Audi A6 Allroad technical specifications. Audi Allroad (C5) - model description. Signal from door switches

A large and prestigious station wagon – this is exactly how the Audi Allroad was positioned. But the main emphasis was not even on this, but on the “zest” in the form of an adjustable ground clearance. But how did the famous air suspension perform? Let's find out, and at the same time talk about the other components and assemblies of this car. And is it worth choosing this car?

There are no complaints about the body. It is remarkably protected from corrosion. There are none for the salon either. Naturally, on a car of this class, all materials used in the interior are of the highest quality. Even in winter you won’t hear any squeaks from their performance. But complaints sometimes arise regarding the operation of numerous electronic systems. So when purchasing, don’t be lazy to check the operation of the air conditioner, power windows, windshield wipers, and radio. The same air conditioning clutch is quite expensive. And it would seem a trifle.

All engines installed on the Audi Allroad are quite reliable, although without the characteristic weak points it still didn't work out. In any engine, periodically check the oil level, since its consumption increases with increasing mileage. And if you don’t do this, then very soon the hydraulic compensators will start knocking. By itself, one hydraulic compensator is not that expensive, but the problem is that even in a six-cylinder engine there are a lot of them. As a result, replacement will cost a decent amount. Adding a liter of oil will be much cheaper. And don’t forget that you need to refuel only with high-quality fuel. Also, before purchasing, make a diagnosis of the turbines that are installed on a 2.7-liter engine. Replacing them will greatly undermine the family budget. The maintenance of gasoline engines itself will come down to changing the oil and spark plugs. It is better to change the oil every 10 thousand kilometers, and the spark plugs will last about 35 thousand kilometers. Plus the replacement of the timing belt, drive belt, rollers and pump, which will be necessary for those owners who drive a car with a 2.7-liter engine. This replacement will occur at the 100 thousand kilometer mark. It would be great if it was done before you, since all this will cost a decent amount. But the 4.2-liter engine uses a metal chain. There is no need to change it, but in this case there is no question of saving. This engine is too power hungry. You will have to refuel frequently.

The 2.5 liter diesel engine is good in its own right. But on our diesel fuel, the fuel pump does not last long. Yes, and the turbine, although quite reliable, can still fail. And these units cost a lot. So diagnosing a car with a diesel engine should be a prerequisite for purchase.

But with the gearbox, no matter what, there will be fewer problems. In the “mechanics”, after a mileage of 150 thousand kilometers, you will have to change the clutch. Automatic transmission It is also quite reliable, but be aware that its repair is expensive. So buying a “killed” car with your last money is fraught with danger. System all-wheel drive, if you don’t drive every day on serious off-road conditions, it’s quite reliable.

Well, now the most important thing - the air suspension. If it suddenly stops functioning, then immediately check the wires going to the compressor. Usually it's them. Don't rush to change the compressor itself. Also try to periodically wash the car from dirt. Body position sensors don't like it. But in any case, after a run of 180 thousand kilometers you will have to change the suspension cylinders. If we talk about the mechanical components of the suspension, then every 70 thousand kilometers you will have to change the levers in the front suspension. And after a run of 100 thousand kilometers, shock absorbers and wheel bearings may require replacement. But there are far fewer problems with the rear suspension. If something has to be changed relatively often, it will only be the silent blocks.

The steering linkage will have to be replaced. Fortunately, they can withstand more than 120 thousand kilometers.

In the braking system, the front brake pads need to be replaced every 30 thousand. The rear pads can withstand twice as much. Brake discs have approximately the same service life.

It turns out that the air suspension is quite reliable. But in any case, you shouldn’t have your head in the clouds with this car. It was originally intended for wealthy people, so even in a used state you can’t expect small expenses for its maintenance and repairs. You'll have to pay. But if you want to reduce your costs at least a little, then try to choose a car where the main work on replacing worn-out components was carried out by the former owner. Or feel free to bargain.

General information about the model

The first generation Audi Allroad (C5) is a premium all-wheel drive station wagon. The all-terrain vehicle is a 5-door modification of the Audi A6 Avant with permanent all-wheel drive. The Allroad C5 was assembled at the company's plant in Germany. The first generation of the model was produced from 1999 to 2005.

German automobile concern Audi has long been famous for its all-wheel drive vehicles, but until 1998 they remained just city cars with good handling. However, German engineers, spurred on by their competitors, primarily the Japanese, decided to gain fame in the class of “all-terrain” cars. Thus, the flagship of the Audi A6 Avant line was modernized, and the first SUV from Audi, the Allroad C5, saw the light of day.

The car was first shown in 1998 at the Detroit Motor Show. By the end of the 90s, interest in such hybrids of an SUV and passenger car especially increased, primarily in the USA, which explains the choice of presentation location. Having received the most flattering comments from the public, German engineers polished the prototype and in 1999 the first production samples of the Audi Allroad C5 rolled off the assembly line.

Undoubtedly, the developers of the new model did not ignore the successes of Japanese competitors in this field, so in many ways the Allroad resembles Subaru Outback. But they took only the concept as a basis - a passenger all-terrain vehicle, or simply an SUV.

Interestingly, the C5 was produced unchanged until the release of the second generation Allroad. Compared to its predecessor Avant, the Allroad is 15 mm longer, half a centimeter wider and 140 mm higher. In terms of design, the Audi Allroad C5 retains the features of a premium car, but a number of elements, such as large wheel arches, wheels and aluminum trim on the doors and radiator grille, add some sportiness and aggressiveness to the appearance.

