Self-Study Program 990303 The 2012 Audi A7 Running Gear and Suspension Systems Audi of America, LLC Service Training Printed in U.S.A. Printed 1/2011 Course Number 990303 ©2010 Audi of America, LLC All rights reserved. Information contained in this manual is based on the latest information available at the time of printing and is subject to the copyright and other intellectual property rights of Audi of America, LLC., its affi liated companies and its licensors. All rights are reserved to make changes at any time without notice. No part of this document may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, nor may these materials be modifi ed or reposted to other sites without the prior expressed written permission of the publisher. All requests for permission to copy and redistribute information should be referred to Audi of America, LLC. Always check Technical Bulletins and the latest electronic repair literature for information that may supersede any information included in this booklet. Table of Contents Introduction . 1 Axles and Wheel Alignment . 2 Overview . 2 Front Axle . 3 Rear Axle . 4 Running Gear / Alignment . 5 Adaptive Air Suspension . .6 Overview . 6 System Components . 7 Control Strategy . 12 Operation and Driver Information . 14 Service Work . 15 Steering System . .19 Overview . 19 Electromechanical Steering . .20 Overview . 20 System Components . 21 Operation and Driver Information . 29 Service / Diagnosis Functions . 30 i Table of Contents Brake System . .32 Overview . 32 System Components . 33 Service Work . 34 ESP . .35 Overview . 35 System Components . 35 Operation and Driver Information . 37 Service Work . 38 Sensor Electronics Control Module J849 . .39 Overview . 39 Adaptive Cruise Control (ACC) . .41 Overview . 41 Tire Pressure Monitoring (TPMS) . .43 Overview . 43 Self-Study Programs for the 2012 Audi A7 . .44 Knowledge Assessment . .45 The Self-Study Program provides introductory information regarding the design Reference Note and function of new models, automotive components, or technologies. The Self-Study Program is not a Repair Manual! All values given are intended as a guideline only. ! For maintenance and repair work, always refer to current technical literature. ii Introduction The major development goals for the running As in other Audi models, the steering gear is gear and suspension of the 2012 Audi A7 were mounted forward of the front axle which helps to achieve great agility, precise handling, a high ensure exact steering response and a precise level of safety, and refi ned driving comfort. steering feel in every driving situation. These goals have been accomplished with The implementation of electromechanical power the use of Audi’s proven fi ve-link front axle in steering has not only reduced fuel consumption conjunction with a trapezoidal link rear axle. This but also enabled additional functions that is the same suspension confi guration used on contribute to driver safety. the 2011 Audi A8. Other design features, such as mounting the front fi nal drive ahead of the differential, resulted in a larger wheelbase, which increased ride comfort and shortened the front overhang. 480_001 1 Axles and Wheel Alignment Overview The following running gear and suspension variants are available for the 2012 A7 in North America: Production Technical Control Description Offer Implementation Number (PR) 1BA Standard running gear /suspension Steel suspension Series standard 1BE Sports running gear /suspension Steel suspension Option Sports running gear /suspension 1BV Steel suspension Option S line (offered from quattro GmbH) Adaptive air suspension 1BK Air suspension Option (delayed introduction) 480_002 2 Front Axle As stated earlier, the design of the front axle was In addition to reducing weight and increasing based on the fi ve-link front axle used in the 2011 rigidity, this has also meant that the installation A8. The bearing bracket to support the upper tolerances of the upper axle link have been axle link has also been integrated into the body reduced. As a result, the stabilizers and shock of the A7. absorbers were then reconfi gured. Newly developed upper axle link Shock absorber forks adopted from 2011 A8 Newly developed guide link Newly developed swivel bearings Connecting link adopted from 2011 A8 Shock absorbers – Newly developed – With regulated damping on vehicles with Adaptive Air Suspension Newly developed Wheel bearings anti-roll bar adopted from 2010 A4 Newly developed subframe Support link Wheel hub adopted 480_003 adopted from from 2010 A4 2010 A4 Joint adopted from 2010 A4 3 Rear Axle The rear axle is based on the trapezoidal link This design increases pass through loading rear axle already used in the Audi Q5 quattro. capability when the fl oor is level. The springs and shock absorbers are arranged separately from one another. Wheel carrier – Newly developed – Adopted from Q5 quattro – Cast aluminum forged part Anti-roll bar – Newly developed – Steel tube Connecting link – Adopted from Audi Q5 