The optional three-chamber air suspension, two-speed rear transmission, and torque vectoring further enhance both comfort and sporty driving dynamics.

Body Structure and Materials

The Audi e-tron GT (type F8) employs a modern composite construction using various materials to reduce weight while ensuring stringent safety standards. The body structure primarily consists of cold-formed and hot-formed steel panels, aluminum extrusions, and aluminum castings. Aluminum panels are used for the outer skin components, including the front fenders, doors, hood, rear lid, and side panels.

Joining Techniques

Various joining techniques are utilized in the multi-material body, such as resistance spot welding for steel, MIG/MAG welding, laser welding for aluminum, friction element welding, semi-tubular punch riveting, bonding, flow-drill screws, seaming, and clinching.

Underbody Structure and High-Voltage Battery Integration

The high-voltage battery AX2 is fully integrated into the vehicle's floor structure using a battery frame, which enhances body rigidity, particularly in safety-critical areas. An aluminum underbody guard, bolted and bonded to the battery frame, protects the high-voltage battery from damage from below. If the battery frame is damaged, it must be replaced.

Power Units and Drive System

The e-tron GT features permanently excited synchronous motors on both front and rear axles. The power electronics, responsible for converting electric energy, are integrated into the cooling circuit to manage heat. The front axle's power electronics (J1234) can process up to 300 amperes, while the rear axle's (J1235) can handle up to 600 amperes.

Electric Drive Motor Characteristics

Characteristic	Front Axle (EBGA)	Rear Axle (e-tron GT - EBFA)	Rear Axle (RS e-tron GT - EBEA)
Continuous Power Output (at 8000 rpm)	80 kW	120 kW	170 kW
Peak Power Output (at 8000/10000 rpm)	175 kW	320 kW	335 kW
Torque (at up to 5500/5000/5900 rpm for 4 sec)	300 Nm (221 lb-ft)	340 Nm (251 lb-ft)	550 Nm (406 lb-ft)

Electric Drive Cooling System

Coolant flows through the electric drive motors and power electronics, which are integrated into the electric powertrain's coolant circuit. The coolant is first directed to the power electronics to dissipate high heat levels, then flows through the stator cooling jacket. On the rear axle, coolant also passes through the two-speed transmission unit. Only G12evo coolant must be used in the Audi e-tron GT.

Power Transmission

The Audi e-tron GT (type F8) utilizes two types of transmissions: a single-speed transmission (OMG) for the front axle and a two-speed transmission (OME) for the rear axle. The motor control unit J623 regulates drive torque via the power electronics and controls the two-speed transmission OME.

Shift Matrix Overview

The transmission system employs a complex shift matrix involving a dog clutch and a multi-plate clutch to manage gear changes, recuperation, and parking lock functions. For instance, in Drive R (reverse), the dog clutch is engaged, and the multi-plate clutch is disengaged, allowing torque transfer via the sun gear blocked by the dog clutch. In Drive D2 (second gear), both the multi-plate clutch and planetary gear set are blocked, enabling freewheel operation. The system ensures smooth transitions between driving states and recuperation modes, with specific conditions for engaging and disengaging clutches.

Gearbox Warning and Indicator Lamps

Owners should be aware of specific warnings related to the gearbox:

• If the red transmission warning lamp appears in the instrument cluster, the driver is instructed "not to drive any further."
• If the yellow transmission indicator lamp appears in the instrument cluster, it is generally possible to continue driving the vehicle. A corresponding driver message informs the driver of what to do.

Oil Temperature and Clutch Slip Measures

The motor control unit J623 monitors gearbox oil temperature and clutch slip to protect components and ensure proper function. The following measures and messages are triggered based on conditions:

Oil Temperature Measures and Displays

Oil Temperature	Measure	Displays/Messages
> 110 °C (230 °F)	Torque of electric drive motor reduced. Launch control not available.	"Gearbox overheating: please adapt driving style."
> 120 °C (248 °F)	Additionally, forced shift into 2nd gear with downshifting prohibited.	"Gearbox overheating: please adapt driving style."
> 130 °C (266 °F)	Maximum speed reduced additionally.	"Gearbox overheating: please stop vehicle."

Clutch Slip Measures and Displays

Clutch Slip	Measure	Displays/Messages
Sporadic	Torque of electric drive motor reduced.	"Gearbox malfunction: you can continue driving"
Constant	Torque of electric drive motor reduced. Additionally: Forced shift back into 1st gear and therefore reduced maximum speed; upshifting prohibited. No parking lock function.	"Gearbox malfunction: you can continue driving", "Vehicle may roll away! P cannot be selected. Please apply parking brake"

Running Gear and Suspension

The running gear components in the Audi e-tron GT and RS e-tron GT are largely identical, with key differences noted specifically. The vehicle features a steel spring running gear with electronic damping control as standard, with adaptive air suspension available as an option. The four-wheel steering system is an optional feature. Lightweight construction is a priority, with main axle components made of aluminum. The running gear control unit J775 coordinates all running gear systems.

Adaptive Air Suspension

The adaptive air suspension system utilizes air springs with three separate air chambers, allowing for different air spring volumes and spring rates. This enables the suspension to adapt quickly to various driving conditions, from comfortable settings to dynamic, high-speed performance. Four separate sensors detect the acceleration of unsprung masses for increased precision.