In 2005, it was replaced by a second generation model, the C6. However, along with the updated Allroad, the C5 is still quite popular today.

Technical features

Audi Allroad C5 cars were equipped with the following engines: six-cylinder gasoline engines volumes of 2.7 and 4.2 liters, and diesel 2.5 liters. Increased power was achieved thanks to five valves for each of the six cylinders and an injection system with modified manifold geometry. Despite the fact that the engine is configured primarily for high torque, acceleration and maximum speed also decent - less than 8 seconds to 100 km/h very good result for a massive station wagon.

Perhaps the main advantage of the Audi Allroad is electronic system suspension settings. The car driver can choose 4 driving modes. For each mode, ground clearance is provided in the range from 142 to 208 mm. It is important to note that if the driver chose the wrong mode, or simply forgot to switch it after driving off-road onto a flat surface, the electronic control unit will automatically change the suspension settings based on data from numerous sensors. A similar idea became widespread on sport-touring motorcycles in 2008, while Audi has been using it since 1998.

Since the Germans had encroached on the off-road elements, it was impossible to do without a series of low gears. The Audi Allroad C5 was equipped with a so-called range multiplier, which can be turned on using a button on the gearbox selector. The speed of movement in this mode is limited to 70 km/h, but it is very difficult to imagine a madman who would want to drive through the forest at a higher speed, and even in a premium car.

The well-known company Pirelli has produced special tires for the Allroad C5. On the side of the tire there is the inscription “Allroad”, and the tread of the wheel is slightly deeper than the universal “rubber” from Pirelli.

Audi Allroad is one of the first models that gave birth to a new class of cars - SUV.

The sliding sunroof of the car in the luxury version is equipped with a solar battery, the charge of which is sufficient to operate the cooling system.

Competitive advantages

The main competitors of the Audi Allroad C5 are Subaru Outback and BMW X5. The competitors are very serious, but Audi can compete with dignity even with them.

What primarily distinguishes SUVs from SUVs is fuel consumption. Audi cannot have SUVs among its competitors, for obvious reasons, but in comparison with Subaru and BMW, the Allroad C5's efficiency indicators are an order of magnitude higher. When driving outside the city and in mixed mode, Audi's fuel consumption is 7% lower.

The maximum speed indicator is beyond competition - the Allroad C5 2.6 liter petrol engine allows the car to reach speeds of up to 234 km/h, while the X5 and Subaru Outback limit does not exceed 220 km/h.

Audi's main trump card is the Allroad C5's very decent off-road qualities. An important role here was played by air suspension with the ability to adjust ground clearance. But we should not forget that one of the the most important indicators for cars like the X5 and Allroad, is the level of comfort.

Awards

According to the results of the EuroNCAP crash test, the Audi Allroad C5 received three stars for the safety of adult passengers.

In 2001, the Allroad C5 entered the top 10 best cars of the Year according to the American magazine Car and Driver.

Audi Allroad is an all-wheel drive all-terrain station wagon.

In February 2000, at the Geneva Motor Show, the first model of Audi's all-terrain vehicle was presented for the first time, which was designed to compete with such models as the Subaru Legacy Qutback, Volvo V70XC and others, including the BMW X5 and Mercedes ML. The Allroad SUV model is made on the improved Audi A6 Avant platform.

Most interesting feature New is the active air suspension. The automation itself monitors the condition of the road surface and accordingly changes the vehicle’s ground clearance (depending on the speed of movement, this change occurs in steps: at a speed of more than 120 km/h it will be 142 mm, in the range from 80 to 120 km/h the clearance will be 167 mm, at speeds below 80 km/h the ground clearance will increase to 192 mm, the maximum ground clearance of 208 mm will be selected for driving with low speed on a bad road). And also the four-level ALLROAD air suspension allows the driver himself, by pressing the corresponding button on the instrument panel and observing the behavior of the car on the display screen, to select different ride heights, increasing it from 142 to 208 mm. For comparison, the BMW X5 has a clearance of 180 mm, and the Mercedes ML has 200 mm, and even the latest model Range Rover exceeds this figure by only 2 mm. At the same time, with the help of electronics, the Allroad maintains a specific ground clearance regardless of the load on each wheel, i.e. depending on the number of passengers and the amount of cargo in the car, and thanks to diaphragm pneumatic elements, the car’s ride is ensured with high smoothness. To increase traffic safety with ground clearance values of 192 and 208 mm, the automatically activated body position stabilization system will prevent dangerous rolls when turning and longitudinal tilts during sudden braking. The suspensions are assembled on subframes, which are attached to the body through rubber-metal supports.

In general, the exterior design is similar to that of the five-door Audi A6 station wagon. Comparing the dimensions, we note that the Allroad is 14 mm longer, 42 mm wider and 138 mm taller than the A6 Avant quattro model with a 67 mm longer wheelbase. The body is decorated with polished metal: linings on the lower edges of the doors and panels at the bottom of the bumpers, protecting the plastic from impacts. Arches are made in VW style Golf first and second generations. Wide tires, wheel arch extensions and beefier bumpers with a three-piece grille and fog lights give the Allroad a more solid and imposing appearance. Aggressive protection of the crankcase and rear axle made of corrugated stainless steel, specially exposed to public display, as well as aluminum door sills leave no chance for those who doubt the off-road purpose of the car.

