Audi A4, S4

Since 2000 of release

Repair and car operation

Search of malfunctions - the general information and preliminary checks

Address also to Section Diagnostics of malfunctions and to below-mentioned Sections.

The system of ignition and the power supply system are the interconnected components of a control system of the engine. Therefore some components carry out some functions concerning functioning of different parts of a control system by the engine.

The general information

The system of ignition and fuel system have the general diagnostic system intended for preservation of codes of malfunctions and carrying out of diagnostics. At occurrence of malfunction the management block writes down some sequence of signals (a malfunction code) as which it is possible to consider subsequently as the special device (address to Section in which the description of procedure of check of fuel system is resulted) in memory.

If failures in work of the engine of the car are observed, the reason of it, most likely, can be found out, having investigated memory of the block of management. After reading of codes of malfunctions it is possible to find out, what knot is faulty, and to execute corresponding checks (either the knot, or its electroconducting).

It is not enough visual check of electroconducting and sockets — necessarily consider the information stored in memory of the block of management.

Preliminary checks

If malfunction has arisen soon after service of any knot, first of all carefully check up this knot and surrounding space. Probably, the reason is covered in carelessly established component or unreliably attached socket.

If you try to find out the reason of certain malfunction of the engine, for example capacity falling, in addition to the actions resulted more low measure a compression in cylinders. Be convinced that the fuel filter and an air cleaner varied according to the ordered intervals.

Keep in mind that after reading of codes of malfunctions they are necessary for removing from memory of the block of management by means of the same diagnostic scanner then to eliminate malfunction.

Open a cowl and be convinced of reliability of joining of tips of wires to plugs of the accumulator and absence on them corrosion. At detection of traces of corrosion or damages replace or clear wires. Similarly check up all tyres of grounding, having convinced by that they provide reliable contact (interfaced surfaces should be absolutely pure and without corrosion traces) with a body or the engine.

After that attentively examine all visible conducting laid in an impellent compartment. Be convinced of reliability of all connections. At the given stage you obviously damaged wires interest. They can be cut or ground about sharp or moving knots of the engine, for example, details of a suspension bracket or приводной a belt. Wire breakage can result from negligent installation of any knot. The wire can fuse at contact to release system. Most a plausible reason of damage of conducting is the wrong lining of its plaits in an impellent compartment after performance of repair or service of any knot.

Wires can be damaged or short-circuited without damage of their isolation. In this case survey in what will not result. Similar damages can arise after вытягивания wires or wrong placing of conducting in an impellent compartment. If you consider that similar damage is possible, check up a wire, following the sequence stated more low.

The damaged wire can be repaired, having soldered in in rupture a piece of a new wire. The soldering is necessary for reception of reliable contact. Isolation can be restored enough of an insulating tape or a thermoshrinkable tube. If damages are considerable and the damaged wire plays an essential role, the most true exit (though also expensive enough) will be replacement of a corresponding plait new.

After restoration of the damaged wire correctly arrange it in an impellent compartment, far from rotating and hot knots. Do not forget to fix a wire in intermediate clamps (if is).

Be convinced of reliability and cleanliness of all accessible sockets. All clamps should be established. If on an internal surface of a socket you cover up corrosion tracks (white or green adjournment, and also rust traces) or excessive pollution, remove it from the corresponding plug and carefully clear. For this purpose you can take advantage special of an aerosol. If the socket is seriously damaged, it is necessary to replace it. Keep in mind that in certain cases you should replace a plait entirely.

If you could remove completely traces of corrosion from a socket, fill with its preserving greasing then establish into place. You can learn type of greasing on HUNDRED.

On all models the position gauge коленвала (with its help it is defined also ВМТ the first cylinder) is established. Its working part can be polluted oil or a dust that can lead to failures in its work and, accordingly, to ignition admissions.

Attentively examine all vacuum hoses and the tubes located in an impellent compartment. Be convinced of reliability of a tightening of collars and absence of cracks, stratifications and traces of damages on hoses. Be convinced also that no hoses not передавлены and are bent too strongly, i.e. do not pass air. Special attention give to the hoses located near to keen edges, and also the ends of all hoses. It is necessary to replace all damaged hoses.

Be convinced of absence of traces of damages and pollution on hoses of system of ventilation картера. Be convinced also that they are not blocked from within. The quantity and installation sites of hoses of system depends on car model, but on all models the hose connecting the top part of the engine with a hose by an air inlet or the inlet pipeline is established. System hoses connect also the block of cylinders (or маслозаливную a mouth) to the inlet pipeline. These hoses deliver oil steams in combustion chambers. At pollution or blocking of these hoses the engine will work astably (especially on single turns).

Following from a fuel tank through the fuel filter to a fuel distributive highway along fuel pipelines, attentively examine them. At detection of traces of damages or excesses replace corresponding section. Special attention give to junctions of tubes. On them there can be the cracks leading to leaks of fuel.

Uncover cases of an air cleaner and examine an element. It should be rather pure and dry. Strongly polluted cleaner shows strong resistance to air stream that leads to appreciable decrease in capacity of the engine. Replace an air cleaner if necessary.

Start the engine and leave it to work on single turns.

At performance of any works in an impellent compartment at the working engine be extremely cautious. Besides high probability of reception of burns from the heated details of the engine or release system, you risk to receive a serious trauma from rotating details (for example, the fan of a radiator or drive a belt). Before the work beginning, first of all take measures and observe the safety precautions, stated in the beginning of each Chapter. Watch the hands, do not suppose hit of long hair or clothes in an impellent compartment. Steer clear of system of release and other hot details.

Following from an air inlet to an air cleaner and further to a throttle, be convinced of absence of leaks from hoses of giving of air (including nearby vacuum hoses). They can be found out on characteristic whistle. If whistle is not distributed, put a small amount of soap water on suspicious section of a hose. If the hose is damaged, the engine kind of work will change, and on the processed surface of a hose there will be bubbles (or, depending on pressure in a hose, water can start to be soaked up inside). At leak detection reliably tighten a collar or replace the damaged hose.

Similarly check up all system of release (from a collector to back section). Be convinced of absence of leaks of gases. For simplification of work you can lift the car on the lift, establish on a platform or over a hole. For carrying out of the most simple check stop up a final aperture of system of release and listen to system work. If you have heard characteristic whistle, leak takes place. At leak detection tighten a corresponding collar, bolts or nuts, replace a lining or the burnt through section.

The further check consists in serial moving of each socket on the corresponding plug at the working engine. Unreliable contact will be defined on change of a kind of work of the engine. Restore reliability of contact, having replaced or having cleared a corresponding socket. Keep in mind, it is necessary what in certain cases to change the whole plaits.

If as a result of preliminary checks you have not found out the reason of astable work of the engine, the car should be driven away on station of service for carrying out of more careful diagnostics with use of the special equipment.