Air Spring Volume Features

Volume	Feature
Volume 1 + volume 2 + volume 3	Highest volume, lowest spring rate, most comfortable setting
Volume 1 + volume 2	Medium volume
Volume 1 + volume 3	Small volume, high spring rate, dynamic setting
Volume 1	Smallest volume, highest spring rate, most dynamic setting

Electrics and Electronics

The 2022 Audi e-tron GT introduces a lithium iron phosphate (LiFePO4) battery as its 12-Volt power supply, replacing the traditional lead-acid battery. This battery offers advantages such as lighter weight (approximately 50% less than an AGM battery), increased recuperation capacity, reduced space requirements (20% less volume), and a significantly longer service life (2.5 times longer, 7 times higher cycle stability). The 12V LiFePO4 battery has a nominal voltage of 13.2V and a capacity of 40 Ah.

High-Voltage System

The high-voltage battery AX2 is centrally located and supports the body structure. It consists of 33 battery modules, totaling 396 cells, with a nominal voltage of 726V and an energy content of 93 kWh. The maximum charging capacity is 270 kW. Safety regulations are paramount when working with the high-voltage system, which can be active even when the vehicle is parked and locked. Technicians must always de-energize the system according to test plans and be qualified staff.

Bus Systems Used

The Audi e-tron GT utilizes a variety of bus systems for communication between control units:

Bus System	Method	Data Transfer Rate
Convenience CAN	Electrical bus system	500 kbit/s
Convenience CAN 2	Electrical bus system	500 kbit/s
Extended CAN	Electrical bus system	500 kbit/s
Hybrid CAN	Electrical bus system	500 kbit/s
Dash panel insert CAN	Electrical bus system	500 kbit/s
Infotainment CAN	Electrical bus system	500 kbit/s
Connect CAN	Electrical bus system	500 kbit/s
Diagnostics CAN	Electrical bus system	500 kbit/s
Information electronics 1 CAN	Electrical bus system	500 kbit/s
FlexRay	Electrical bus system	10 Mbit/s
MOST bus	Fibre optic bus system	150 Mbit/s
LIN bus	Electrical single wire bus system	20 kbit/s
Sub-bus systems	Electrical bus system	500 kbit/s
Ethernet	Electrical bus system	100 Mbit/s

Infotainment and Audi Connect

The Audi e-tron GT features the third generation of the modular infotainment matrix (MIB3) system, with MMI navigation plus (7UG) as the standard. Key features include:

• 10.1-inch MMI touch display (1540 x 720 pixels)
• Audi virtual cockpit plus, 12.3-inch (959)
• 3D navigation system on SSD (7UG)
• FM radio, DAB digital radio, and Sirius XM (QV3)
• Connected radio (Internet radio) and HD radio
• Audi smartphone interface (IU1)
• Two rear USB-C sockets (UF8)
• Audi sound system (9VD) and Bluetooth interface (9ZX)
• Audi connect emergency call & service (IW3) and infotainment plus (IT3)

The standard Audi sound system (9VD) includes 10 loudspeakers with a 150 W output. The optional Bang & Olufsen Premium Sound System with 3D sound (9VS) offers 16 loudspeakers and a 710 W output.

Safety and Driver Assistance Systems

The driver assist systems in the Audi e-tron GT are based on the MLBevo2 platform, sharing architecture with models like the Audi A8 (type 4N) and Q7 (type 4M). The central control unit is the driver assist systems control unit J1121 (zFAS). Standard equipment includes cruise control with speed limiter, lane departure warning, parking system plus, pre sense basic, and pre sense front.

Park Assist Plus and Remote Park Assist Plus

The park assist plus system (requiring J1121 version C) provides enhanced parking assistance by taking full control of steering, acceleration, braking, and transmission changes. It uses 12 sixth-generation ultrasonic sensors (G203-G206, G252-G255, G568-G569, G716-G717) and four overhead view cameras (R243-R246) for detailed environmental information. The remote park assist plus extends this functionality, allowing control via a smartphone app from outside the vehicle, particularly useful in tight parking spaces.

Servicing, Inspection & Roadside Assistance

Service intervals are displayed based on mileage and/or time, with the instrument cluster showing remaining days before service is due. The service interval display must be reset using the vehicle diagnostic tester. The Audi e-tron GT SSP 684 also details diagnostic functions available via address words 0001 (Engine electronics J623) and 0032 (Lock electronics J647), covering functions like renewing control units, adapting sensors, and checking configurations.

Important Warnings for Owners

Owners of the 2022 Audi e-tron GT should be aware of several critical warnings detailed in the SSP 684:

• "The high-voltage system of an Audi e-tron GT may be active even though the vehicle is parked and locked." Always exercise caution around the vehicle's high-voltage components.
• "The vehicle cannot be operated if the 12 V LiFePo4 battery is discharged. The Audi e-tron GT must NOT be used to jump-start other vehicles!" This prevents damage to the 12V battery and other vehicle systems.
• "It is not permitted to 'miss out' service events." Adhering to maintenance schedules is crucial for vehicle longevity and safety.
• "The vehicle must not be towed or push-started." Special transport methods are required for the e-tron GT.
• "If the red transmission warning lamp appears in the instrument cluster, the driver is instructed not to drive any further." This indicates a critical issue requiring immediate attention.
• "If the yellow transmission indicator lamp appears in the instrument cluster, it is generally possible to continue driving the vehicle. A corresponding driver message informs the driver of what to do." Pay attention to these messages and follow instructions.
• "Alternating voltage of 25 Volts and above and direct voltage of 60 Volts and above are hazardous to human beings." Always observe safety instructions when dealing with electrical systems.
• "Always de-energise the system according to the test plan in the vehicle diagnostic tester. The high-voltage system must only be de-energised and worked on by qualified staff." High-voltage work requires specialized training and procedures.

---

Source: NHTSA ID: 10190946