The interior is also similar to the design of the Audi A6, the difference lies in the color scheme of the interior. The control panel is trimmed with plastic, the instruments are equipped with polished rims. Inside, the driver and passengers will feel just as comfortable as in the standard A6. According to the creators of the Allroad quattro, five people will feel quite comfortable even on a long journey.

Of course, the car has permanent drive all wheels with a central center differential of the Torsen type (the inter-axle differential locking is simulated by braking the slipping wheels), disc brakes with ABS and dynamic motion stabilization system EPS. The latter is quite appropriate on a car whose maximum speed even with diesel engine exceeds 200 km/h. Allroad received an additional reduction range of gears in the transmission, which significantly increases its traction characteristics in heavy conditions. road conditions. Of course, the Allroad Quattro's element is good roads, and not country roads at all. However, if necessary, the car can tow a trailer gross weight up to 2300 kg and move confidently on dirt roads.

The Audi Allroad is available with two types of engines: a petrol 2.7-liter V6-Biturbo with 250 hp, equipped with two turbochargers, and a 2.5-liter V6-TDi turbodiesel with direct injection, developing 180 hp. Transmission options include a 5-speed automatic Tiptronic and a 6-speed manual, which can optionally be supplied with a selectable reduction gear "LOW RANGE". It can be engaged at speeds of up to 30 km/h and used for driving at speeds of up to 50 km /h. Result: more freedom when driving in difficult terrain. With a 250 hp engine, the car reaches speeds of up to 236 km/h and accelerates from zero to 100 km/h in 7.4 seconds. Allroad will also receive a gasoline V8.

Equipped with such advanced components and systems, the Audi Allroad Quattro is able to take its rightful place among all-wheel drive vehicles in the rapidly growing European SUV market. Allroad is expected to be produced in quantities of up to 20 thousand per year, which should increase the share of all-wheel drive vehicles produced by the company to 30%.

On Russian market The “third” all-terrain station wagon, the Audi A6 allroad quattro, was released in April 2012 and has since firmly held a leading position in its segment, offering owners not only a high level of comfort, but also excellent crossover-level cross-country ability. This year (September 2014) the Audi A6 allroad quattro station wagon underwent a planned update, becoming more attractive in appearance and more powerful technically.

The appearance of the Audi A6 Allroad Quattro “in the C7 body” is built on the basis of the Audi A6 Avant, but the off-road station wagon received a characteristic plastic body kit (sill plates, wings), bumper protection, a different radiator grille and a slightly adjusted front bumper. All this splendor has been neatly transformed as part of the current restyling, making the exterior even more brutal and attractive. The length of the Audi A6 allroad quattro station wagon is 4940 mm, width – 1898 mm, and height – 1452 mm. The wheelbase is 2905 mm, which is 7 mm less than the Audi A6 Avant. Curb weight of the A6 allroad quattro is 1855 kg.

The 5-seater interior of the A6 allroad quattro offers comfort at a level passenger car business class, for which many appreciate the station wagon, which compares favorably with crossovers in this regard.

The interior design of the A6 allroad quattro is practically no different from the Audi A6 sedans and the A6 Avant station wagon, but the list of basic equipment is noticeably wider. The trunk holds 565 liters in the base and 1680 liters with the second row of seats folded.

Technical specifications. Before restyling, the Audi A6 allroad quattro all-terrain station wagon was equipped with two options power plant: diesel V6 with turbocharging and direct injection, developing 245 hp, or petrol V6 with compressor and direct injection, capable of delivering 310 hp. power.
After restyling, there are also two engines left. The diesel engine migrated to the updated station wagon without changes, but the power of the gasoline engine increased to 333 hp. (same as Audi A6 sedan).
Both engines, as before restyling, are combined with a 7-speed S-Tronic dual-clutch automatic transmission.

The Audi A6 allroad quattro already comes standard with a fully independent adaptive air suspension with adjustable ground clearance (ground clearance varies in the range of 135–185 mm), as well as a permanent all-wheel drive system based on a central self-locking center differential and a traction vector control system on the rear axle. All wheels of the station wagon are equipped with ventilated disc brakes, parking brake The Audi A6 allroad quattro has electric drive. The car's rack and pinion steering mechanism is complemented by an electromechanical amplifier with a variable transmission ratio. The Audi A6 allroad quattro base is equipped with ABS systems, EBD, BAS, ESP, ASR and hill start assist system.

Equipment and prices. The Audi A6 allroad quattro has a list of basic equipment similar to the A6 Avant station wagon, but additionally receives 18-inch alloy wheels, bi-xenon optics, leather upholstery, more expensive interior design, heat-insulating glass tinting and other features. The cost of pre-restyling cars starts at 2,630,000 rubles. After restyling, the cost of the Audi A6 allroad Quattro will be 2,645,000 rubles for the version with a 245-horsepower diesel engine and 2,775,000 rubles for the modification with a 333-horsepower gasoline engine. The updated station wagons will appear at dealers at the end of October 2014.

The four-level air suspension of the Audi Allroad Quattro is a logical development of the self-levelling system implemented in the Audi A6.

Introduction

Designing a car ideal for good conditions traffic and off-road – sounds like squaring a circle. Usually good SUVs They have not very pleasant driving characteristics for daily use on good roads. The high ground clearance – a decisive advantage on off-road terrain – determines the vehicle's high center of gravity.