Upper wishbone – Adopted from Q5 quattro and 2011 A8 Steel springs – Aluminum forged part – Adopted from Audi Q5 quattro Shock absorbers – Newly developed – With regulated damping on vehicles with Adaptive Air Suspension Subframe – Newly developed Wheel bearings – Steel construction – Adopted from – Rear bearing hydraulic Audi Q5 quattro – Front bearing conventional Trapezoidal link Wheel hub – Forged steel part 480_004 – Adopted from – Forged steel part – Adopted from Audi Q5 quattro Track link Audi Q5 quattro – Newly developed – Steel part for vehicles with steel suspension – Forged part for vehicles with Adaptive Air Suspension 4 Running Gear / Alignment The alignment of the front and rear axles is the same as on the 2011 A8. The adjustment points are identical for steel suspension vehicles and those with Adaptive Air Suspension. Camber adjustment at connection point wheel carrier — upper wishbone Toe adjustment at connection point 480_005 subframe — track link Camber balancing subframeby shifting to the the side Toe adjustment at the track rods 5 Adaptive Air Suspension Overview The design and operation of the Adaptive Air Suspension system of the Audi A7 are the same as those of the 2011 A8. However, Adaptive Air Suspension will not be available at vehicle launch. Left Front Damping Adjustment Valve N336 Left Front Level Control System Sensor G78 Right Front Damping Adjustment Valve N337 Left Rear Damping Adjustment Valve N338 Sensor Electronics Control Module J849 Left Rear Level Control System Sensor G76 Air springs Solenoid valve block Right Front Level Control Sensor G289 Right Rear Damping 480_006 Adjustment Valve N339 Pressure accumulator Air supply system with compressor Level Control System Control Module J197 Right Rear Level Control System Sensor G77 6 System Components Level Control System Control Module J197 Solenoid Valve Block J197 communicates over the FlexRay data bus. The design of the solenoid block and its electric It receives relevant acceleration signals from and pneumatic functions is identical to the 2011 Sensor Electronics Control Module J849. Audi A8. The connection assignment and color coding of the lines are identical, too. J197 actuates the solenoid valves and air compressor for leveling the vehicle and However, the solenoid valve block differs from adjusting the dampers. Damper valves are only the 2011 A8, in that it is not part of the air operated while the vehicle is being driven and supply unit. Instead, it is located separately in a road speed signal is being received from ABS a recess of the foam cover above the pressure Control Module J104. accumulator. Actuating current to the dampers is in a range of When removing the vehicle battery, the solenoid approximately 0.0A to 1.8A. Maximum damping block can be moved from its position together force is achieved at approximately 0.0A, while a with the foam cover without removing the air current of 1.8A is required for minimum damping lines. force. To achieve the greatest possible driving comfort, the base current applied to the valves is approximately 1.8A. If the driver has selected dynamic mode, the greatest comfort is achieved when 1.6A current is applied. J197 is located in the right rear of the luggage compartment, behind the trim panel. 480_008 480_007 7 Air Supply System The air supply system consists of the dry A single stage compressor generates up to running, electric motor driven compressor, an 261.0 psi (18 bar) pressure to operate the system. air dryer, intake dampers, and corresponding A pressure limiting valve in the compressor air lines. The air supply system unit is installed protects the system from over pressure. Air is under the spare tire well. Its components are drawn in via intake dampers and the air dryer attached to a steel plate bracket by springs and from the left rear wheel housing. The air dryer is rubber mounts. self-regenerating and requires no maintenance. The complete unit is attached to the vehicle body To protect against mechanical damage from with rubber/metal mounts. These mounts help overheating, the compressor temperature is insulate the body acoustically from the unit. An “model calculated” by measuring the change of outer cover with stone chip protective material is resistance in the magnetic coil of the drain valve. bolted onto the bracket. Air intake Steel plate Electric motor bracket Bonded rubber metal mounts Air dryer Compressor 480_009 Bonded rubber metal mounts Rubber mounts 8 Pressure Accumulator The task of the pressure accumulator is to The volume of the accumulator is 1.5 gal maintain system availability. When the vehicle is (5.8 liters). Air lines from the pressure stationary or moving at slow speeds, all control accumulator to the solenoid valve block, as pressure changes are carried out through the well as from the compressor to the solenoid accumulator if there is suffi cient pressure. block, have large cross sections which allow the This means that it is not necessary to run the accumulator to fi ll quickly.