However, this comes at a disadvantage when it comes to fast cornering or stability at high speeds. In addition, a high body position means greater air resistance and increased consumption fuel.

On the contrary, the shorter the suspension travel, the better car"holds the way." However, this same quality significantly worsens off-road performance. Variable ground clearance is the optimal solution for operating a car on any type of road - this design solution is called 4-level air suspension.

The air suspension in the Allroad Quattro model is based on the “family” system from the Audi A6.

System Description

The 4-level air suspension includes full body level control with conventional spring dampers on the front axle and load-sensing dampers (PDC) on the rear axle. The height of the car body is controlled individually for each side - using four level sensors.

Each suspension mount contains a gas-filled “spring” and a so-called “cross valve”. In this way, each axis can be controlled individually.

The 4-level air suspension is designed as a system based on an air accumulator. This design improves performance characteristics system, reduces noise levels and increases compressor protection.

One of the features of the suspension is the ability to change the vehicle's ground clearance by 66 mm in 4 stages. All four stages can be controlled manually or automatically.

Body position levels are indicated as follows:

Level 1 = Low Level (LL)
Level 2 = normal level (NL)
Level 3 = High Level 1 (HL1)
Level 4 = High Level 2 (HL2)
Parking PL = high level 1

The latest fully controlled air suspension design was developed specifically for the Audi Allroad Quattro. In addition to the advantage of automatic control and maintaining the body level above the road, as described for the Audi A6, this suspension system has additional advantages:

The 4-level air suspension contains sophisticated electronically controlled suspension components on both axles. The system allows you to change the body level by 66 mm and offers four options for ground clearance (from 142 to 208 mm);
Depending on road conditions and personal preference, you can choose a higher ground clearance or a lower vehicle position for improved handling and reduced drag;
4-level air suspension automatically maintains a constant body level regardless of the load and weight distribution inside the body;
Setting any of the 4 levels of ground clearance can be done manually or automatically within specified limits;
Individual automatic functions or the system as a whole can be disabled using the control unit;
The LED indication on the control panel clearly informs about the current operating mode of the suspension;
The pneumatic accumulator system ensures maximum driving comfort.

Operation

The E281 automatic level control unit is used to control the 4-level air suspension and monitor/alarm the system status. Changes of a certain level occur automatically during normal driving. Depending on road conditions, the driver can use the "Raise" or "Lower" buttons to force the appropriate ride height at any time.

Pressing the Raise button once immediately switches the suspension to the next higher level. By pressing again, you can “jump” through the levels - for example, from “Low Level” directly to “High Level 1”. However, "High level 2" cannot be selected immediately - only if the suspension is already at level "High 1".

The transition to low levels is performed in the same way - using the “Lower” key. When pressed multiple times, you can go directly from the “High 2” level to the lowest level.

Please note:

the body can be raised to a higher level only when the engine is running or when there is sufficient air pressure in the pneumatic accumulator;

The body height can be reduced even when the engine is not running.

Indication

One of the control panel's four LED indicators, which are located one on top of the other, lights up continuously to indicate the current suspension level.

Only the level change procedure (automatic or manual) will cause one or more LEDs to blink. After the suspension moves to new level, the indicators will stop flashing and return to steady light.

LEDs inside the Raise and Lower keys indicate command execution and verification. If the LED flashes, the command to change the suspension level has been rejected (for example, if the driving speed is too high).

If the actual suspension level deviates significantly from the optimal level, the corresponding diodes will flash, “telling” the driver best option level adjustments.

“Significant deviations” mean:

when at least one axle is lower than the next lowest suspension level relative to the current value;
both axles are higher than the next highest suspension level.

Purpose of other keys

Each of the buttons has its own purpose, let’s look at what each of them is needed for.

Automatic switching

The so-called " manual mode» can be turned on or off by pressing the “Raise” or “Lower” keys (must be held for at least 3 seconds). A yellow indicator labeled “man” indicates to the driver that the suspension is in manual mode. "Parking level control" and "Motorway mode" are disabled in manual mode.

Switching off the control system

The control system is turned on or off by pressing the “Level” button (you must hold it for more than 5 seconds). When the control system is switched off, the operating unit LEDs for manual mode as well as both level buttons and indicator light K134 are activated. Level indicator LEDs show the current level. The corresponding indicator lights up continuously.

The control system, which has been switched off, is activated automatically when the vehicle speed exceeds 10 km/h (unless the “lifting platform” mode is recognized). The control system can also be disabled using diagnostic testers.

Control algorithm

There are two types of control units (depending on the country of import of the car). The control algorithms described below apply to the control unit 907 4Z7 553A. The differences in the operating parameters of control units with numbers 4Z7 907 553B are described below.

If the vehicle is in the highest off-road “Level 2”, it will automatically “squat” to “Level 1” at speeds greater than 35 km/h. The control system will only allow an increase to “Level 2” at speeds below 30 km/h.

If the car's suspension is at "Level 1", then at a speed above 80 km/h the control system will automatically lower the body to a normal level. The system will respond to a manual command to raise the body to “Level 1” only if the speed is less than 75 km/h.

While driving, automatic transition to off-road “Level 1” and “Level 2” is not available. This command must be manually selected by the driver. The "Parking" level is an exception. This mode automatically raises the vehicle to off-road "Level 1" when stopped and locked.

Motorway mode

If the car moves faster than 120 km/h for more than 30 seconds and the suspension is at the “Normal” level, then the body will automatically lower down to the “Highway” mode. This reduces air resistance to save fuel and lowers the vehicle's center of gravity, improving handling.

The car body automatically rises to normal level in the following modes:

Algorithm of the “Parking” mode

The “Parking” mode ensures that the vehicle remains at the same height after stopping for a long time. A decrease in level is possible only due to cooling of the air in the air cylinders or natural diffusion of the working fluid. The mode makes it easier to enter/exit passengers and load luggage, and also improves appearance motionless vehicle. Parking level corresponds high level suspensions - “Level 1” (HL1).

The “Parking” mode is activated:

when the system is in standby mode and the car is locked from the outside;
when there is sufficient air pressure in the pneumatic accumulator;
when the system is not in manual mode.

Please note: Parking mode (PL=HL1) is only canceled when the speed reaches 80 km/h or when manually switching to a lower level.

If the suspension is already in Level 2 (HL2) off-road mode, the body will not lower to Park.

Manual mode

The “Highway” and “Parking” levels are available in the manual suspension mode.

The differences from the 4Z7 907 553A device described above are:

lack of parking level control;
automatic level upgrade to HL

Conditions for automatically raising the body to “Level 1” (HL1):

the system should not be in manual mode;
Between turning the ignition on and off during the current trip, the driver must select the “Level 1” or “Level 2” suspension mode at least once.

The vehicle body automatically rises to “Level 1” under the following conditions:

If the system has reduced the body height to the minimum level (Motorway mode), the suspension will automatically rise to Level 1 when the speed drops below 60 km/h after 30 seconds of driving.

Safe automatic shutdown of the ESP system

For technical reasons, it is not possible to change the level/position of the body when cornering. If cornering is detected, the suspension control functions are disabled. However, control commands are stored in memory and implemented as soon as the car begins to move in a straight line.

In the Audi Allroad Quattro, you can influence the algorithm of the ESP stabilization system using the “ESP” button of the same name on the suspension control unit. If the ESP operation has been changed by pressing the "ESP" button when the LED indicator ESP, skid dynamics control, switches to passive mode, but not during braking.

If, for example, the car's suspension is in "Level 2" mode with ESP activated and the driver accelerates sharply on a very winding road, speeds in excess of 35 km/h can be achieved even at this suspension level. To guarantee maximum safety in these driving conditions, ESP is automatically switched off at speeds above 70 km/h, despite a high center of gravity. This is called “safe automatic shutdown “ESP”.

Normal ESP functions will be available again and the ESP lamp will go out. “Safe auto switch-off” of ESP occurs at 70 km/h for the “Level 2” suspension mode and at 120 km/h for “Level 1”. For normal or low level There is no “safe auto-shutdown” ESP suspension.

Please note: turns are detected by the self-levelling control unit J197 by evaluating the signals from four body level sensors.

System components

Let's take a closer look at each component of the Audi Allroad Quattro air suspension.

Pneumatic supports

The front suspension struts feature a completely new design. As on the rear axle, the pneumatic elastic elements are installed coaxially with the shock absorbers in the form of a single suspension strut. The rear air mounts are identical in design and function to the units used on the Audi A6 suspension (also equipped with a self-leveling function).

Design

Same as for rear pillar, the connection with the simultaneous sealing of the air support (piston) with the shock absorber is made using a double bayonet seal (for the front strut it is made as a single sealing connector No. 17). Differences in design required a change in the type of unit.

Front suspension strut

The front air support is connected to the shock absorber without lubrication. During installation, connector No. 17 and the sealing ring must be absolutely dry and free of grease. Before assembling the air mount, make sure that the O-ring is on the second shoulder of the shock absorber and is pressed evenly over the entire surface. The pneumatic support (piston) is installed on the shock absorber and pressed in by hand. The O-ring is pulled onto collar 3 as the piston moves, where it is held and seals the pneumatic support.

Rear suspension strut

Before installation, the connecting units must be cleaned and lubricated with special lubricant. To install, the air support is pushed out and rotated slightly.

Operating air pressure in pneumatic supports

Please note: O-rings should always be checked for leaks. The surface must be clean, free from rust and pitting (for aluminum parts). You should also lubricate the rings as needed.

Attention! Do not touch the piston when installing or transporting the suspension strut assembly, as the piston can be easily damaged if there is no internal air pressure. If the O-ring is pushed out of the air support, it means that the seal of the strut is broken.

The air mounts must not be compressed without operating air pressure inside, since the cuff will not deploy correctly and will be damaged. After servicing the suspension, be sure to fill it with air from an external source using a diagnostic tester before raising or lowering the vehicle on a lift platform or jack.

The air supply system consists of individual components. Each of them is described in detail below.

Compressor

The design and operating parameters of the compressor fully correspond to the device described for the Audi A6 self-leveling suspension. Below are only the differences for the 4-level air suspension of the Audi Allroad Quattro:

The inlet fitting is installed outside the vehicle in front of the spare tire and is not soundproofed;
The working pressure is increased to 16 atm. thanks to the presence of a pressure accumulator;
Reduced speed to reduce noise;
The suction fitting and discharge section are located in the area of the spare wheel and are equipped with a filter, which is also a noise damper for the passenger compartment;
An additional suction/discharge line valve ensures minimal noise, especially during air bleeding;
Temperature control is carried out using a sensor on the cylinder head, as well as real-time calculations by the control unit using a special temperature model.

Please note: during normal operation, the compressor only turns on when the engine is running.

Exceptions:

final diagnostic procedures;

basic system setup;

pre-start at excessively low system pressure.

Special fasteners consisting of spiral springs and rubber damping elements prevent the transmission of vibration to the body.

Air filter/noise absorber

Due to the location of the damping element (in the niche under the spare wheel), its maintenance is not required during operation.

Pressure accumulator

The receiver allows you to change the level of the car body quickly and with minimal noise in the operation of the air suspension, since the receiver can be refueled while the car is moving, when the noise of the compressor is not so noticeable.

Provided that there is sufficient air pressure in the receiver, changing the body level can be carried out without activating the compressor. “Sufficient pressure” means that before lifting the body in the suspension system there must be a pressure difference between the receiver and the air supports of at least 3 atm.

The receiver is made of aluminum and holds about 5 liters of air. The maximum operating pressure is 16 atm.

Air pumping procedure

When driving at a speed of less than 36 km/h, air is pumped primarily into the suspension air mounts (and only when operating pressure is reached into the receiver). The pressure accumulator is only filled when driving at speeds above 36 km/h. At travel speeds above 36 km/h, the working air supply is primarily provided by the compressor.

The described algorithm provides the best efficiency, including energy savings on compressor power, and the lowest noise level.

Pneumatic system diagram

Additional noise damper;
Check valve 1;
Air dryer;
Check valve 3;
Check valve 2;
Pressure relief valve;
Pneumatic release valve;
Compressor V66;
Electric release valve N111;
Receiver valve N311;
Valve for front left shock absorber strut N148;
Valve for front right shock absorber strut N149;
Valve for rear left shock absorber strut N150;
Valve for rear right shock absorber strut N151;
Receiver;
Front left air support;
Front right air support;
Rear left air support;
Rear right air support.

Solenoid valves

The 4-level air suspension has 6 solenoid valves. The discharge valve N111 forms a functional unit: the pneumatic valve together with the exhaust valve are integrated into a single dryer body. The outlet valve N111 is a 3/2-way valve that closes automatically without an electrical actuator. The pneumatic release valve acts as a pressure limiter and residual pressure holding device.

In four air springs, valves N148, N149, N150, N151 and accumulator valve N311 are combined in a single unit. They are designed as 2/2 way valves and close without a motor. Pressure on the air springs from the accumulator further helps to close them.

The pressure lines are color coded to avoid confusion when connecting them. The valve blocks are also color coded to match the colors of the connectors.

Temperature sensor G290 (overheat protection)

To improve the maintainability of the system, the temperature sensor G290 is attached to the compressor cylinder head. The J197 control unit operates according to a special temperature model to prevent overheating of the compressor while ensuring continuous operation.

To do this, the control unit calculates the maximum permissible temperature of the compressor depending on its operating time and the signals from the temperature sensor and turns off the compressor or blocks its activation when certain limit values are reached.

The pressure sensor G291 is integrated into the valve block and is used to monitor the pressure in the accumulator (receiver) and the suspension air mounts. Information from the receiver sensor is required for additional verification of the correctness of functions and for self-diagnosis. The individual pressure value in each of the air supports and the receiver can be set using the appropriate control of the solenoid valves.

Measurement of “personal” pressure is performed during discharge or filling of air supports. The recorded values are stored and updated in the memory of the control unit. The pressure in the battery is additionally monitored every 6 minutes while the vehicle is moving. Sensor G291 transmits a signal (voltage) proportional to the physical air pressure.

Level sensors are so-called “angle sensors”. Using a lever mechanism, changes in vehicle body height are converted into changes in the angle of the sensor's sensing element. The angle sensor used in the Audi Allroad Quattro is non-contact and operates on the inductive principle.

A feature of sensors of this type is the presence of two types of output signal, proportional to the angle of rotation of the sensing element. This allows the sensor to be used both to provide four levels of vehicle ride height and to control/adjust the angle of the headlights.

One output signal provides a voltage proportional to the angle of the sensing element (for headlight adjustment), and the second output signal provides information for the operation of the 4-level air suspension itself.

Please note: the body level sensors are identical in design, only the mounting brackets and mechanical connection to the body differ for the rear/front axle and right/left side.

Thus, the rotation of the sensor drive lever, as well as the output signal, will be opposite for the left and right sides of the body. For example, the amount of voltage during compression of the suspension increases on the sensors on one side and decreases on the other.

For technical reasons, the voltage for the left side level sensors (front left G78 and rear left G76) is supplied from the headlight control unit J431. The power supply to the right side level sensors (front right G289 and rear right G77) comes from the 4-level air suspension control unit J197. This arrangement ensures that if control unit J197 fails, the headlight control circuit will continue to operate.

Assignment of contacts for the level sensor

J431 – control unit J431 for the headlight angle control mechanism;
J197 – self-leveling unit.

Design and operation

An angle sensor essentially consists of a stator and a rotor. The stator is a multi-layer printed circuit board containing field coils, three receiver coils and control electronics. The three receiving coils have an angular shape and are located with a phase shift. The excitation coils are installed on the reverse side of the printed circuit board.

The rotor consists of a closed conductive circuit connected to an arm that swings with a mechanical drive arm. The conductor turns have the same geometric shape as the receiving coils.

Operation

The field coils are exposed to an alternating magnetic field, which induces EMF induction in the rotor turns. The current induced in the rotor produces its own alternating electromagnetic field around the rotor winding. Both alternating fields act on the receiving coils and induce two types AC in them.

While the flux of the rotor is independent of its angular position, the flux of the receiving coils is determined by their distance from the rotor, thereby determining its angular position.

When the rotor, depending on its angular position, “blocks the way” to the secondary current in the receiving coil, the voltage amplitudes change in strict accordance with the angle of the rotor position.

The electronic unit evaluates the AC compensation in the receiving coils, amplifies this signal and generates a proportional output voltage (dynamically changing). The output voltage is the receiving signal for the body level sensors and is used/processed by the suspension control unit.

Voltage amplitudes depending on the position of the rotor in relation to the take-up coil (an example of determining the position of the rotor).

Level sensors (brief description)

The advantages of “angle sensors” lie in their design - contactless signal reception reduces interference.

Producing a relative signal proportional to the rotation angle makes it sensitive to mechanical tolerances such as distance from the sensing element, sensor mounting/tilt error, etc. At the same time, electromagnetic interference is largely compensated by obtaining a relative signal.

Thus, the sensor design does not impose strict requirements on the magnetic characteristics of the material, operating temperature and the “age” of the components. Deviations in the measured signal can only be caused by “aging” or heating of the permanent magnets and the associated decrease in magnetic field strength.

Lights up for one second when terminal 15 is turned on (during self-diagnosis);
Lights up continuously when there are system errors or when the system is turned off;
Lights up continuously during system calibration when the basic settings have not been completed correctly;
Flashes when the body position is extremely low or high relative to specific driving parameters;
Flashes during control diagnostics.

The J197 unit is connected via the K-wire interface. The control board, integrated into the common unit, evaluates the signals from pressing the buttons for changing the body level on dashboard and transmits them in the form of a corresponding data protocol via the K-wire interface to the J197 control unit.

The control unit J197 transmits information about the vehicle height and current state systems back to the E281 also via the K-wire interface. After which the electronic unit turns on the corresponding indication LEDs.

To increase reliability, the “Raise” key performs the backup functions of an additional interface.

Please note that the K-wire connection between E281 and J197 does not support the K-wire self-test functionality between J197 and the diagnostic tester.

Interface

CAN information bus

The design of the four-level air suspension provides for data exchange between the self-leveling unit J197 and the control unit via a CAN bus (with the exception of several interfaces).

The diagram shows the algorithm for exchanging information between the gearbox control unit and the control control unit via the CAN bus.

Additional Algorithms

The control unit also has additional algorithms, let’s consider them too.

Signal from door switches

This is the “ground” from the central locking control unit, which signals the opening of the rear doors and/or trunk lid;
Also used as a “wake-up pulse” to bring the system from sleep mode to online mode.

Signal from terminal 50

signals the activation of the starter and serves to turn off the compressor during start-up.

If a low body position is detected after the wake-up pulse, the compressor is immediately switched on to enable the vehicle to move as quickly as possible. The compressor is turned off when the engine is started to conserve battery power and ensure proper starting power.

Car stop signal

Used as information to control the parking mode;
Receives as a ground signal from the block central lock J429;
Not taken into account in self-diagnosis. If there is no signal, parking level control is not performed.

Vehicle speed signal

It is a “square wave” generated by the instrument panel. Its frequency varies according to the speed of the vehicle;
Used to assess the state of the vehicle (movement/stop) and, accordingly, select a control algorithm.

Speed information is redundant, since this information is duplicated via the CAN bus.

To wire

The interface is used for system diagnostics (connection between control unit J197 and diagnostic tester connector). K-wire communicates with the system via regular information messages.

The K wire self-test interface should not be confused with the K-wire connection of the E281 operating unit to the J197 control unit.

Power supply for headlight leveling system

For the 4-level air suspension of the Audi Allroad Quattro, the position of the headlights is controlled using the control unit J197.

Please note: the central locking lock signal is not required for vehicles without parking level control.

Trailer connection signal

Comes from contact switch F216 of the trailer coupling mechanism. When the plug is inserted, contact switch F216 connects block J197 to ground.

Headlight angle control

When the height of the car body changes, that is, both axles rise/lower at once, this leads to a short-term decrease in the range of the headlights. To compensate for this effect, the Allroad Quattro is equipped with automatic dynamic headlight control (except for HID headlights).

Automatic Dynamic Headlight Height Control maintains the beam at a constant angle to the road regardless of vehicle height/level changes.

In order to prevent headlight correction errors from suspension vibrations on uneven surfaces, it is carried out only during some prolonged uniform movement of the vehicle (with low acceleration or without it at all).

If a change in vehicle level occurs, for example in motorway mode, the 4-level air suspension control unit J197 transmits a voltage pulse to unit J431. This immediately activates HRC to control the body modification algorithm:

to level up - first rear axle, then the front;
to lower the level - first the front axle, then the rear.

Control algorithms

Now, more about the air suspension control algorithms.

The central element of the air suspension system is the control unit, which, in addition to control functions, allows monitoring and diagnostics of the entire system. The control unit receives signals from the height sensors and uses them to determine the current position of the body.

If it differs from the “reference” ones for a given driving mode, the unit issues a correction command taking into account other controlled values, including response time and the actual amount of level deviation.

Depending on the driving conditions, the unit controls the suspension, implementing the appropriate algorithms. The comprehensive self-diagnosis feature makes air suspension inspection and maintenance easy. Depending on the importing country, Audi Allroad Quattro vehicles are equipped with two suspension control units.

Control units with numbers 4Z7 907 553A and 4Z7 907 553B implement different control algorithms. A single algorithm for both blocks (index “B”) is planned to be introduced in the future.

Please note: The system can be tested using built-in self-test routines. Or test device 1598/35.

Power supply for headlight leveling system

As described above in the "Level Sensors" section, the voltage for the left side sensors is supplied from the headlight control unit J431. The headlight adjustment mechanism does not require constant voltage, so power is supplied via control unit J431 (terminal 15) when the ignition is on.

However, all left and right side level sensors must be online even when the ignition is turned off. To allow the left level sensors to provide information, the 4-level suspension of the Audi Allroad Quattro has a connection between control unit J431 (HRC) and unit J197. This ensures that voltage is supplied to all level sensors when control unit J197 is active.

Modes

The Audi Allroad Quattro suspension system has different modes. The following is a description of each mode and how to control them.

Off-Road Mode/Normal Mode

Reaction time when level changes

Control algorithm for level changes

The level change is mainly carried out from axle to axle, as a result of which the difference in level between the left and right sides of the body is compensated, for example, if the load in the car is placed unevenly - closer to one side.

Level change process:

Increasing - first the rear axle, then the front;
Reduction - first the front axle, then the rear.

Starting and stopping

The “Start of motion” mode is designed to compensate for body deviations after parking, for example, when one of the passengers gets out or unloads the car, and before the trip due to a decrease in the air temperature in the air cylinders, natural air leakage, etc. The presence of these modes allows you to reduce the wait before starting to move to a minimum.

After turning off the ignition, the control unit goes into standby mode and remains active for a maximum of 15 minutes (power is supplied through terminal 30) until it goes into sleep mode.

To save battery energy when the engine is not running, polling of sensors and the set of functions of the unit are limited both in number and duration.

Sleep mode

To minimize power consumption, the control unit switches to “sleep mode” after 15 minutes. The duration of “sleep” cannot be adjusted. And the switching on of the block is activated by an impulse from the door limit switch.

When there is a signal from the door opening sensor, the unit “wakes up” and is ready to start working as soon as the ignition is turned on or a signal from the speed sensor appears (the car will move).

The system can switch between sleep mode and ready mode up to 15 times. For the next 15 wake-up procedures, the system will go into sleep mode after just 1 minute. The system can then only be activated using pin 15 and/or the speed sensor signal.

Lift mode

The air suspension control unit evaluates the signals from the level sensors for a stationary vehicle. If the body “spontaneously” rises, the unit initiates the “lift” mode. The “Lift” mode is designed to protect the pneumatic supports from excessive stretching in the absence of load when the car body is raised on the platform.

Please note: in order for the control unit to correctly recognize the “Lift” mode, the car should be raised as quickly as possible.

Using a trailer

The correct position of the hitch must be determined for the "Normal" body level. The connection of switch F216 to the 13-pin trailer connector is used to recognize its connection.

If the presence of a trailer is recognized, the manual suspension mode is switched on automatically and the “man” diode on the instrument panel lights up. The automatic suspension control is then terminated. The normal body level is set by control unit E281.

Please note: When towing a trailer, the suspension should always be in Normal mode.

It is necessary to ensure that the system switches to manual mode (for example, there is no automatic transition to manual mode if the trailer connection signal is not recognized).

In difficult road conditions, off-road modes (level 1 or 2) can be engaged, but the normal suspension mode must again be selected at speeds up to 35 km/h. Driving a vehicle with a trailer at a low level or in automatic mode not allowed!

Additional tools

Adapter cable 1598/35 from tester 1598/14 is used for troubleshooting and testing four-level air suspension sensors. Since the tester's pin layout is not compatible with that of the J197 control unit, template VAG 1598/35-1 must be used. The purpose of the contacts can only be found out using the VAG 1598/35-1 template.

The basic setting of the “reference” level air suspension system is carried out by entering the ground clearance value with the body position at the “Normal” level. The measured value from the center of the wheel to the lower edge of the wheel arch must be entered into the control unit using a diagnostic tester - function 10 “Adaptation”.

The codes are used to determine the reference value for the normal level ( Audi model Allroad Quattro - 402 mm). This means that the magnitude of specific body level sensor values will be taken into account adjusted to the “reference” value.

Due to the tolerances of the measuring system components, there will be a discrepancy between the actual (measured) and reference values. If data on the actual body level is available, the control unit J197 recognizes a discrepancy with the reference values, based on which the readings of the specific level sensors are corrected.

Advantages of the described measurement method:

no influence of fixed base setting due to...

…various tread depths and tire pressures.
...slight unevenness of the road surface.
...various tire sizes.

ease of setup.

Codes for AllroadQuattro

Self-diagnosis. Keyword: 34 Self-leveling suspension

Both generations of the diagnostic tester (VAG 1551/1552 and VAS 5051) are suitable for connection to the 4-level air suspension control unit. Due to the limited capabilities of the program cards, there are restrictions on text display for V.A.G. 1551 and 1552.

Control unit 4Z7 907 553A / B. Control algorithms for 4-level Audi Allroad Quattro air suspension, including range control.